View Filing Data

Print Document View Excel Document

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2016	Jan. 31, 2017	Jun. 30, 2016
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Trading Symbol	KOP
Entity Registrant Name	Koppers Holdings Inc.
Entity Central Index Key	0001315257
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		20,664,898
Entity Public Float			$ 617.9

Consolidated Statement of Operations - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Net sales	$ 1,416.2	$ 1,626.9	$ 1,555.0
Cost of sales (excluding items below)	1,127.9	1,366.7	1,343.7
Depreciation and amortization	52.9	59.0	44.0
Gain on sale of business	(2.1)	(3.2)	0.0
Impairment and restructuring charges	20.1	42.2	17.9
Goodwill impairment	0.0	67.2	0.0
Selling, general and administrative expenses	131.0	124.6	116.2
Operating profit (loss)	86.4	(29.6)	33.2
Other income, net	2.9	0.2	0.0
Interest expense	50.8	50.7	39.1
Income (loss) before income taxes	38.5	(80.1)	(5.9)
Income tax provision (benefit)	11.4	(4.2)	34.1
Income (loss) from continuing operations	27.1	(75.9)	(40.0)
Income (loss) from discontinued operations, net of tax (expense) benefit of $(0.3), $0.1 and $(1.0)	0.6	(0.1)	0.6
Net income (loss)	27.7	(76.0)	(39.4)
Net loss attributable to noncontrolling interests	(1.6)	(4.0)	(7.0)
Net income (loss) attributable to Koppers	$ 29.3	$ (72.0)	$ (32.4)
Basic -
Continuing operations	$ 1.39	$ (3.50)	$ (1.61)
Discontinued operations	0.03	(0.01)	0.03
Earnings (loss) per basic common share	1.42	(3.51)	(1.58)
Diluted -
Continuing operations	1.36	(3.50)	(1.61)
Discontinued operations	0.03	(0.01)	0.03
Earnings (loss) per diluted common share	$ 1.39	$ (3.51)	$ (1.58)
Weighted average shares outstanding (in thousands):
Basic	20,636	20,541	20,463
Diluted	21,055	20,541	20,463
Dividends declared per common share	$ 0.00	$ 0.00	$ 1.00

Consolidated Statement of Operations (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Income (loss) from discontinued operations, tax benefit	$ (0.3)	$ 0.1	$ (1.0)

- Definition

Amount of tax expense (benefit) related to a discontinued operation. Includes, but is not limited to, tax expense (benefit) related to income (loss) from operations during the phase-out period, tax expense (benefit) related to gain (loss) on disposal, tax expense (benefit) related to gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and tax expense (benefit) related to adjustments of a prior period gain (loss) on disposal.

+ References + Details

Consolidated Statement of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 27.7	$ (76.0)	$ (39.4)
Changes in other comprehensive income (loss):
Currency translation adjustment	(4.3)	(20.6)	(26.0)
Foreign currency transactions of long-term subsidiary investments	0.0	0.0	(4.6)
Derivative financial instrument net gain (loss), net of tax (expense) benefit of $(8.0), $1.2 and $2.6	12.9	(2.2)	(3.8)
Unrecognized pension prior service benefit, net of tax benefit of $0.0, $0.4 and $0.1	0.0	(0.7)	(0.2)
Unrecognized pension net gain (loss), net of tax (expense) benefit of $(2.0), $(1.0) and $8.0	2.3	3.7	(15.9)
Total comprehensive income (loss)	38.6	(95.8)	(89.9)
Comprehensive loss attributable to noncontrolling interests	(1.9)	(4.3)	(7.4)
Comprehensive income (loss) attributable to Koppers	$ 40.5	$ (91.5)	$ (82.5)

Consolidated Statement of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Tax (expense), derivative financial instrument	$ (8.0)	$ 1.2	$ 2.6
Unrecognized pension prior service benefit, tax benefit	0.0	0.4	0.1
Unrecognized pension net gain (loss), tax (expense) benefit	$ (2.0)	$ (1.0)	$ 8.0

Consolidated Balance Sheet - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Assets
Cash and cash equivalents	$ 20.8	$ 21.8
Accounts receivable, net of allowance of $3.8 and $6.5	136.8	155.0
Income tax receivable	3.8	4.6
Inventories, net	228.7	226.4
Loan to related party	8.9	9.5
Other current assets	39.1	27.0
Total current assets	438.1	444.3
Property, plant and equipment, net	280.8	277.8
Goodwill	186.4	186.6
Intangible assets, net	141.9	156.1
Deferred tax assets	27.1	36.6
Other assets	13.2	11.5
Total assets	1,087.5	1,112.9
Liabilities
Accounts payable	144.2	140.8
Accrued liabilities	106.3	99.8
Current maturities of long-term debt	42.6	39.9
Total current liabilities	293.1	280.5
Long-term debt	619.8	682.4
Accrued postretirement benefits	51.6	53.6
Deferred tax liabilities	6.3	5.7
Other long-term liabilities	82.1	103.1
Total liabilities	1,052.9	1,125.3
Commitments and contingent liabilities (Note 20)
Equity
Senior Convertible Preferred Stock, $0.01 par value per share; 10,000,000 shares authorized; no shares issued	0.0	0.0
Common Stock, $0.01 par value per share; 80,000,000 shares authorized; 22,140,680 and 22,015,994 shares issued	0.2	0.2
Additional paid-in capital	176.5	167.8
Accumulated deficit	(24.7)	(54.0)
Accumulated other comprehensive loss	(68.6)	(79.8)
Treasury stock, at cost, 1,475,792 and 1,459,164 shares	(53.0)	(52.7)
Total Koppers shareholders’ equity (deficit)	30.4	(18.5)
Noncontrolling interests	4.2	6.1
Total equity (deficit)	34.6	(12.4)
Total liabilities and equity (deficit)	$ 1,087.5	$ 1,112.9

Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Accounts receivable, allowance	$ 3.8	$ 6.5
Senior Convertible Preferred Stock, par value	$ 0.01	$ 0.01
Senior Convertible Preferred Stock, shares authorized	10,000,000	10,000,000
Senior Convertible Preferred Stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common Stock, shares authorized	80,000,000	80,000,000
Common Stock, shares issued	22,140,680	22,015,994
Treasury stock, shares	1,475,792	1,459,164

Consolidated Statement of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash provided by (used in) operating activities:
Net income (loss)	$ 27.7	$ (76.0)	$ (39.4)
Adjustments to reconcile net cash provided by operating activities:
Depreciation and amortization	52.9	59.0	44.0
Impairment of long-lived assets	3.5	14.7	4.7
Goodwill impairment	0.0	67.2	0.0
Gain on sale of business	(2.1)	(3.2)	0.0
Deferred income taxes	(0.1)	(16.0)	2.5
Equity loss, net of dividends received	1.0	3.1	1.6
Change in other liabilities	(5.0)	(5.5)	(10.3)
Non-cash interest expense	5.7	3.6	4.2
Stock-based compensation	8.9	3.8	4.7
Deferred revenue	(2.9)	27.6	(0.7)
Other	8.2	5.2	1.0
Changes in working capital:
Accounts receivable	12.7	34.1	13.4
Inventories	(3.3)	(4.3)	(14.0)
Accounts payable	5.0	25.0	(10.6)
Accrued liabilities	8.4	(19.6)	29.9
Other working capital	(1.1)	9.0	4.5
Net cash provided by operating activities	119.5	127.7	35.5
Cash (used in) provided by investing activities:
Capital expenditures	(49.9)	(40.7)	(83.8)
Acquisitions, net of cash acquired	0.0	(15.3)	(496.5)
Net cash (used in) provided by divestitures and asset sales	(3.8)	14.9	0.3
Net cash used in investing activities	(53.7)	(41.1)	(580.0)
Cash provided by (used in) financing activities:
Borrowings of revolving credit	595.7	612.1	572.5
Repayments of revolving credit	(625.4)	(685.9)	(368.0)
Borrowings of long-term debt	0.0	1.1	343.0
Repayments of long-term debt	(31.7)	(40.7)	0.0
Issuances of Common Stock	0.4	0.0	0.7
Proceeds from issuance of noncontrolling interest	0.0	0.0	1.4
Repurchases of Common Stock	(0.3)	(0.3)	(2.0)
Payment of deferred financing costs	(1.4)	(1.0)	(11.1)
Dividends paid	0.0	(8.7)	(20.4)
Net cash (used in) provided by financing activities	(62.7)	(123.4)	516.1
Effect of exchange rate changes on cash	(4.1)	7.5	(2.7)
Net increase (decrease) in cash and cash equivalents	(1.0)	(29.3)	(31.1)
Cash and cash equivalents at beginning of period	21.8	51.1	82.2
Cash and cash equivalents at end of period	20.8	21.8	51.1
Cash paid during the year for:
Interest	42.7	43.9	32.9
Income taxes, net	$ 11.6	$ 26.3	$ 16.1

Consolidated Statement of Shareholders' Equity - USD ($) $ in Millions	Total	Senior Convertible Preferred Stock [Member]	Common Stock [Member]	Noncontrolling Interests [Member]	(Accumulated Deficit) Retained Earnings [Member]	Currency Translation Adjustment [Member]	Unrecognized (Losses) Gains on Cash Flow Hedges [Member]	Unrecognized Pension Prior Service Cost [Member]	Unrecognized Pension Net Loss [Member]	Additional Paid-in Capital [Member]	Treasury Stock	Accumulated Other Comprehensive Loss [Member]	Koppers Shareholder's Equity (Deficit) [Member]
Balance at Dec. 31, 2013		$ 0.0	$ 0.2	$ 20.0	$ 71.3	$ 24.0	$ 0.0	$ 0.8	$ (35.0)	$ 158.9	$ (50.4)
Net loss attributable to noncontrolling interests	$ (7.0)			(7.0)
Net income (loss) attributable to Koppers	(32.4)				(32.4)
Common Stock dividends					(20.9)
Purchases											(2.0)
Change in currency translation adjustment excluding foreign currency transactions of long-term subsidiary investments	(26.0)			(0.4)		(25.7)
Foreign currency transactions of long-term subsidiary investments	(4.6)					(4.6)
Reclassification of unrealized losses on cash flow hedges to expense, net of tax expense of $3.7, $3.5 and $0.2							0.3
Change in cash flow hedges, net of tax (expense) benefit of $(4.3), $4.7 and $2.8							(4.1)
Reclassification of unrecognized prior service benefit to income,net of tax benefit of $0.0, $0.4 and $0.1								(0.1)
Reclassification of unrecognized pension net loss to expense, net of tax benefit of $2.3, $2.2 and $1.4									2.4
Revaluation of unrecognized pension net loss, net of tax benefit of $(0.3), $(1.2) and $(9.4)									(18.3)
Investment in noncontrolling interests				1.3
Dividends to noncontrolling interests				0.0
Employee stock plans										5.6
Balance at Dec. 31, 2014	83.9	0.0	0.2	13.9	18.0	(6.3)	(3.8)	0.7	(50.9)	164.5	(52.4)	$ (60.3)	$ 70.0
Net loss attributable to noncontrolling interests	(4.0)			(4.0)
Net income (loss) attributable to Koppers	(72.0)				(72.0)
Common Stock dividends					0.0
Purchases											(0.3)
Change in currency translation adjustment excluding foreign currency transactions of long-term subsidiary investments	(20.6)			(0.3)		(20.3)
Foreign currency transactions of long-term subsidiary investments	0.0					0.0
Reclassification of unrealized losses on cash flow hedges to expense, net of tax expense of $3.7, $3.5 and $0.2							5.4
Change in cash flow hedges, net of tax (expense) benefit of $(4.3), $4.7 and $2.8							(7.6)
Reclassification of unrecognized prior service benefit to income,net of tax benefit of $0.0, $0.4 and $0.1								(0.7)
Reclassification of unrecognized pension net loss to expense, net of tax benefit of $2.3, $2.2 and $1.4									4.0
Revaluation of unrecognized pension net loss, net of tax benefit of $(0.3), $(1.2) and $(9.4)									(0.3)
Investment in noncontrolling interests				0.0
Dividends to noncontrolling interests				(3.5)
Employee stock plans										3.3
Balance at Dec. 31, 2015	(12.4)	$ 0.0	$ 0.2	6.1	(54.0)	(26.6)	(6.0)	0.0	(47.2)	167.8	(52.7)	(79.8)	(18.5)
Net loss attributable to noncontrolling interests	(1.6)			(1.6)
Net income (loss) attributable to Koppers	29.3				29.3
Common Stock dividends					0.0
Purchases											(0.3)
Change in currency translation adjustment excluding foreign currency transactions of long-term subsidiary investments	(4.3)			(0.3)		(4.0)
Foreign currency transactions of long-term subsidiary investments	0.0					0.0
Reclassification of unrealized losses on cash flow hedges to expense, net of tax expense of $3.7, $3.5 and $0.2							5.6
Change in cash flow hedges, net of tax (expense) benefit of $(4.3), $4.7 and $2.8							7.3
Reclassification of unrecognized prior service benefit to income,net of tax benefit of $0.0, $0.4 and $0.1								0.0
Reclassification of unrecognized pension net loss to expense, net of tax benefit of $2.3, $2.2 and $1.4									3.9
Revaluation of unrecognized pension net loss, net of tax benefit of $(0.3), $(1.2) and $(9.4)									(1.6)
Investment in noncontrolling interests				0.0
Dividends to noncontrolling interests				0.0
Employee stock plans										8.7
Balance at Dec. 31, 2016	$ 34.6			$ 4.2	$ (24.7)	$ (30.6)	$ 6.9	$ 0.0	$ (44.9)	$ 176.5	$ (53.0)	$ (68.6)	$ 30.4

Consolidated Statement of Shareholders' Equity (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Unrecognized (Losses) Gains on Cash Flow Hedges [Member]
Unrealized losses on cash flow hedges to expense, tax expense	$ 3.7	$ 3.5	$ 0.2
Deferred losses on cash flow hedges, tax (expense) benefit	(4.3)	4.7	2.8
Unrecognized Pension Prior Service Cost [Member]
Reclassification of unrecognized pension prior service benefit, tax benefit	0.0	0.4	0.1
Unrecognized Pension Net Loss [Member]
Reclassification of unrecognized pension net loss, tax expense	2.3	2.2	1.4
Revaluation of unrecognized pension net loss, tax benefit	$ (0.3)	$ (1.2)	$ (9.4)

Description of Business	12 Months Ended
Description of Business	Dec. 31, 2016
Accounting Policies [Abstract]
Description of Business	1. Description of Business Parent company of Koppers Inc. – In these financial statements, unless otherwise indicated or the context requires otherwise, when the terms “Koppers,” the “Company,” “we,” “our” or “us,” are used, they mean Koppers Holdings Inc. (“Koppers Holdings”) and its subsidiaries on a consolidated basis. The use of these terms is not intended to imply that Koppers Holdings and Koppers Inc. are not separate and distinct legal entities from each other and from their respective subsidiaries. Koppers Holdings has no direct operations and no significant assets other than the stock of Koppers Inc. It depends on the dividends from the earnings of Koppers Inc. and its subsidiaries to generate the funds necessary to meet its financial obligations. The terms of Koppers Inc.’s revolving credit facility prohibit Koppers Inc. from paying dividends and otherwise transferring assets except for certain limited dividends. Further, the terms of the indenture governing Koppers Inc.’s Senior Notes due 2025 significantly restrict Koppers Inc. from paying dividends and otherwise transferring assets to Koppers Holdings. Business description – The Company is a global integrated provider of treated wood products, wood treatment chemicals and carbon compounds for use in a variety of markets including the railroad, specialty chemical, utility, residential lumber, agriculture, aluminum, steel, rubber and construction industries. The Company’s business is operated through three business segments, Railroad and Utility Products and Services (“RUPS”), Performance Chemicals (“PC”) and Carbon Materials and Chemicals (“CMC”). The Company’s Railroad and Utility Products and Services segment sells treated and untreated wood products, rail joint bars and services primarily to the railroad industry and treated wood products to the utility industry. Railroad products include procuring and treating items such as crossties, switch ties and various types of lumber used for railroad bridges and crossings and the manufacture of rail joint bars. Utility products include transmission and distribution poles and pilings. The Company’s Performance Chemicals segment develops, manufactures, and markets wood preservation chemicals and wood treatment technologies and services a diverse range of end-markets including infrastructure, residential and commercial construction and agriculture. The Company’s Carbon Materials and Chemicals segment is primarily a manufacturer of creosote, carbon pitch, naphthalene, phthalic anhydride and carbon black feedstock. Creosote is used in the treatment of wood and carbon black feedstock is used in the production of carbon black. Carbon pitch is a critical raw material used in the production of aluminum and for the production of steel in electric arc furnaces. Naphthalene is used for the production of phthalic anhydride and as a surfactant in the production of concrete. Phthalic anhydride is used in the production of plasticizers, polyester resins and alkyd paints.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2016

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Basis of presentation – The consolidated financial statements include the accounts of the Company and all majority-owned subsidiaries for which the Company is deemed to exercise control over its operations. All significant intercompany transactions have been eliminated in consolidation. The Company’s investments in 20 percent to 30 percent-owned companies in which it has the ability to exercise significant influence over operating and financial policies are accounted for using the equity method of accounting. Accordingly, the Company’s share of the earnings of these companies is included in the accompanying consolidated statement of operations. Certain prior period amounts in the notes to the consolidated financial statements have been reclassified to conform to the current period’s presentation.

Use of estimates – Accounting principles generally accepted in the U.S. require management to make estimates and judgments that affect the reported amounts of assets and liabilities and the disclosure of contingencies on the date of the financial statements as well as the reported amounts of revenues and expenses during the reporting period. Estimates have been prepared on the basis of the most current and best available information and actual results could differ materially from these estimates.

Foreign currency translation – For consolidated entities outside of the U.S. that prepare financial statements in currencies other than the U.S. dollar, results of operations and cash flows are translated at average exchange rates during the period, and assets and liabilities are translated at end-of-period exchange rates. Cumulative translation adjustments are included as a separate component of accumulated other comprehensive loss in shareholders’ equity.

Foreign currency transaction gains and losses result from transactions denominated in a currency which is different than the currency used by the entity to prepare its financial statements. Foreign currency transaction (losses) gains were $(1.3) million, $(10.4) million and $0.6 million for the years ended December 31, 2016, 2015 and 2014, respectively.

Revenue recognition – The Company recognizes revenue when the risks and rewards of ownership and title to the product have transferred to the customer. Revenue recognition generally occurs at the point of shipment; however in certain circumstances as shipping terms dictate, revenue is recognized at the point of destination. Shipping and handling costs are included as a component of cost of sales.

The Company recognizes revenue related to the procurement of certain untreated railroad crossties upon transfer of title to the customer, which occurs upon delivery to the Company’s plant and acceptance by the customer. Service revenue, consisting primarily of wood treating services, is recognized at the time the service is provided. Payment on sales of untreated railroad crossties and wood treating services are generally due within 30 days of the invoice date. The Company’s recognition of revenue with respect to untreated crossties meets all the recognition criteria of Securities and Exchange Commission Staff Accounting Bulletin Topic 13.A.3., including transfer of title and risk of ownership, the existence of fixed purchase commitments and delivery schedules established by the customer, and the completion of all performance obligations by the Company. Revenue recognized for untreated crosstie sales for the years ended December 31, 2016, 2015 and 2014 amounted to $129.2 million, $129.8 million and $93.4 million, respectively.

Research and development – Research and development costs are expensed as incurred and are included in selling, general and administrative expenses. These costs totaled $6.6 million in 2016, $5.2 million in 2015 and $3.4 million in 2014.

Cash and cash equivalents – Cash and cash equivalents include cash on hand and on deposit and investments in highly liquid investments with an original maturity of 90 days or less.

Accounts receivable – The Company maintains allowances for doubtful accounts for estimated losses resulting from the inability of its customers to make required payments. In circumstances where the Company becomes aware of a specific customer’s inability to meet its financial obligations to Koppers, a specific reserve for bad debts is recorded against amounts due. If the financial condition of the Company’s customers were to deteriorate, resulting in an inability to make payments, additional allowances may be required.

Inventories – In the United States, CMC and RUPS inventories are valued at the lower of cost, utilizing the last-in, first-out (“LIFO”) basis, or market. PC inventories and all other inventories outside of the United States are valued at the lower of cost, utilizing the first-in, first-out (“FIFO”) basis, or market. Market represents replacement cost for raw materials and net realizable value for work in process and finished goods. LIFO inventories constituted approximately 65 percent and 66 percent of the FIFO inventory value at December 31, 2016 and 2015, respectively. In 2016, 2015 and 2014, we recorded inventory write-downs of $0.6 million, $1.4 million and $2.4 million, respectively, related to lower of cost or market conditions for our subsidiaries that value inventory on the FIFO basis.

Property, plant and equipment – Property, plant and equipment are recorded at purchased cost and include improvements which significantly increase capacities or extend useful lives of existing plant and equipment. Depreciation expense is calculated by applying the straight-line method over estimated useful lives. Estimated useful lives for buildings generally range from 10 to 20 years and depreciable lives for machinery and equipment generally range from 3 to 15 years. Net gains and losses related to asset disposals are recognized in earnings in the period in which the disposal occurs. Routine repairs, replacements and maintenance are expensed as incurred.

The Company periodically evaluates whether current facts and circumstances indicate that the carrying value of its depreciable long-lived assets may not be recoverable. If an asset, or logical grouping of assets, is determined to be impaired, the asset is written down to its fair value using discounted future cash flows and, if available, quoted market prices. Refer to Note 4 “Plant Closures and Discontinued Operations” for additional information.

Goodwill and other intangible assets – Goodwill and other purchased intangible assets are included in the identifiable assets of the business segment to which they have been assigned. The Company performs impairment tests annually for goodwill, and more often as circumstances require. When it is determined that impairment has occurred, an appropriate charge to earnings is recorded. The Company performed its annual impairment test in the fourth quarters of 2016 and 2015. Refer to Note 14, "Goodwill and Other Identifiable Intangible Assets," for a discussion of goodwill impairment recorded during the year ended December 31, 2015.

Identifiable intangible assets, other than goodwill, are recorded at cost. Identifiable intangible assets that do not have indefinite lives are amortized on a straight-line basis over their estimated useful lives.

Deferred income taxes – Deferred tax assets and liabilities are recognized for future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. The effect on deferred tax assets and liabilities of a change in tax laws is recognized in earnings in the period the new laws are enacted. A valuation allowance is recorded to reduce the carrying amounts of deferred tax assets unless it is more likely than not that such assets will be realized. Deferred tax liabilities have not been recognized for the undistributed earnings of certain foreign subsidiaries because management intends to permanently reinvest such earnings in foreign operations.

Self-insured liabilities – The Company is self-insured for property, casualty and workers’ compensation exposures up to various stop-loss coverage amounts. Losses are accrued based upon the Company’s estimates of the liability for the related deductibles of claims incurred. Such estimates utilize actuarial methods based on various assumptions, which include but are not limited to, the Company’s historical loss experience and projected loss development factors. In 2016 and 2015, reversals of self-insured liabilities occurred as a result of favorable loss trends related to self-insured claims.

	2016			2015
(Dollars in millions)
Self-insured liabilities at beginning of year	$	8.0		$	8.2
Expense		5.1			2.6
Reserves recoverable from insurance		2.4			0.0
Reversal of self-insured liabilities		(1.7	)		(1.0	)
Cash expenditures		(2.9	)		(1.8	)
Self-insured liabilities at end of year	$	10.9		$	8.0

Derivative financial instruments – The Company uses swap contracts to manage copper price risk associated with forecasted purchases of materials used in the Company’s manufacturing processes. The Company uses forward exchange contracts to hedge exposure to currency exchange rate changes on transactions and other commitments denominated in a foreign currency. Contracts are not held for trading or speculative purposes. The Company recognizes the fair value of the swap contracts and forward contracts as an asset or liability at each reporting date. The Company designates certain of the swap contracts as cash flow hedges and the effective portion of the gain or loss on the derivative is reported as a component of other comprehensive (loss) earnings until it is reclassified into earnings when the hedged transaction affects earnings. Gains and losses from hedge ineffectiveness are recognized in current earnings. For swap contracts that are not designated as cash flow hedges, changes in the fair value of those forward contracts are recognized immediately in earnings. Because the Company has not elected to designate the forward exchange contracts for hedge accounting treatment, changes in the fair value of the forward exchange contracts are recognized immediately in earnings.

Asset retirement obligations – Asset retirement obligations are initially recorded at fair value and are capitalized as part of the cost of the related long-lived asset when sufficient information is available to estimate fair value. The capitalized costs are subsequently charged to depreciation expense over the estimated useful life of the related long-lived asset. The fair value of the obligation is determined by calculating the discounted value of expected future cash flows and accretion expense is recorded each month to ultimately increase this obligation to full value.

The Company recognizes asset retirement obligations for the removal and disposal of residues; dismantling of certain tanks required by governmental authorities; cleaning and dismantling costs for owned rail cars; cleaning costs for leased rail cars and barges; and site demolition, when required by governmental authorities or by contract.

The following table describes changes to the Company’s asset retirement obligation liabilities at December 31, 2016 and 2015:

	2016			2015
(Dollars in millions)
Asset retirement obligation at beginning of year	$	46.5		$	30.5
(Divestiture) acquisition		(8.0	)		0.7
Accretion expense		7.1			3.7
Revision in estimated cash flows ^(a)		2.7			24.4
Cash expenditures		(11.4	)		(12.1	)
Currency translation		(0.9	)		(0.7	)
Balance at end of period	$	36.0		$	46.5

(a) Revision in estimated cash flows for 2016 and 2015 includes $2.7 and $23.4 million of charges related to restructuring activities, respectively. See Note 4. “Plant Closures and Discontinued Operations” for additional information.

Litigation and contingencies – Amounts associated with litigation and contingencies are accrued when management, after taking into consideration the facts and circumstances of each matter including any settlement offers, has determined that it is probable that a liability has been incurred and the amount of loss can be reasonably estimated. Legal costs for litigation are expensed as incurred with the exception of legal fees relating to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) sites.

Other current assets – Included in other current assets are prepaid expenses totaling $17.0 million and $17.0 million at December 31, 2016 and 2015, respectively.

Environmental liabilities – The Company accrues for remediation costs and penalties when the responsibility to remediate is probable and the amount of related cost is reasonably estimable. If only a range of potential liability can be estimated and no amount within the range is more probable than another, the accrual is recorded at the low end of that range. Remediation liabilities are discounted if the amount and timing of the cash disbursements are readily determinable.

Deferred revenue – The Company defers revenues associated with extended product warranty liabilities based on historical loss experience and sales of extended warranties on certain products. In addition, the Company received an advance payment of $30.0 million in 2015 related to an amendment to a 50-year supply agreement with a customer in China. The deferred revenue associated with this amendment will be amortized over the life of the underlying contract. The following table describes changes to the Company’s deferred revenue at December 31, 2016 and 2015:

	2016			2015
(Dollars in millions)
Deferred revenue at beginning of year	$	30.1		$	2.5
Advance payment		0.0			30.0
Revenue earned		(0.8	)		(1.0	)
Currency translation		(2.1	)		(1.4	)
Deferred revenue at end of year	$	27.2		$	30.1

Stock-based compensation – The Company records compensation expense for non-vested stock options over the vesting period based on the fair value at the date of grant. No compensation cost is recognized for any stock awards that are forfeited in the event the recipient fails to meet the vesting requirements.

New Accounting Pronouncements	12 Months Ended
New Accounting Pronouncements	Dec. 31, 2016
Accounting Changes And Error Corrections [Abstract]
New Accounting Pronouncements	3. New Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 requires an entity to recognize revenue in a manner that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In March 2016, the FASB issued ASU No. 2016-08, “Principal versus Agent Considerations (Reporting Revenue Gross versus Net),” that amends the principal versus agent guidance in ASU 2014-09. ASU 2016-08 clarifies that the analysis must focus on whether the entity has control of the goods or services before they are transferred to the customer. In April 2016, the FASB issued ASU 2016-10, “Identifying Performance Obligations and Licensing”, which clarifies the implementation guidance in ASU 2014-09 relating to the identification of performance obligations in a contract, including how entities should account for shipping and handling services it provides after control of goods transfers to a customer. In May 2016, the FASB issued ASU 2016-12, “Narrow-Scope Improvements and Practical Expedients”, which clarifies revenue recognition guidance related to the presentation of sales taxes, noncash consideration, and completed contracts and contract modifications. In December 2016, the FASB issued ASU 2016-20, “Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers”, which clarifies the scope and application of the adoption of the new revenue recognition standard. Collectively, the revenue recognition ASC updates are effective for annual reporting periods beginning after December 15, 2017 with early adoption permitted and allows for the use of either the retrospective or cumulative effect transition method. The Company intends to adopt these standards effective January 1, 2018 but has not yet determined which transition method will be used. The Company has a project team analyzing significant contracts with customers to determine the impact of the adoption of the ASU updates on the Company’s financial statements and disclosures. The Company will continue to assess the impact the ASC updates will have on its revenue arrangements with a final evaluation of the impact of adopting these ASC updates expected to be completed during the third quarter of 2017. In August 2016, the FASB issued ASU No. 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments.” The update clarifies how entities should classify certain cash receipts and cash payments on the statement of cash flow. The amendments in this update are effective for periods beginning after December 15, 2017. The Company is in the process of assessing the impact the adoption of this ASU will have on its consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-09, “Improvements to Employee Share-Based Payment Accounting.” This ASU makes several modifications related to the accounting for forfeitures, employer tax withholding on share-based compensation and the financial statement presentation of excess tax benefits or deficiencies. The amendments in this ASU are effective for periods beginning after December 15, 2016. The Company does not expect the adoption of this ASU will have a material impact on its consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842).” ASU 2016-02 requires an entity to recognize a right-of-use asset and lease liability for all leases with terms of more than one year. Recognition, measurement and presentation of expenses will depend on classification as a finance or operating lease. The standard is effective January 1, 2019 and early adoption is permitted. The guidance requires a modified retrospective adoption. The Company is currently evaluating the impact the adoption of ASU 2016-02 will have on its consolidated financial statements. In April 2015, the FASB issued ASU No. 2015-03, “Simplifying the Presentation of Debt Issuance Costs,” which requires companies to present debt issuance costs associated with a debt liability as a deduction from the carrying amount of that debt liability on the balance sheet rather than being capitalized as an asset. The standard is effective for interim and annual periods beginning after December 15, 2015, and retrospective presentation is required. The Company adopted this guidance as of January 1, 2016 and the consolidated financial statements have been revised to reflect the retrospective presentation requirement. As a result, $12.5 million and $14.6 million of debt issuance costs have been reclassified from other assets to long-term debt as of December 31, 2015 and December 31, 2014, retrospectively. This reclassification has also been reflected within the notes to the consolidated financial statements as applicable. In August 2014, the FASB issued ASU No. 2014-15, “Disclosure of Uncertainties About an Entity’s Ability to Continue as a Going Concern”, which requires management to perform interim and annual assessments of an entity’s ability to continue as a going concern within one year of the date the financial statements are issued and provides guidance on determining when and how to disclose going concern uncertainties in the financial statements. The Company adopted this ASU for the year ended December 31, 2016 and the adoption did not have a material effect on the Company’s consolidated financial statements.

- Definition

The entire disclosure of changes in accounting principles, including adoption of new accounting pronouncements, that describes the new methods, amount and effects on financial statement line items.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Change in Accounting Principle
-URI http://asc.fasb.org/extlink&oid=6507316

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Direct Effects of a Change in Accounting Principle
-URI http://asc.fasb.org/extlink&oid=66092750

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22583-107794

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Indirect Effects of a Change in Accounting Principle
-URI http://asc.fasb.org/extlink&oid=6515603

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22580-107794

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.10-01.(b)(6))
-URI http://asc.fasb.org/extlink&oid=27015980&loc=d3e46468-122699

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Accounting Change
-URI http://asc.fasb.org/extlink&oid=6503790

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22499-107794

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Retrospective Application
-URI http://asc.fasb.org/extlink&oid=6523989

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=68064558&loc=d3e765-108305

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=68064558&loc=d3e725-108305

+ Details

Plant Closures and Discontinued Operations

12 Months Ended

Dec. 31, 2016

Discontinued Operations And Disposal Groups [Abstract]

Plant Closures and Discontinued Operations

4. Plant Closures and Discontinued Operations

On October 24, 2016, the Company agreed to a long-term lease of its wood treatment facility in Houston, Texas to a third party. This facility, owned by the Company’s wholly-owned subsidiary, Wood Protection L.P., is engaged in the manufacturing and sale of pressure-treated dimensional lumber and had revenue of approximately $8 million for the year ended December 31, 2016 and $14 million for the year ended December 31, 2015.

In March 2016, the Company discontinued production at its 60-percent owned CMC plant located in Tangshan, China. The Company’s 60-percent owned subsidiary, Koppers (China) Carbon & Chemical Company Limited (“KCCC”) is located adjacent to a metallurgical coke facility owned by KCCC’s minority partner, which also closed. The KCCC plant relied on the coke facility for a significant portion of raw material supply, utilities and other shared services. In 2015, the Company recorded a severance charge of $0.9 million. For the year ended December 31, 2016, the Company has recorded inventory write-down charges of $0.7 million in connection with the facility.

In February 2016, the Company announced plans, which were approved by management and the board in December 2015, to cease coal tar distillation operations at both of its United Kingdom CMC facilities. Accordingly, the Company recorded environmental charges, asset retirement obligations and fixed asset impairment charges totaling $13.9 million during the year ended December 31, 2015. For the year ended December 31, 2016, the Company recorded severance charges of $1.5 million. In July 2016, the Company sold substantially all of its tar distillation properties and assets in the United Kingdom. In exchange, the Company transferred cash to the buyer and the buyer assumed historical environmental and asset retirement obligations. The Company recognized a gain of $2.1 million on this transaction. This gain is reported in “Gain on sale of business” on the Condensed Consolidated Statement of Operations and Comprehensive Income (Loss).

In January 2016, the Company announced its decision, which was approved by management and the board in December 2015, to discontinue coal tar distillation activities at its CMC plant located in Clairton, Pennsylvania. Accordingly, the Company recorded severance, inventory write-down, asset retirement obligation and fixed asset impairment charges totaling $18.8 million during the year ended December 31, 2015. For the year ended December 31, 2016, the Company recorded additional plant closure costs and fixed asset impairment charges totaling $6.4 million in connection with the closure of the facility. Coal tar distillation activities at Clairton were substantially discontinued at the end of July 2016. As of December 31, 2016, all depreciable fixed assets directly related to the facility have been impaired.

In August 2015, the Company closed its RUPS plant located in Green Spring, West Virginia. Accordingly, the Company recorded severance, asset retirement obligation and fixed asset impairment charges of $5.7 million during the year ended December 31, 2015. For the year ended December 31, 2016, the Company has recorded additional plant closure costs of $3.0 million in connection with the closure of the facility.

In January 2015, Koppers Inc. sold its RUPS North American utility pole business for cash of $12.3 million and a promissory note of $1.6 million. The Company recognized a gain of $3.2 million on this transaction. The promissory note is repayable in three remaining equal annual installments. This gain is reported in “Gain on sale of business” on the Condensed Consolidated Statement of Operations and Comprehensive Income (Loss). The proceeds of the sale are reported within “Net cash proceeds from divestitures and asset sales” on the Condensed Consolidated Statement of Cash Flows. For the year ended December 31, 2016, the Company has recorded additional plant closure costs of $2.7 million in connection with assets that were associated with this business line.

In April 2014, the Company ceased its coal tar distillation activities at its CMC facility located in Uithoorn, the Netherlands. In the second quarter of 2016, the Company recorded a $3.7 million net present value accrual related to future real estate lease obligations, net of estimated sublease revenue, at the closed site. The Company determined that it met the cease-use criteria required for the accrual of these costs upon the completion of site demolition in April 2016.

Details of the restructuring activities and related reserves are as follows:

	Severance and employee benefits			Environmental remediation			Asset retirement			Other			Total
(Dollars in millions)
Reserve at December 31, 2014	$	0.0		$	4.1		$	3.9		$	0.1		$	8.1
Accrual		2.2			0.6			23.4			1.3			27.5
Costs charged against assets		0.0			0.0			0.0			(1.3	)		(1.3	)
Reversal of accrued charges		0.0			0.0			(0.3	)		0.0			(0.3	)
Cash paid		(0.2	)		0.0			(4.8	)		(0.1	)		(5.1	)
Currency translation		0.0			(0.4	)		(0.3	)		0.0			(0.7	)
Reserve at December 31, 2015	$	2.0		$	4.3		$	21.9		$	0.0		$	28.2
Accrual		2.4			0.1			5.6			5.6			13.7
Costs charged against assets		0.0			0.0			0.0			(1.9	)		(1.9	)
Reversal of accrued charges		(1.9	)		(0.5	)		(8.7	)		(0.1	)		(11.2	)
Cash paid		(1.0	)		(2.4	)		(8.1	)		(0.2	)		(11.7	)
Currency translation		(0.1	)		0.0			(0.7	)		(0.2	)		(1.0	)
Reserve at December 31, 2016	$	1.4		$	1.5		$	10.0		$	3.2		$	16.1

- Definition

The entire disclosure related to a disposal group. Includes, but is not limited to, a discontinued operation, disposal classified as held-for-sale or disposed of by means other than sale or disposal of an individually significant component.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=65878427&loc=SL51721533-107759

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 4B
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721665-107760

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5C
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721675-107760

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3A
-URI http://asc.fasb.org/extlink&oid=64862545&loc=SL51724579-110230

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 4A
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721663-107760

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64862545&loc=d3e2941-110230

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=64827811&loc=d3e1361-107760

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5B
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721673-107760

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 3A
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721659-107760

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5A
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721671-107760

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5D
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721677-107760

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64827811&loc=d3e1474-107760

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721683-107760

+ Details

Related Party Transactions	12 Months Ended
Related Party Transactions	Dec. 31, 2016
Related Party Transactions [Abstract]
Related Party Transactions	5. Related Party Transactions As of December 31, 2016, the Company has loaned $9.5 million to Tangshan Koppers Kailuan Carbon Chemical Company Limited (“TKK”), a 30-percent owned tar distillation facility in the Hebei Province of China. The amount reported in the consolidated balance sheet is net of accumulated equity losses in TKK of $1.1 million and interest receivable of $0.5 million. In 2015, TKK defaulted on the first installment payment on the loan and each installment payment thereafter. In November 2016, the Company sold its 30-percent equity interest in TKK to TKK’s controlling shareholder and agreed to a revised installment payment plan which is guaranteed by TKK’s controlling shareholder. The first two installment payments totaling $5.2 million, inclusive of accrued interest, under the revised payment plan were received in January and February 2017. The remaining installment payments are expected to be received by June 30, 2017.

Fair Value Measurements

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Fair Value Measurements

6. Fair Value Measurements

Carrying amounts and the related estimated fair values of the Company’s financial instruments as of December 31, 2016 and 2015 are as follows:

	December 31, 2016				December 31, 2015
	Fair Value		Carrying Value		Fair Value		Carrying Value
(Dollars in millions)
Financial assets:
Cash and cash equivalents, including restricted cash	$	20.8	$	20.8	$	21.8	$	21.8
Investments and other assets^(a)		1.1		1.1		1.1		1.1
Financial liabilities:
Long-term debt (including current portion)	$	669.6	$	662.4	$	724.6	$	722.3

(a)	Excludes equity method investments.

Cash and cash equivalents – The carrying amount approximates fair value because of the short maturity of those instruments.

Investments and other assets – Represents the broker-quoted cash surrender value on universal life insurance policies. This asset is classified as Level 2 in the valuation hierarchy and is measured from values received from financial institutions.

Debt – The fair value of the Company’s long-term debt is estimated based on the market prices for the same or similar issues or on the current rates offered to the Company for debt of the same remaining maturities (Level 2). The fair values of the revolving credit facility approximate carrying value due to the variable rate nature of these instruments.

Earnings per Common Share

12 Months Ended

Dec. 31, 2016

Earnings Per Share [Abstract]

Earnings per Common Share

7. Earnings per Common Share

The computation of basic earnings per common share for the periods presented is based upon the weighted average number of common shares outstanding during the periods. The computation of diluted earnings per common share includes the effect of non-vested nonqualified stock options and restricted stock units assuming such options and stock units were outstanding common shares at the beginning of the period. The effect of antidilutive securities and performance restricted stock units that have not met vesting criteria are excluded from the computation of diluted earnings per common share.

The following table sets forth the computation of basic and diluted earnings per common share:

	Year Ended December 31,
	2016		2015			2014
(Dollars in millions, except share amounts, in thousands, and per share amounts)
Net income (loss) attributable to Koppers	$	29.3	$	(72.0	)	$	(32.4	)
Less: Income (loss) from discontinued operations		0.6		(0.1	)		0.6
Income (loss) from continuing operations attributable to Koppers	$	28.7	$	(71.9	)	$	(33.0	)
Weighted average common shares outstanding:
Basic		20,636		20,541			20,463
Effect of dilutive securities		419		0			0
Diluted		21,055		20,541			20,463
Earnings (loss) per common share – continuing operations:
Basic earnings (loss) per common share	$	1.39	$	(3.50	)	$	(1.61	)
Diluted earnings (loss) per common share		1.36		(3.50	)		(1.61	)
Other data:
Antidilutive securities excluded from computation of diluted earnings per common share		415		688			362

Stock-based Compensation

12 Months Ended

Dec. 31, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-based Compensation

8. Stock-based Compensation

The amended and restated 2005 Long-Term Incentive Plan (the “LTIP”) provides for the grant to eligible persons of stock options, stock appreciation rights, restricted stock, restricted stock units, performance shares, performance awards, dividend equivalents and other stock-based awards, which are collectively referred to as the awards.

Restricted Stock Units and Performance Stock Units

Under the LTIP, the board of directors granted restricted stock units and performance stock units to certain employee participants (collectively, the “stock units”). For grants to employees prior to 2015, restricted stock units vest on the third anniversary of the grant date, assuming continued employment by the participant. For the March 2015 and 2016 grants to employees, the restricted stock units vest in four equal annual installments. Restricted stock units that have one-year vesting periods are also issued under the LTIP to members of the board of directors in connection with annual director compensation and, from time to time, are issued to members of management in connection with employee compensation with varying vesting periods.

Compensation expense for non-vested stock units is recorded over the vesting period based on the fair value at the date of grant. The fair value of restricted stock units and performance stock units with a performance condition is the market price of the underlying common stock on the date of grant.

Performance stock units granted prior to 2016 vest based upon a performance condition. These performance stock units generally have three-year performance objectives and all performance stock units have a three-year period for vesting (if the applicable performance objective is achieved). For awards granted prior to 2016, the applicable performance objective is based upon a multi-year cumulative value creation calculation that considers the Company’s financial performance commencing on the first day of each grant year. The number of performance stock units granted represents the target award and participants have the ability to earn between zero and 150 percent or 200 percent (depending on the grant date) of the target award based upon actual performance. If minimum performance criteria are not achieved, no performance stock units will vest.

Performance stock units granted in 2016 vest based upon a market condition. These performance stock units have a three-year performance objective and a three-year period for vesting (if the applicable performance objective is achieved). The applicable performance objective is based on the Company’s total shareholder return (“TSR”) relative to the Standard & Poors SmallCap 600 Materials Index. The number of performance stock units granted represents the target award and participants have the ability to earn between zero and 200 percent of the target award based upon actual performance. If minimum performance criteria are not achieved, no performance stock units will vest. The Company has the discretion to settle the award in cash rather than shares, although the Company currently expects that all awards will be settled by the issuance of shares.

Compensation expense for non-vested performance stock units with a market condition is recorded over the vesting period based on the fair value at the date of grant. The Company calculated the fair value of the awards on the date of grant using the Monte Carlo valuation model and the assumptions listed below:

	March 2016 Grant
Grant date price per share of performance award	$	18.11
Expected dividend yield per share		0.00	%
Expected volatility		40.86	%
Risk-free interest rate		0.96	%
Look-back period in years		2.84
Grant date fair value per share of performance award	$	23.70

Dividends declared, if any, on the Company’s common stock during the period prior to vesting of the stock units are credited at equivalent value as additional stock units and become payable as additional common shares upon vesting. In the event of termination of employment, other than retirement, death or disability, any non-vested stock units are forfeited, including additional stock units credited from dividends. In the event of termination of employment due to retirement, death or disability, pro-rata vesting of the stock units over the service period will result. There are special vesting provisions for the stock units related to a change in control.

The following table shows a summary of the performance stock units as of December 31, 2016:

Performance Period	Minimum Shares		Target Shares		Maximum Shares
2014 – 2016		0		87,262		130,893
2015 – 2017		0		203,953		407,906
2016 – 2018		0		260,588		521,176

The following table shows a summary of the status and activity of non-vested stock awards for the year ended December 31, 2016:

	Restricted Stock Units			Performance Stock Units			Total Stock Units			Weighted Average Grant Date Fair Value per Unit
Non-vested at January 1, 2016		213,208			397,399			610,607		$	27.29
Granted		178,282			264,981			443,263		$	22.25
Credited from dividends		950			1,712			2,662		$	25.47
Vested		(100,281	)		0			(100,281	)	$	28.77
Forfeited		(12,352	)		(109,704	)		(122,056	)	$	36.46
Non-vested at December 31, 2016		279,807			554,388			834,195		$	23.09

Compensation expense for non-vested performance stock units with a market condition is recorded over the vesting period based on the fair value at the date of grant.

Stock Options

Prior to 2015, stock options to most executive officers vest and become exercisable upon the completion of a three-year service period commencing on the grant date. For the 2015 and 2016 grants, the stock options vest in four equal annual installments. The stock options have a term of 10 years. In the event of termination of employment, other than retirement, death or disability, any non-vested options are forfeited. In the event of termination of employment due to retirement, death or disability, pro-rata vesting of the options over the service period will result. There are special vesting provisions for the stock options related to a change in control.

Compensation expense for non-vested stock options is recorded over the vesting period based on the fair value at the date of grant. The Company calculated the fair value of stock options on the date of grant using the Black-Scholes-Merton model and the assumptions listed below:

	March 2016 Grant			March 2015 Grant			February 2014 Grant
Grant date price per share of stock option award	$	18.11		$	17.57		$	37.93
Expected dividend yield per share		0.00	%		3.40	%		2.75	%
Expected life in years		5.96			5.75			6.5
Expected volatility		40.86	%		42.27	%		52.14	%
Risk-free interest rate		1.45	%		1.73	%		1.98	%
Grant date fair value per share of option awards	$	7.41		$	5.20		$	15.26

The dividend yield is based on the Company’s current and prospective dividend rate which calculates a continuous dividend yield based upon the market price of the underlying common stock. The Company suspended its dividend in February 2015 and does not expect to declare any dividends for the foreseeable future. The expected life in years for the March 2016 and 2015 grants is based on historical exercise data of options previously granted by the Company. The expected life in years for grants prior to 2015 are based on the simplified method permitted under Securities and Exchange Commission Staff Accounting Bulletin Topic 14 which calculates the average of the weighted vesting term and the contractual term of the option. This method was selected due to the lack of historical exercise data with respect to the Company at the time of those grants. Expected volatility is based on the historical volatility of the Company’s common stock and the historical volatility of certain other similar public companies. The risk-free interest rate is based on U.S. Treasury bill rates for the expected life of the option.

The following table shows a summary of the status and activity of stock options for the year ended December 31, 2016:

	Options			Weighted Average Exercise Price per Option		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in millions)
Outstanding at December 31, 2015		774,249		$	28.46
Granted		211,193		$	18.11
Exercised		(15,901	)	$	24.94
Expired		(14,548	)	$	40.38
Forfeited		(19,539	)	$	23.70
Outstanding at December 31, 2016		935,454		$	26.10		6.46	$	6.0
Exercisable at December 31, 2016		436,582		$	33.07		4.14	$	3.3

Total stock-based compensation expense recognized and cash received from the exercise of stock options for the three years ended December 31, 2016, 2015 and 2014 are as follows:

	Year Ended December 31,
	2016		2015		2014
(Dollars in millions)
Stock-based compensation expense recognized:
Selling, general and administrative expenses	$	8.9	$	3.8	$	4.7
Less related income tax benefit		3.6		1.5		1.9
Decrease in net income attributable to Koppers	$	5.3	$	2.3	$	2.8
Intrinsic value of exercised stock options	$	0.1	$	0.0	$	0.3
Cash received from the exercise of stock options	$	0.4	$	0.0	$	0.7

As of December 31, 2016 total future compensation expense related to non-vested stock-based compensation arrangements totaled $12.0 million and the weighted-average period over which this expense is expected to be recognized is approximately 25 months.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References + Details

Segment Information

12 Months Ended

Dec. 31, 2016

Segment Reporting [Abstract]

Segment Information

9. Segment Information

The Company has three reportable segments: Railroad and Utility Products and Services, Carbon Materials and Chemicals, and Performance Chemicals. The Company’s reportable segments contain multiple business units since management believes the long-term financial performance of these business units is affected by similar economic conditions. The reportable segments are each managed separately because they manufacture and distribute distinct products with different production processes.

The Company’s Railroad and Utility Products and Services segment sells treated and untreated wood products, manufactured products and services primarily to the railroad and public utility markets. Railroad products and services include procuring and treating items such as crossties, switch ties and various types of lumber used for railroad bridges and crossings and the manufacture of rail joint bars. We also operate a railroad services business that conducts engineering, design, repair and inspection services for railroad bridges. Utility products include transmission and distribution poles and pilings.

The Company’s Carbon Materials and Chemicals segment is primarily a manufacturer of creosote, carbon pitch, naphthalene, phthalic anhydride and carbon black feedstock. Creosote is used in the treatment of wood and carbon black feedstock is used in the production of carbon black. Carbon pitch is a critical raw material used in the production of aluminum and for the production of steel in electric arc furnaces. Naphthalene is used for the production of phthalic anhydride and as a surfactant in the production of concrete. Phthalic anhydride is used in the production of plasticizers, polyester resins and alkyd paints.

The Company’s Performance Chemicals segment develops, manufactures, and markets wood preservation chemicals and wood treatment technologies and services a diverse range of end-markets including infrastructure, residential and commercial construction, and agriculture.

The Company evaluates performance and determines resource allocations based on a number of factors, the primary measure being operating profit or loss from operations. Operating profit does not include equity in earnings of affiliates, other income, interest expense or income taxes. Operating profit also excludes the operating costs of Koppers Holdings Inc., the parent company of Koppers Inc. The accounting policies of the reportable segments are the same as those described in the summary of significant accounting policies. Intersegment transactions are eliminated in consolidation.

The following table sets forth certain sales and operating data, net of all intersegment transactions, for the Company’s segments for the periods indicated:

	Year Ended December 31,
	2016			2015			2014
(Dollars in millions)
Revenues from external customers:
Railroad and Utility Products and Services	$	586.5		$	657.0		$	597.8
Carbon Materials and Chemicals		436.3			613.4			833.7
Performance Chemicals		393.4			356.5			123.5
Total	$	1,416.2		$	1,626.9		$	1,555.0
Intersegment revenues:
Carbon Materials and Chemicals	$	90.2		$	86.7		$	84.8
Performance Chemicals		8.1			8.7			3.0
Total	$	98.3		$	95.4		$	87.8
Depreciation and amortization expense:
Railroad and Utility Products and Services^(a)	$	13.0		$	14.2		$	11.9
Carbon Materials and Chemicals^(b)		21.2			25.8			25.0
Performance Chemicals		18.7			19.0			7.1
Total	$	52.9		$	59.0		$	44.0
Operating profit (loss):
Railroad and Utility Products and Services^(c)	$	51.1		$	62.2		$	53.6
Carbon Materials and Chemicals^(d)		(25.1	)		(125.0	)		(5.3	)
Performance Chemicals		62.0			39.0			1.6
Corporate^(e)		(1.6	)		(5.8	)		(16.7	)
Total	$	86.4		$	(29.6	)	$	33.2
Capital expenditures (including acquisitions):
Railroad and Utility Products and Services	$	11.2		$	11.1		$	44.5
Carbon Materials and Chemicals		29.5			37.6			63.7
Performance Chemicals		7.9			5.8			471.1
Corporate		1.3			1.5			0.7
Total	$	49.9		$	56.0		$	580.0

(a)	Excludes impairment charges of $1.9 million in 2015 for a wood treating facility in the United States.

(b) Excludes impairment charges of $3.5, $12.8 and $4.7 million in 2016, 2015 and 2014, respectively, for CMC.

(c) Includes asset retirement obligation and other restructuring costs of $6.9 million for the restructuring of three facilities in the United States in 2016. Includes gain on sale of the Company’s North American utility pole business of $3.2 million and restructuring costs of $5.7 million for a wood treating facility in the United States in 2015.

(d)	Includes plant closure costs of $13.2, $36.5 and $18.1 million in 2016, 2015 and 2014, respectively, for CMC. In the fourth quarter of 2015, the Company also recorded goodwill impairment charges of $67.2 million related to this business unit.

(e)

Operating loss for Corporate includes general and administrative costs for Koppers Holdings Inc., the parent company of Koppers Inc., foreign exchange revaluation related to intercompany loans in connection with a legal reorganization of the Company and acquisition and acquisition-related integration costs.

The following table sets forth tangible and intangible assets allocated to each of the Company’s segments as of the dates indicated:

	December 31, 2016		December 31, 2015
(Dollars in millions)
Segment assets:
Railroad and Utility Products and Services	$	264.2	$	254.1
Carbon Materials and Chemicals		333.0		368.4
Performance Chemicals		442.9		441.3
Segment assets		1,040.1		1,063.8
Cash and cash equivalents		0.0		0.1
Income tax receivable		3.8		4.6
Deferred taxes		32.5		32.6
Property, plant and equipment, net		4.9		4.7
Deferred charges		0.7		1.6
Other		5.5		5.4
Total	$	1,087.5	$	1,112.9
Goodwill:
Railroad and Utility Products and Services	$	9.9	$	9.9
Performance Chemicals		176.5		176.7
Total	$	186.4	$	186.6

Revenues and Long-lived Assets by Geographic Area

	Year		Revenue		Long-lived assets
(Dollars in millions)
United States		2016	$	929.3	$	446.6
		2015		991.2		460.3
		2014		833.0		518.8
Australasia		2016		228.4		124.3
		2015		280.9		132.9
		2014		349.0		160.3
Europe		2016		140.2		31.9
		2015		144.0		32.9
		2014		201.1		47.5
Other countries		2016		118.3		19.5
		2015		210.8		18.3
		2014		171.9		18.3
Total		2016	$	1,416.2	$	622.3
		2015	$	1,626.9	$	644.5
		2014	$	1,555.0	$	744.9

Revenues by geographic area in the above table are attributed by the destination country of the sale. Revenues from non-U.S. countries totaled $486.9 million in 2016, $635.7 million in 2015 and $722.0 million in 2014.

Segment Revenues for Significant Product Lines

	Year Ended December 31,
	2016		2015		2014
(Dollars in millions)
Railroad and Utility Products and Services:
Railroad crossties	$	374.0	$	422.0	$	371.4
Utility poles		34.5		52.4		96.1
Creosote		49.6		45.7		51.2
Rail joints		24.4		28.1		27.2
Railroad infrastructure services		43.4		42.7		14.8
Other products		60.6		66.1		37.1
		586.5		657.0		597.8
Carbon Materials and Chemicals:
Carbon pitch		191.0		283.4		330.2
Phthalic anhydride		75.6		65.1		91.4
Creosote and carbon black feedstock		71.3		119.6		213.7
Other products		98.4		145.3		198.4
		436.3		613.4		833.7
Performance Chemicals:
Wood preservative products		365.5		318.6		107.0
Other products		27.9		37.9		16.5
		393.4		356.5		123.5
Total	$	1,416.2	$	1,626.9	$	1,555.0

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8981-108599

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e9038-108599

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8971-108599

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8595-108599

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8380-108599

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8933-108599

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 26
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8844-108599

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 35
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8984-108599

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e9031-108599

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e9054-108599

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8538-108599

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 29
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8864-108599

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8924-108599

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8906-108599

+ Details

Income Taxes

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Income Taxes

10. Income Taxes

Income Tax Provision

Components of the Company’s income tax provision from continuing operations are as follows:

	Year Ended December 31,
	2016			2015			2014
(Dollars in millions)
Current:
Federal	$	(1.9	)	$	(4.2	)	$	17.5
State		1.3			0.2			0.3
Foreign		13.3			16.0			14.6
Total current tax provision		12.7			12.0			32.4
Deferred:
Federal		(1.6	)		(19.2	)		3.1
State		0.5			3.0			0.0
Foreign		(0.2	)		0.0			(1.4	)
Total deferred tax (benefit) provision		(1.3	)		(16.2	)		1.7
Total income tax (benefit) provision	$	11.4		$	(4.2	)	$	34.1

Income (loss) before income taxes for 2016, 2015 and 2014 included $48.2 million, $(15.2) million and $(1.5) million, respectively, from foreign operations.

The provision for income taxes is reconciled with the federal statutory rate as follows:

	Year Ended December 31,
	2016			2015			2014
Federal income tax rate		35.0	%		35.0	%		35.0	%
State income taxes, net of federal tax benefit		(0.8	)		2.3			(4.8	)
Foreign earnings taxed at different rates		(10.1	)		(8.3	)		(347.6	)
Domestic production activities deduction	0.0				(0.6	)		40.8
Deferred tax adjustments		(0.2	)		0.4			3.2
Change in tax contingency reserves		6.5			1.5			(15.2	)
Legal entity tax restructuring project	0.0			0.0				(1,503.2	)
Foreign tax credits	0.0			0.0				1,203.4
Changes to foreign repatriation plans	0.0			0.0				104.0
Valuation allowance charges		(1.9	)		(13.0	)		(92.4	)
Goodwill impairment	0.0				(10.9	)	0.0
Other		1.1			(1.1	)		(1.2	)
		29.6	%		5.3	%		(578.0	%)

The Company has not provided a U.S. deferred tax liability on the difference between the financial reporting and tax basis of its investments in its foreign subsidiaries, except for an immaterial amount of unremitted foreign earnings that are expected to be remitted as a dividend. Where the tax basis of these investments exceeds the financial reporting basis, the Company does not anticipate it will dispose of these foreign subsidiaries in the foreseeable future and, as such, has not recognized a U.S. deferred tax asset for this excess tax basis. To the extent such foreign subsidiaries may also have unremitted earnings, such earnings have either been previously taxed in the U.S. or are considered to be indefinitely reinvested. Where the financial reporting basis of these investments exceeds its tax basis, substantially all of the basis difference is attributable to unremitted earnings that are considered to be indefinitely reinvested. At December 31, 2016, there was approximately $85 million of such unremitted earnings which would be taxed if they were remitted as a dividend. To estimate the amount of taxes that may be payable when these earnings are remitted in the future, many assumptions, such as the tax profile of the Company at that time and the availability of potential U.S. foreign tax credits that may reduce the ultimate amount of tax, are required. Therefore, it is not practicable to estimate the amount of taxes that may be payable when these earnings are remitted in the future.

Taxes Excluded from Net Income Attributable to Koppers

The amount of income tax expense (benefit) included in comprehensive income (loss) but excluded from net income attributable to Koppers relating to adjustments to copper swap contracts is $8.0 million, $(1.2) million, and $(2.6) million for the years ended December 31, 2016, 2015, and 2014, respectively.

The amount of income tax expense (benefit) included in comprehensive income (loss) but excluded from net income attributable to Koppers relating to adjustments to reflect the unfunded status of employee post-retirement benefit plans is $2.0 million, $0.6 million, and $(8.1) million for the years ended December 31, 2016, 2015, and 2014, respectively.

The amount of income tax expense included in shareholders’ equity but excluded from net income attributable to Koppers relating to the expense for restricted stock and employee stock options recognized differently for financial and tax reporting purposes is $0.4 million, $0.5 million and $0.3 million for the years ended December 31, 2016, 2015, and 2014, respectively.

Deferred Tax Assets and Liabilities

Deferred income taxes reflect the net tax effects of differences between the carrying amounts of assets and liabilities for financial reporting purposes and for income tax purposes.

Significant components of the Company’s deferred tax assets and liabilities are as follows:

	Year Ended December 31,
	2016			2015
(Dollars in millions)
Deferred tax assets:
Reserves, including insurance, environmental and deferred revenue	$	22.3		$	19.9
Pension and other postretirement benefits obligations		19.2			19.4
Tax credits		15.4			16.8
Asset retirement obligations		12.0			12.0
State tax losses carryforwards (expiring from 2017-2036)		11.3			10.2
Foreign tax loss carryforwards (expiring beginning in 2018)		10.1			9.3
Accrued employee compensation		8.9			6.9
Book/tax inventory accounting differences		3.5			3.2
Capital loss benefit		0.0			0.9
Book over tax depreciation and amortization		0.0			3.6
Other		6.6			10.0
Valuation allowance		(40.2	)		(41.9	)
Total deferred tax assets		69.1			70.3
Deferred tax liabilities:
Tax over book depreciation and amortization		42.7			38.4
Gain on derivative contracts		4.2			0.0
Tax/book inventory accounting differences		0.0			0.3
Other		1.4			0.7
Total deferred tax liabilities		48.3			39.4
Net deferred tax assets	$	20.8		$	30.9

A valuation allowance is necessary when it is more likely than not that a deferred tax asset will not be realized. Certain deferred tax assets reflected above are not expected to be realized and a valuation allowance has been provided for them. Valuation allowances are recorded to offset the following deferred tax assets:

	Year Ended December 31,
	2016		2015
Federal foreign tax credits	$	14.3	$	14.9
State temporary differences, net operating losses and tax credits		13.2		11.6
Foreign temporary differences, net operating losses and capital losses		12.7		15.4
Total valuation allowances	$	40.2	$	41.9

During 2016, the Company generated additional net operating losses in certain states which require each legal entity to file a separate return. As it is not expected that certain entities will generate future taxable income to realize the benefit of these losses, the related valuation allowance was increased by $1.6 million. Also, a valuation allowance of $2.1 million provided in 2015 on certain United Kingdom deferred tax assets associated with the closure of manufacturing facilities was released during 2016. After the sale of assets and transfer of liabilities to a third party in 2016, it became apparent that remaining future deductions will be available to offset taxable income generated by other of our United Kingdom entities.

Management evaluated the ability to realize remaining deferred tax assets, particularly in light of the financial reporting losses reported over the preceding three years. As discussed in Note 14, “Goodwill and Other Identifiable Intangible Assets,” the Company incurred a goodwill impairment charge in 2015 of $67.2 million, of which $25.1 million related to nondeductible goodwill which was the primary factor contributing to the three-year cumulative loss. Excluding these nonrecurring charges, Management has concluded that the Company will generate sufficient future taxable income in periods when these deferred tax assets become deductible.

Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:

	Year Ended December 31,
	2016			2015			2014
(Dollars in millions)
Balance at beginning of year	$	7.7		$	7.2		$	6.1
Additions based on tax provisions related to the current year		0.9			1.4			0.6
Additions for tax provisions of prior years		1.5			0.0			0.1
Additions as a result of acquisitions		0.0			0.0			1.6
Reductions of tax provisions of prior years		0.0			(0.7	)		(0.6	)
Reductions as a result of a lapse of the applicable statute of limitations		(0.4	)		(0.2	)		(0.6	)
Balance at end of year	$	9.7		$	7.7		$	7.2

As of December 31, 2016 and 2015, the total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate, was approximately $5.7 million and $4.1 million, respectively.

The Company recognizes interest expense (income) and any related penalties from unrecognized tax benefits in income tax expense. For the years ended December 31, 2016, 2015, and 2014, the Company recognized $1.2 million, $(1.5) million and $1.5 million, respectively, in interest and penalties. As of December 31, 2016 and 2015, the Company had accrued interest and penalties of approximately $4.2 million and $1.2 million, respectively.

The Company believes that it is reasonably possible that the amount of unrecognized tax benefits will decrease in the next twelve months by approximately $3 million due to the expirations of certain foreign and state statutes of limitations and potential audit resolutions. The Company does not anticipate significant increases to the amount of unrecognized tax benefits within the next twelve months.

The Company and its subsidiaries file income tax returns in U.S. federal jurisdiction, individual U.S. state jurisdictions and non-U.S. jurisdictions. With few exceptions, the Company is no longer subject to U.S. federal, U.S. state, or non-U.S. income tax examinations by tax authorities for years before 2011.

Inventories

12 Months Ended

Dec. 31, 2016

Inventory Disclosure [Abstract]

Inventories

11. Inventories

Inventories as of December 31, 2016 and 2015 were as follows:

	December 31, 2016		December 31, 2015
(Dollars in millions)
Raw materials	$	157.7	$	169.8
Work in process		14.2		15.5
Finished goods		103.6		97.4
		275.5		282.7
Less revaluation to LIFO		46.8		56.3
Net	$	228.7	$	226.4

Equity Investments

12 Months Ended

Dec. 31, 2016

Equity Method Investments And Joint Ventures [Abstract]

Equity Investments

12. Equity Investments

The Company has no remaining investments in unconsolidated companies as of December 31, 2016. During 2016, the Company sold its 30 percent interest in TKK. See additional information regarding TKK in Note 5 “Related Party Transactions.” During 2015, the Company sold the assets of KSA Limited Partnership for $2.5 million to a third party resulting in a gain of $0.3 million. KSA Limited Partnership was a 50 percent-owned concrete crosstie operation. No dividends were paid for the three years ended December 31, 2016. Equity in losses for the three years ended December 31, 2016 were as follows:

	Equity loss
(Dollars in millions)
2016	$	(1.0	)
2015		(2.2	)
2014		(1.6	)

Property, Plant and Equipment

12 Months Ended

Dec. 31, 2016

Property Plant And Equipment [Abstract]

Property, Plant and Equipment

13. Property, Plant and Equipment

Property, plant and equipment as of December 31, 2016 and 2015 were as follows:

	December 31, 2016		December 31, 2015
(Dollars in millions)
Land	$	17.0	$	17.6
Buildings		58.2		61.8
Machinery and equipment		716.0		669.0
	$	791.2	$	748.4
Less accumulated depreciation		510.4		470.6
Net	$	280.8	$	277.8

Depreciation expense, including impairment charges, for the years ended December 31, 2016, 2015 and 2014 amounted to $41.6 million, $58.4 million and $38.8 million, respectively.

Impairments – Impairment charges for 2016, 2015 and 2014 were $3.5 million, $14.7 million and $4.7 million, respectively. In 2016, impairment charges primarily related to the decision to discontinue coal tar distillation activities at a CMC plant located in the United States.

The 2015 impairment charges primarily related to the decision to discontinue coal tar distillation activities at CMC plants located in the United Kingdom and the United States. The remaining 2015 impairment charges were related to the RUPS wood treating plant in Green Spring, West Virginia.

The 2014 impairment charges primarily related to the CMC plant in Tangshan, China ($2.8 million, net of non-controlling interest). These impairment charges were calculated using a probability-weighted discounted cash flow model.

Goodwill and Other Identifiable Intangible Assets

12 Months Ended

Dec. 31, 2016

Goodwill And Intangible Assets Disclosure [Abstract]

Goodwill and Other Identifiable Intangible Assets

14. Goodwill and Other Identifiable Intangible Assets

The change in the carrying amount of goodwill attributable to each business segment for the years ended December 31, 2016 and December 31, 2015 was as follows:

	Carbon Materials and Chemicals			Railroad and Utility Products and Services			Performance Chemicals			Total
(Dollars in millions)
Balance at December 31, 2014	$	65.5		$	9.3		$	172.4		$	247.2
Acquisitions		4.1			0.0			0.0			4.1
Purchase price allocation adjustments		0.0			1.2			8.3			9.5
Impairment		(67.2	)		0.0			0.0			(67.2	)
Currency translation		(2.4	)		(0.6	)		(4.0	)		(7.0	)
Balance at December 31, 2015	$	0.0		$	9.9		$	176.7		$	186.6
Currency translation		0.0			0.0			(0.2	)		(0.2	)
Balance at December 31, 2016	$	0.0		$	9.9		$	176.5		$	186.4

Goodwill represents the excess of the cost over the fair value of acquired identifiable tangible and intangible assets and liabilities assumed from businesses acquired.

Goodwill is tested for impairment at the reporting unit level annually in the fourth quarter and whenever events or circumstances indicate the carrying value may not be recoverable. The evaluation of goodwill impairment involves using either a qualitative or quantitative approach as outlined in ASC Topic 350. In the fourth quarter of 2016 and 2014, the Company determined that the estimated fair values substantially exceeded the carrying values of all the reporting units, and accordingly, there was no impairment of goodwill for the year ended December 31, 2016 and for the year ended December 31, 2014.

During the fourth quarter of 2015, the Company completed its annual goodwill impairment evaluation using the two-step quantitative analysis. In the first step of the analysis, the Company compared the estimated fair value of each reporting unit to its carrying value, including goodwill. The fair value of the reporting units was determined based on a weighting of income and market approaches. Since the carrying value of the CMC reporting unit exceeded the fair value, the Company performed the second step of the impairment analysis in order to determine the implied fair value of the reporting unit’s goodwill. The implied fair value of goodwill represents the excess of fair value of the reporting unit over the fair value amounts assigned to all of the assets and liabilities of the reporting unit as if it were to be acquired in a business combination and the current fair value of the reporting unit (as calculated in the first step) was the purchase price. Any amount remaining after this allocation represents the implied fair value of goodwill.

The implied fair value of the respective reporting unit’s goodwill was then compared to the carrying value of the goodwill and any excess of carrying value over the implied fair value represents the non-cash impairment charge. The results of the second step analysis showed that the implied fair value of goodwill was zero for the CMC reporting unit. Therefore, in 2015, the Company recorded a goodwill impairment charge of $67.2 million for the CMC reporting unit. During the fourth quarter of 2015, the Company observed certain negative factors including a declining market capitalization, downsizing of the global aluminum markets and continued decline in spot and forward oil pricing. As noted elsewhere in this Form 10-K, the Company and its board of directors approved certain strategic changes for the CMC reporting unit during the fourth quarter of 2015 reflecting the current market environment. The aforementioned negative factors all severely impact the outlook and corresponding fair value for the Company’s CMC reporting unit and were the primary factors for the goodwill impairment charge recorded during the fourth quarter of 2015. As a result of the goodwill impairment charge, there is no goodwill remaining for the CMC reporting unit as of December 31, 2015.

For purposes of the income approach, fair value was determined based on the present value of estimated future cash flows, discounted at an appropriate risk-adjusted rate (DCF analysis). The Company made assumptions about the amount and timing of future expected cash flows, terminal value growth rates and appropriate discount rates. The amount and timing of future cash flows within the Company’s DCF analysis was based on its most recent operational budgets, long range strategic plans and other estimates. A one half of one percent perpetual growth rate was used to calculate the value of cash flows beyond the last projected period in the Company’s DCF analysis for the CMC reporting unit and reflects its best estimates for stable, perpetual growth of its reporting unit. Actual results may differ from those assumed in the Company’s forecasts. The Company used estimates of market participant weighted average cost of capital as a basis for determining the discount rate of 14 percent applied to the CMC reporting unit’s future expected cash flows, adjusted for risks and uncertainties inherent in the chemical industry and in its internally developed forecasts.

The market approach is based upon an analysis of valuation metrics for companies comparable to the reporting unit. The fair value for the CMC reporting unit was estimated using an appropriate valuation multiple, as well as estimated normalized earnings and an estimated control premium.

In order to further validate the reasonableness of the estimated fair values of the reporting units as of the valuation date in the fourth quarter of 2015, a reconciliation of the aggregate fair values of all reporting units to the Company’s market capitalization was performed using a reasonable control premium.

Goodwill impairment tests in years prior to December 31, 2015 indicated that goodwill was not impaired for any of the Company’s reporting units. Accumulated impairment losses totaled $67.2 million as of December 31, 2016 and 2015.

The Company’s identifiable intangible assets with finite lives are being amortized over their estimated useful lives and are summarized below:

					December 31,
					2016						2015
	Estimated life in years		Weighted average remaining life in years		Gross Carrying Amount		Accumulated Amortization		Net		Gross Carrying Amount		Accumulated Amortization		Net
(Dollars in millions)
Customer contracts	9 to 18			13.2	$	152.5	$	33.6	$	118.9	$	153.0	$	24.3	$	128.7
Technology	4 to 12			5.0		26.7		8.8		17.9		26.6		5.1		21.5
Trademarks	4 to 7			4.6		6.1		1.9		4.2		5.9		1.1		4.8
Supply contracts		10		3.2		2.2		1.5		0.7		2.3		1.4		0.9
Non-compete agreements		12		7.8		1.3		1.1		0.2		1.4		1.2		0.2
Favorable lease agreements		3		0.0		0.6		0.6		0.0		0.7		0.7		0.0
Total				11.9	$	189.4	$	47.5	$	141.9	$	189.9	$	33.8	$	156.1

In 2016, the gross carrying value of identifiable intangible assets decreased by $0.5 million due to foreign currency translation. Total amortization expense related to these identifiable intangible assets was $14.8 million, $15.3 million and $8.4 million for the years ended December 31, 2016, 2015 and 2014, respectively. Estimated amortization expense for the next five years is summarized below:

	Estimated annual amortization
(Dollars in millions)
2017	$	14.3
2018		14.3
2019		14.3
2020		14.0
2021		12.1

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Pensions and Post-Retirement Benefit Plans

12 Months Ended

Dec. 31, 2016

Compensation And Retirement Disclosure [Abstract]

Pensions and Post-Retirement Benefit Plans

15. Pensions and Post-Retirement Benefit Plans

The Company and its subsidiaries maintain a number of defined benefit and defined contribution plans to provide retirement benefits for employees in the U.S., as well as employees outside the U.S. These plans are maintained and contributions are made in accordance with the Employee Retirement Income Security Act of 1974 (“ERISA”), local statutory law or as determined by the board of directors. The defined benefit pension plans generally provide benefits based upon years of service and compensation. Pension plans are funded except for three domestic non-qualified defined benefit pension plans for certain key executives.

In the U.S., all qualified defined benefit pension plans for salaried and hourly employees have been closed to new participants and have been frozen. Accordingly, these pension plans no longer accrue additional years of service or recognize future increases in compensation for benefit purposes.

The defined contribution plans generally provide retirement assets to employee participants based upon employer and employee contributions to the participant’s individual investment account. The Company also provides retiree medical insurance coverage to certain U.S. employees and a life insurance benefit to most U.S. employees. For salaried employees, the retiree medical and retiree insurance plans have been closed to new participants.

In the third quarter of 2016, the Company offered a cash lump sum or annuity buyout to its terminated deferred vested participants in its U.S. defined benefit pension plan. Approximately 375 participants elected either a lump sum payout or annuity from a third party provider. The total dollar amount paid out of our defined benefit plan assets was $13.9 million and the Company recorded a pension settlement charge of $4.4 million for the year ended December 31, 2016.

Expense related to defined contribution plans totaled $7.8 million, $6.0 million and $6.9 million for the years ended December 31, 2016, 2015 and 2014, respectively.

Net periodic pension costs for 2016, 2015 and 2014 were as follows:

	December 31,
	Pension Benefits									Other Benefits
	2016			2015			2014			2016			2015			2014
(Dollars in millions)
Service cost	$	1.7		$	2.0		$	2.7		$	0.1		$	0.1		$	0.1
Interest cost		11.0			10.9			11.8			0.4			0.4			0.5
Expected return on plan assets		(10.5	)		(12.0	)		(13.9	)		0.0			0.0			0.0
Amortization of prior service cost		0.0			(0.3	)		(0.2	)		0.0			(0.1	)		(0.2	)
Amortization of net loss		2.2			6.6			4.0			(0.4	)		(0.3	)		0.0
Settlements and curtailments		4.4			(0.8	)		0.0			0.0			0.0			0.0
Net periodic benefit cost	$	8.8		$	6.4		$	4.4		$	0.1		$	0.1		$	0.4

Net periodic pension cost is expected to be recognized from the amortization of net loss and is estimated to total $2.0 million for all plans in 2017.

The change in the funded status of the pension and postretirement plans as of December 31, 2016 and December 31, 2015 is as follows:

	December 31,
	Pension Benefits						Other Benefits
	2016			2015			2016			2015
(Dollars in millions)
Change in benefit obligation:
Benefit obligation at beginning of year	$	257.5		$	275.7		$	9.4		$	9.8
Service cost		1.7			2.0			0.1			0.1
Interest cost		11.0			10.9			0.4			0.4
Plan participants’ contributions		0.1			0.2			0.0			0.0
Actuarial losses (gains)		10.7			(14.9	)		1.0			(0.3	)
Plan amendments		(0.1	)		0.0			0.0			0.0
Settlements		(13.9	)		0.0			0.0			0.0
Currency translation		(9.9	)		(3.4	)		0.0			0.0
Benefits paid		(13.5	)		(13.0	)		(0.9	)		(0.6	)
Benefit obligation at end of year		243.6			257.5			10.0			9.4
Change in plan assets:
Fair value of plan assets at beginning of year		212.4			229.5			0.0			0.0
Actual return on plan assets		20.8			(4.6	)		0.0			0.0
Employer contribution		4.4			3.4			0.9			0.6
Plan participants’ contributions		0.1			0.2			0.0			0.0
Settlements		(13.9	)		0.0			0.0			0.0
Currency translation		(9.4	)		(3.1	)		0.0			0.0
Benefits paid		(13.5	)		(13.0	)		(0.9	)		(0.6	)
Fair value of plan assets at end of year		200.9			212.4			0.0			0.0
Funded status of the plan	$	(42.7	)	$	(45.1	)	$	(10.0	)	$	(9.4	)
Amounts recognized in the balance sheet consist of:
Noncurrent assets	$	0.8		$	0.8		$	0.0		$	0.0
Current liabilities		1.1			0.9			0.8			0.8
Noncurrent liabilities		42.4			45.0			9.2			8.6
Pension plans with projected benefit obligations in excess of plan assets:
Benefit obligation	$	238.7		$	252.7
Fair value of plan assets		195.3			206.9
Pension plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligation	$	238.5		$	251.2
Fair value of plan assets		195.3			206.9

The measurement date for all pension and postretirement assets and obligations is December 31 for each respective year.

The accumulated benefit obligation for all defined benefit pension plans as of December 31, 2016 and 2015 was $243.3 million and $255.8 million, respectively.

Expected Contributions for the 2017 Fiscal Year

The expected contributions by the Company for 2017 are estimated to be $4.2 million for pension plans and $0.8 million for other benefit plans.

Projected Benefit Payments

Benefit payments for pension benefits, which are primarily funded by the pension plan assets, and other benefits, which are funded by general corporate assets and reflecting future expected service as appropriate, are expected to be paid as follows:

	Pension Benefits		Other Benefits
(Dollars in millions)
2017	$	13.0	$	0.9
2018		12.9		0.9
2019		13.2		0.8
2020		13.5		0.8
2021		13.8		0.7
Next five years		75.0		3.1

Weighted-Average Assumptions as of December 31

	December 31,
	Pension Benefits						Other Benefits
	2016			2015			2016			2015
Discount rate		4.09	%		4.52	%		4.53	%		4.73	%
Expected return on plan assets		5.10			5.16
Rate of compensation increase		3.50			3.82
Initial medical trend rate								6.30			6.50

Basis for the Selection of the Long-Term Rate of Return on Assets

The long-term rate of return on assets assumption was determined by using the plan’s asset allocation as described in the plan’s investment policy and modeling a distribution of compound average returns over a time horizon. The model uses asset class return, variance, and correlation assumptions to produce the expected return. The return assumptions used forward looking gross returns influenced by the current bond yields, corporate bond spreads and equity risk premiums based on current market conditions.

In general, the long-term rate of return is the sum of the portion of total assets in each asset class multiplied by the expected return for that class, adjusted for expected expenses to be paid from the assets. To develop the expected long-term rate of return on assets assumption, the Company considered the historical returns and the future expectations for returns for each asset class, as well as the target asset allocation of the pension portfolio.

Investment Strategy

The weighted average asset allocation for the Company’s pension plans at December 31 by asset category is as follows:

	December 31,
	2016			2015
Debt securities		71	%		70	%
Equity securities		24			26
Other		5			4
		100	%		100	%

The Company’s investment strategy for its pension plans is to maintain an adequate level of diversification, to reduce interest rate and market risk and to provide adequate liquidity to meet immediate and future benefit payment requirements. The Company’s overall investment strategy is to achieve a mix of growth seeking assets, principally U.S. and international public company equity securities and income generating assets, principally debt securities, real estate and cash. Currently, the Company targets an allocation of 30 percent to 40 percent growth seeking assets and 60 percent to 70 percent income generating assets on an overall basis. The Company utilizes investment managers to assist in identifying and monitoring investments that meet these allocation criteria. With respect to the U.S defined benefit plan, the Company has implemented a strategy of reallocating pension assets from growth seeking assets to income generating assets as certain funded status levels are reached.

The investment valuation policy of the Company is to value investments at fair value. Most of the assets are invested in pooled or commingled investment vehicles. The Company’s interest in these investment vehicles is expressed as a unit of account with a value per unit that is the result of the accumulated values of the underlying investments. Equity securities held within these investment vehicles are typically priced on a daily basis using the closing market price from the exchange through which the security is traded. Debt securities held within these investment vehicles are typically priced on a daily basis by independent pricing services. The fair value of real estate investments is either priced through a listing on an exchange or are subject to periodic appraisals.

The following table sets forth by level, the Company’s pension plan assets at fair value, within the fair value hierarchy, as of December 31, 2016 and December 31, 2015:

	As of December 31, 2016
	Quoted prices
	in active		Significant		Significant
	markets for		observable		unobservable
	identical assets		inputs		inputs
	(Level 1)		(Level 2)		(Level 3)		Total
(Dollars in millions)
U.S. equity securities	$	12.3	$	13.2		0.0	$	25.5
International equity securities		12.6		10.9		0.0		23.5
U.S. debt securities		29.7		75.2		3.2		108.1
International debt securities		8.3		24.3		1.1		33.7
Real estate and other investments		0.0		0.5		5.7		6.2
Cash and cash equivalents		0.0		3.9		0.0		3.9
	$	62.9	$	128.0	$	10.0	$	200.9

	As of December 31, 2015
	Quoted prices
	in active		Significant		Significant
	markets for		observable		unobservable
	identical assets		inputs		inputs
	(Level 1)		(Level 2)		(Level 3)		Total
(Dollars in millions)
U.S. equity securities	$	15.0	$	10.2	$	0.0	$	25.2
International equity securities	12.1			18.6		0.0	30.7
U.S. debt securities	32.3		84.8			0.0	117.1
International debt securities		7.0	25.5			0.0	32.5
Real estate and other investments		0.0	1.4			0.0	1.4
Cash and cash equivalents		0.0	5.5			0.0	5.5
	$	66.4	$	146.0	$	0.0	$	212.4

The table below sets forth a summary of changes in the fair value of the Level 3 pension plans’ assets for the year ended December 31, 2016:

	As of December 31, 2016
	Other Investments			Debt Securities
(Dollars in millions)
Balance at beginning of year	$	0.0		$	0.0
Purchases, sales, issuances and settlements	4.4				6.0
Realized and unrealized gains	0.2			0.1
Foreign currency translation loss		(0.3	)		(0.4	)
Balance at the end of year	$	4.3		$	5.7
The amount of total gains during the period attributable to the change in unrealized gains relating to Level 3 net assets still held at the reporting date	$	0.2		$	0.1

Health Care Cost Trend Rates

The 2017 initial health care cost trend rate is assumed to be 6.3 percent and is assumed to decrease gradually to 4.5 percent in 2037 and remain at that level thereafter. The assumed health care cost trend rate has a significant effect on the amounts reported for other postretirement benefit liability. A one-percentage-point change in the assumed health care cost trend rate would have the following effects:

	1% Increase		1% Decrease
(Dollars in millions)
Increase (decrease) from change in health care cost trend rates:
Postretirement benefit expense	$	0.0	$	0.0
Postretirement benefit liability		0.2		(0.1	)

Incentive Plan

The Company has short-term management incentive plans that pay cash bonuses if certain Company performance goals are met. The charge to operating expense for these plans was $10.4 million in 2016, $9.2 million in 2015 and $3.8 million in 2014.

Debt

12 Months Ended

Dec. 31, 2016

Debt Disclosure [Abstract]

Debt

16. Debt

Debt at December 31, 2016 and December 31, 2015 was as follows:

	Weighted Average Interest Rate			Maturity	December 31, 2016		December 31, 2015
(Dollars in millions)
Term Loan		4.57	%	2019	$	232.5	$	262.5
Revolving Credit Facility		4.57	%	2019		100.1		130.0
Construction and other loans		4.87	%	2020		40.4		44.8
Senior Notes due 2019		7.88	%	2019		298.1		297.5
Total debt						671.1		734.8
Less short term debt and current maturities of long-term debt						42.6		39.9
Less unamortized debt issuance costs						8.7		12.5
Long-term debt					$	619.8	$	682.4

Events Subsequent to December 31, 2016

As of December 31, 2016, Koppers Inc. had a $300.0 million senior secured revolving credit facility and a $232.5 million senior secured term loan (the “Prior Senior Secured Credit Facilities”) and $298.1 million principal value outstanding of senior notes due 2019 (the “2019 Notes”).

In January 2017, Koppers Inc. completed a private placement offering of $500.0 million 6.00 percent Senior Notes due 2025 (the “2025 Notes”). The 2025 Notes will pay interest semi-annually in arrears on February 15 and August 15 beginning on August 15, 2017 and will mature on February 15, 2025 unless earlier redeemed or repurchased. The 2025 Notes are unsecured and are guaranteed by Koppers Holdings Inc. and certain of Koppers Inc.’s domestic subsidiaries.

Koppers Inc. used the proceeds from the offering of the 2025 Notes to repay its outstanding term loan under the Prior Senior Secured Credit Facilities and to fund a tender offer to repurchase the 2019 Notes. The tender offer for the 2019 Notes was completed in early February 2017. Any 2019 Notes remaining outstanding following the tender offer were called for redemption and Koppers Inc. concurrently satisfied and discharged its remaining obligations under the indenture governing the 2019 Notes.

In February 2017, the Company entered into a new $400.0 million senior secured revolving credit facility (“New Senior Secured Credit Facility”) which replaced the Prior Senior Secured Credit Facilities. The maturity date of the New Senior Secured Credit Facility is February 2022. The interest rate on the New Senior Secured Credit Facility is variable and is based on LIBOR. Terms under the New Senior Secured Credit Facility are substantially consistent with the Prior Senior Secured Credit Facilities.

Prior Senior Secured Credit Facilities

The interest rates on the Prior Senior Secured Credit Facilities’ borrowings were variable and based on LIBOR. The senior secured term loan had quarterly principal repayment obligations of 2.5 percent of the original principal amount borrowed, or $7.5 million.

Borrowings under the revolving credit facility and term loan were secured by a first priority lien on substantially all of the assets of Koppers Inc., Koppers Holdings and their material domestic subsidiaries. The revolving credit facility and term loan contained certain covenants for Koppers Inc. and its restricted subsidiaries that would limit capital expenditures, additional indebtedness, liens, dividends, investments or acquisitions. In addition, such covenants would give rise to events of default upon the failure by Koppers Inc. and its restricted subsidiaries to meet certain financial ratios.

The Company entered into an amendment of the Prior Senior Secured Credit Facilities in April 2016 which reduced the borrowing capacity of its senior secured revolving credit facility to $300.0 million and also amended the leverage ratio covenant requirements. In connection with the amendment, $2.0 million of prior deferred financing costs were required to be written off through interest expense for the year ended December 31, 2016.

As of December 31, 2016, the Company had $159.6 million of unused revolving credit availability for working capital purposes after restrictions from certain letter of credit commitments and other covenants. As of December 31, 2016, $43.5 million of commitments were utilized by outstanding letters of credit.

Construction Loans

On November 18, 2013, the Company’s 75-percent owned subsidiary, Koppers (Jiangsu) Carbon Chemical Company Limited (“KJCC”) entered into two committed loan facility agreements for a combined commitment of RMB 265 million or approximately $44 million. The third party bank provided facility has a commitment amount of RMB 198.8 million and the other committed facility of RMB 66.2 million is provided by the 25-percent non-controlling shareholder in KJCC. Borrowings under the third party bank facility are secured by a letter of credit issued by a bank under the Koppers Inc. revolving credit facility. The committed facilities were used to finance the costs related to the construction of the coal tar distillation plant in Pizhou, Jiangsu province in China.

KJCC will repay the construction loan portion of the third party commitment in six installments every six months starting in June 2018 with a final repayment on December 21, 2020, the maturity date of the loans.

Senior Notes due 2019

The Koppers Inc. 7.88 percent Senior Notes due 2019 (the “2019 Notes”) were issued on December 1, 2009 at an offering price of 98.311 percent of face value, or $294.9 million and had a principal amount at maturity of $300.0 million. The 2019 Notes had an effective interest rate yield of 8.13 percent per annum. The 2019 Notes were fully and unconditionally guaranteed by Koppers Holdings and certain of our wholly-owned domestic subsidiaries, and, as of August 15, 2014, were secured equally and ratably with the obligations under our Prior Senior Secured Credit Facilities. All of the 2019 Notes had been redeemed by February 24, 2017.

Debt Maturities and Deferred Financing Costs

At December 31, 2016 the aggregate debt maturities for the next five years are as follows:


(Dollars in millions)
2017	$	42.6
2018		37.0
2019 ⁽¹⁾		575.3
2020		18.1
Total maturities		673.0
Future accretion on 2019 Notes		(1.9	)
Total debt	$	671.1

(1)	Consists primarily of the maturity of the 2019 Notes and Prior Senior Secured Credit Facilities. The $500.0 million Senior Notes offered in January 2017 mature in 2025. The $400.0 million New Senior Secured Credit Facility entered in February 2017 will mature in 2022.

Unamortized debt issuance costs (net of accumulated amortization of $12.0 million and $6.9 million at December 31, 2016 and 2015, respectively) were $8.7 million and $12.5 million at December 31, 2016 and 2015, respectively, and are included as a deduction from the carrying amount of long-term debt. These costs will be written off in the first quarter of 2017 due to the refinancing of our Prior Senior Secured Credit Facilities and our 2019 Notes.

Leases

12 Months Ended

Dec. 31, 2016

Leases [Abstract]

Leases

17. Leases

Future minimum commitments for operating leases having non-cancelable lease terms in excess of one year are as follows:

(Dollars in millions)
2017	$	43.9
2018		34.0
2019		17.3
2020		13.6
2021		11.7
Thereafter		46.8
Total	$	167.3

Operating lease expense for 2016, 2015 and 2014 was $50.3 million, $46.4 million and $36.7 million, respectively.

Derivative Financial Instruments

12 Months Ended

Dec. 31, 2016

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Derivative Financial Instruments

18. Derivative Financial Instruments

The Company utilizes derivative instruments to manage exposures to risks that have been identified and measured and are capable of being controlled. The primary risks managed by the company by using derivative instruments are commodity price risk associated with copper and foreign currency exchange risk associated with a number of currencies, principally the U.S. dollar, the Canadian dollar, the New Zealand dollar, the Euro and British pounds. Swap contracts on copper are used to manage the price risk associated with forecasted purchases of materials used in the Company’s manufacturing processes. Generally, the Company will not hedge cash flow exposures for durations longer than 30 months and the Company has hedged certain volumes of copper through December 2019. The Company enters into foreign currency forward contracts to manage foreign currency risk associated with the Company’s receivable and payable balances. Generally, the Company enters into master netting arrangements with the counterparties and offsets net derivative positions with the same counterparties. Currently, the Company’s agreements do not require cash collateral.

ASC Topic 815-10, “Derivatives and Hedging,” requires companies to recognize all derivative instruments as either assets or liabilities at fair value in the balance sheet. Derivative instruments’ fair value is determined using significant other observable inputs, or Level 2 in the fair value hierarchy. In accordance with ASC Topic 815-10, the Company designates certain of its commodity swaps as cash flow hedges of forecasted purchases of commodities. For derivative instruments that are designated and qualify as cash flow hedges, the effective portion of the gain or loss on the derivative is reported as a component of other comprehensive (loss) income and is reclassified into earnings in the same period or periods during which the hedged transaction affects earnings. Gains and losses on the derivative instruments representing either hedge ineffectiveness or hedge components excluded from the assessment of effectiveness are recognized in current earnings. The amount of hedge ineffectiveness charged to profit and loss is not material for any period presented.

For those commodity swaps which are not designated as cash flow hedges, the fair value of the commodity swap is recognized as an asset or liability in the consolidated balance sheet and the related gain or loss on the derivative is reported in current earnings.

As of December 31, 2016 and December 31, 2015, the Company had outstanding copper swap contracts of the following amounts:

	Units Outstanding (in Pounds)		Net Fair Value - Asset (Liability)
	December 31, 2016	December 31, 2015	December 31, 2016		December 31, 2015
(Amounts in millions)
Cash flow hedges	42.6	17.3	$	10.6	$	(9.8	)
Not designated as hedges	6.5	4.0		1.0		(0.7	)
Total	49.1	21.3	$	11.6	$	(10.5	)

As of December 31, 2016 and December 31, 2015, the fair value of the outstanding copper swap contracts is recorded in the balance sheet as follows:

	December 31, 2016			December 31, 2015
(Dollars in millions)
Other current assets	$	12.5		$	0.1
Accrued liabilities		(0.9	)		(10.6	)
Net asset (liability) on balance sheet	$	11.6		$	(10.5	)
Accumulated other comprehensive gain (loss), net of tax	$	6.9		$	(6.1	)

In the next twelve months the Company estimates that $4.1 million of unrealized gains, net of tax, related to commodity price hedging will be reclassified from other comprehensive income (loss) into earnings.

See the Consolidated Statement of Comprehensive Income and Consolidated Statement of Shareholders’ Equity for amounts recorded in other comprehensive income and for amounts reclassified from accumulated other comprehensive income into net income for the periods specified below. For the twelve months ended December 31, 2016 and 2015, the following amounts were recognized in earnings related to copper swap contracts:

	Twelve Months Ended December 31,
	2016			2015
(Dollars in millions)
Gain (loss) from ineffectiveness of cash flow hedges	$	(0.4	)	$	(0.1	)
Gain (loss) from contracts not designated as hedges		1.7			(0.7	)
Net	$	1.3		$	(0.8	)

Forward contracts related to foreign currency are not designated as hedges and fair value changes in these contracts are immediately charged to earnings and are classified in cost of sales in the Condensed Consolidated Statement of Operations and Comprehensive Income (Loss). As of December 31, 2016, the Company has outstanding foreign currency forward contracts with a net fair value totaling $1.0 million, consisting of a gross derivative liability of $0.9 million (recognized in accrued liabilities in the balance sheet) and a gross derivative asset of $1.9 million (recognized in other current assets in the balance sheet.) As of December 31, 2015, the Company has outstanding currency forward contracts with a net fair value totaling $(1.9) million, recognized as a liability in accrued liabilities in the Consolidated Balance Sheet.

As of December 31, 2016 and December 31 2015, the net currency units outstanding were:

	December 31, 2016		December 31, 2015
(In millions)
British Pounds		GBP 7.3		GBP 5.9
New Zealand Dollars		NZD 15.5		NZD 22.5
United States Dollars		USD 24.7		USD 40.0
Canadian Dollars		CAD 0.3		CAD 0.0

- Definition

The entire disclosure for derivative instruments and hedging activities including, but not limited to, risk management strategies, non-hedging derivative instruments, assets, liabilities, revenue and expenses, and methodologies and assumptions used in determining the amounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6441202&loc=d3e80720-113993

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64837297&loc=d3e41620-113959

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624163-113959

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5579240-113959

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4D
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624177-113959

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80784-113994

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=64837297&loc=d3e41641-113959

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5579245-113959

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4H
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624258-113959

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4K
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5708775-113959

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4J
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5708773-113959

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5618551-113959

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5580258-113959

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4E
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624181-113959

Reference 17: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

Reference 18: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=64837297&loc=d3e41638-113959

Reference 19: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(n))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Common Stock and Senior Convertible Preferred Stock

12 Months Ended

Dec. 31, 2016

Text Block [Abstract]

Common Stock And Senior Convertible Preferred Stock

19. Common Stock and Senior Convertible Preferred Stock

Changes in senior convertible preferred stock, common stock and treasury stock for the three years ended December 31, 2016 are as follows:

	Year Ended December 31,
	2016			2015			2014
(Shares in thousands)
Senior Convertible Preferred Stock:
Balance at beginning and end of year		0			0			0
Common Stock:
Balance at beginning of year		22,016			21,938			21,722
Issued for employee stock plans		125			78			216
Balance at end of year		22,141			22,016			21,938
Treasury Stock:
Balance at beginning of year		(1,459	)		(1,443	)		(1,390	)
Shares repurchased		(17	)		(16	)		(53	)
Balance at end of year		(1,476	)		(1,459	)		(1,443	)

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 4.E)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(e))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(31))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(30))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(d))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

+ Details

Commitments and Contingent Liabilities

12 Months Ended

Dec. 31, 2016

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingent Liabilities

20. Commitments and Contingent Liabilities

The Company and its subsidiaries are involved in litigation and various proceedings relating to environmental laws and regulations and toxic tort, product liability and other matters. Certain of these matters are discussed below. The ultimate resolution of these contingencies is subject to significant uncertainty and should the Company or its subsidiaries fail to prevail in any of these legal matters or should several of these legal matters be resolved against the Company or its subsidiaries in the same reporting period, these legal matters could, individually or in the aggregate, be material to the consolidated financial statements.

Legal Proceedings

Coal Tar Pitch Cases. Koppers Inc. is one of several defendants in lawsuits filed in two states in which the plaintiffs claim they suffered a variety of illnesses (including cancer) as a result of exposure to coal tar pitch sold by the defendants. There were 99 plaintiffs in 55 cases pending as of December 31, 2016 as compared to 110 plaintiffs in 59 cases pending as of December 31, 2015. As of December 31, 2016, there are a total of 54 cases pending in state court in Pennsylvania, and one case pending in state court in Tennessee.

The plaintiffs in all 55 pending cases seek to recover compensatory damages. Plaintiffs in 50 of those cases also seek to recover punitive damages. The plaintiffs in the 54 cases filed in Pennsylvania state court seek unspecified damages in excess of the court’s minimum jurisdictional limit. The plaintiff in the Tennessee state court case seeks damages of $15.0 million. The other defendants in these lawsuits vary from case to case and include companies such as Beazer East, Inc. (“Beazer East”), Honeywell International Inc., Graftech International Holdings, Dow Chemical Company, UCAR Carbon Company, Inc., and SGL Carbon Corporation. Discovery is proceeding in these cases. No trial dates have been set in any of these cases.

The Company has not provided a reserve for these lawsuits because, at this time, the Company cannot reasonably determine the probability of a loss, and the amount of loss, if any, cannot be reasonably estimated. The timing of resolution of these cases cannot be reasonably determined. Although Koppers Inc. is vigorously defending these cases, an unfavorable resolution of these matters may have a material adverse effect on the Company’s business, financial condition, cash flows and results of operations.

Gainesville. Koppers Inc. operated a utility pole treatment plant in Gainesville from December 29, 1988 until its closure in 2009. The property upon which the utility pole treatment plant was located was sold by Koppers Inc. to Beazer East in 2010.

In November 2010, a class action complaint was filed in the Circuit Court of the Eighth Judicial Circuit located in Alachua County, Florida by residential real property owners located in a neighborhood west of and immediately adjacent to the former utility pole treatment plant in Gainesville. The complaint named Koppers Holdings Inc., Koppers Inc., Beazer East and several other parties as defendants. In a second amended complaint, plaintiffs allege that chemicals and contaminants from the Gainesville plant have contaminated real properties, have caused property damage (diminution in value) and have placed residents and owners of the putative class properties at an elevated risk of exposure to and injury from the chemicals at issue. The plaintiffs presently seek a class comprised of all current property owners of single family residential properties with a polygon-shaped area extending approximately two miles from the former plant area (which area encompasses approximately 7,000 owners).

This case was removed to the United States District court for the Northern District of Florida in December 2010. Koppers Holdings Inc. was dismissed from the case by the district court for lack of personal jurisdiction. Class factual discovery closed in May 2015 and expert witness discovery was completed in August 2015. Discovery on the merits is stayed until further order of the court. Motions were subsequently filed by each side to strike or limit the testimony of the other side’s experts. Plaintiffs filed a motion for class certification on September 30, 2015 and the response of Koppers Inc. was filed on October 30, 2015. A hearing on plaintiffs’ motions for class certification and the parties’ motions relating to experts was held in January 2016 and the parties await a ruling from the court.

The Company has not provided a reserve for this matter because, at this time, it cannot reasonably determine the probability of a loss, and the amount of loss, if any, cannot be reasonably estimated. The timing of resolution of this case cannot be reasonably determined. Although the Company is vigorously defending this case, an unfavorable resolution of this matter may have a material adverse effect on the Company’s business, financial condition, cash flows and results of operations.

Environmental and Other Litigation Matters

The Company and its subsidiaries are subject to federal, state, local and foreign laws and regulations and potential liabilities relating to the protection of the environment and human health and safety including, among other things, the cleanup of contaminated sites, the treatment, storage and disposal of wastes, the discharge of effluent into waterways, the emission of substances into the air and various health and safety matters. The Company’s subsidiaries expect to incur substantial costs for ongoing compliance with such laws and regulations. The Company’s subsidiaries may also face governmental or third-party claims, or otherwise incur costs, relating to cleanup of, or for injuries resulting from, contamination at sites associated with past and present operations. The Company accrues for environmental liabilities when a determination can be made that a liability is probable and reasonably estimable.

Environmental and Other Liabilities Retained or Assumed by Others. The Company’s subsidiaries have agreements with former owners of certain of their operating locations under which the former owners retained, assumed and/or agreed to indemnify such subsidiaries against certain environmental and other liabilities. The most significant of these agreements was entered into at Koppers Inc.’s formation on December 29, 1988 (the “Acquisition”). Under the related asset purchase agreement between Koppers Inc. and Beazer East, subject to certain limitations, Beazer East retained the responsibility for and agreed to indemnify Koppers Inc. against certain liabilities, damages, losses and costs, including, with certain limited exceptions, liabilities under and costs to comply with environmental laws to the extent attributable to acts or omissions occurring prior to the Acquisition and liabilities related to products sold by Beazer East prior to the Acquisition (the “Indemnity”). Beazer Limited, the parent company of Beazer East, unconditionally guaranteed Beazer East’s performance of the Indemnity pursuant to a guarantee (the “Guarantee”).

The Indemnity provides different mechanisms, subject to certain limitations, by which Beazer East is obligated to indemnify Koppers Inc. with regard to certain environmental, product and other liabilities and imposes certain conditions on Koppers Inc. before receiving such indemnification, including, in some cases, certain limitations regarding the time period as to which claims for indemnification can be brought. In July 2004, Koppers Inc. and Beazer East agreed to amend the environmental indemnification provisions of the December 29, 1988 asset purchase agreement to extend the indemnification period for pre-closing environmental liabilities through July 2019. As consideration for the amendment, Koppers Inc. paid Beazer East a total of $7.0 million and agreed to share toxic tort litigation defense costs arising from any sites acquired from Beazer East. The July 2004 amendment did not change the provisions of the Indemnity with respect to indemnification for non-environmental claims, such as product liability claims, which claims may continue to be asserted after July 2019.

Qualified expenditures under the Indemnity are not subject to a monetary limit. Qualified expenditures under the Indemnity include (i) environmental cleanup liabilities required by third parties, such as investigation, remediation and closure costs, relating to pre-December 29, 1988 (“Pre-Closing”) acts or omissions of Beazer East or its predecessors; (ii) environmental claims by third parties for personal injuries, property damages and natural resources damages relating to Pre-Closing acts or omissions of Beazer East or its predecessors; (iii) punitive damages for the acts or omissions of Beazer East and its predecessors without regard to the date of the alleged conduct and (iv) product liability claims for products sold by Beazer East or its predecessors without regard to the date of the alleged conduct. If the third party claims described in sections (i) and (ii) above are not made by July 2019, Beazer East will not be required to pay the costs arising from such claims under the Indemnity. However, with respect to any such claims which are made by July 2019, Beazer East will continue to be responsible for such claims under the Indemnity beyond July 2019. The Indemnity provides for the resolution of issues between Koppers Inc. and Beazer East by an arbitrator on an expedited basis upon the request of either party. The arbitrator could be asked, among other things, to make a determination regarding the allocation of environmental responsibilities between Koppers Inc. and Beazer East. Arbitration decisions under the Indemnity are final and binding on the parties.

Contamination has been identified at most manufacturing and other sites of the Company’s subsidiaries. One site currently owned and operated by Koppers Inc. in the United States is listed on the National Priorities List promulgated under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, as amended (“CERCLA”). Currently, at the properties acquired from Beazer East (which includes the National Priorities List site and all but one of the sites permitted under the Resource Conservation and Recovery Act (“RCRA”)), a significant portion of all investigative, cleanup and closure activities are being conducted and paid for by Beazer East pursuant to the terms of the Indemnity. In addition, other of Koppers Inc.’s sites are or have been operated under RCRA and various other environmental permits, and remedial and closure activities are being conducted at some of these sites.

To date, the parties that retained, assumed and/or agreed to indemnify the Company against the liabilities referred to above, including Beazer East, have performed their obligations in all material respects. The Company believes that, for the last three years ended December 31, 2016, amounts paid by Beazer East as a result of its environmental remediation obligations under the Indemnity have averaged, in total, approximately $10 million per year. Periodically, issues have arisen between Koppers Inc. and Beazer East and/or other indemnitors that have been resolved without arbitration. Koppers Inc. and Beazer East engage in discussions from time to time that involve, among other things, the allocation of environmental costs related to certain operating and closed facilities.

If for any reason (including disputed coverage or financial incapability) one or more of such parties fail to perform their obligations and the Company or its subsidiaries are held liable for or otherwise required to pay all or part of such liabilities without reimbursement, the imposition of such liabilities on the Company or its subsidiaries could have a material adverse effect on its business, financial condition, cash flows and results of operations. Furthermore, the Company could be required to record a contingent liability on its balance sheet with respect to such matters, which could result in a negative impact to the Company’s business, financial condition, cash flows and results of operations.

Domestic Environmental Matters. Koppers Inc. has been named as one of the potentially responsible parties (“PRPs”) at the Portland Harbor CERCLA site located on the Willamette River in Oregon. Koppers Inc. operated a coal tar pitch terminal near the site. Koppers Inc. has responded to an Environmental Protection Agency (“EPA”) information request and has executed a PRP agreement which outlines the process to develop an allocation of past and future costs among more than 80 parties to the site. Koppers Inc. believes it is a de minimus contributor at the site. Additionally, a separate natural resources damages assessment (“NRDA”) is being conducted by a local trustee group. The NRDA is intended to identify further information necessary to estimate liabilities for settlements of national resource damages (“NRD”) claims. Koppers Inc. may also incur liabilities under the NRD process and has entered into a separate process to develop an allocation of NRDA costs. In January 2017, Koppers Inc. was served in an additional NRD action by a separate party and the Company is currently evaluating this new lawsuit.

The EPA issued its Record of Decision (“ROD”) in January 2017 for the Portland Harbor CERCLA site. The selected remedy includes a combination of sediment removal, capping, enhanced and monitored natural recovery and riverbank improvements. The ROD does not determine who is responsible for remediation costs. The net present value and undiscounted costs of the selected remedy as estimated in the ROD are approximately $1.1 billion and $1.7 billion, respectively. Responsibility for implementing and funding that work will be decided in the separate allocation process.

In September 2009, Koppers Inc. received a general notice letter notifying it that it may be a PRP at the Newark Bay CERCLA site. In January 2010, Koppers Inc. submitted a response to the general notice letter asserting that Koppers Inc. is a de minimus party at this site.

The Company has accrued the estimated costs of participating in the PRP group at the Portland Harbor and Newark Bay CERCLA sites and estimated de minimis settlement amounts at the sites totaling $2.0 million at December 31, 2016. The actual cost could be materially higher as there has not been a determination of how those costs will be allocated among the PRPs at the sites. Accordingly, an unfavorable resolution of these matters may have a material adverse effect on the Company’s business, financial condition, cash flows and results of operations.

In connection with Koppers Inc.’s acquisition of certain entities from Osmose, there are two plant sites in the United States where the Company has recorded an environmental remediation liability for soil and groundwater contamination which occurred prior to the acquisition. As of December 31, 2016, the Company’s estimated environmental remediation liability for these acquired sites totals $4.9 million.

Foreign Environmental Matters. In connection with Koppers Inc.’s acquisition of certain entities from Osmose, there are three plant sites located in the United Kingdom and Australia where the Company has recorded an environmental remediation liability for soil and groundwater contamination which occurred prior to the acquisition. As of December 31, 2016, the Company’s estimated environmental remediation liability for these acquired sites totals $3.5 million. Osmose Holdings, Inc. has provided an indemnity of up to $5.0 million for certain environmental response costs incurred prior to August 15, 2017 (the “Osmose Indemnity”). In June 2016, the Company recorded an increase in the receivable under the Osmose Indemnity of $2.9 million related to expected indemnity recoveries associated with the acquired United Kingdom sites. As of December 31, 2016, the receivable with respect to the Osmose Indemnity totaled $1.9 million.

In December 2011, the Company ceased manufacturing operations at its Continental Carbon facility located in Kurnell, Australia. The Company has accrued its expected cost of site remediation resulting from the closure of $1.5 million as of December 31, 2016.

Environmental Reserves Rollforward. The following table reflects changes in the accrued liability for environmental matters, of which $5.2 million and $7.0 million are classified as current liabilities at December 31, 2016 and 2015, respectively:

	Year ended
	December 31, 2016			December 31, 2015
(Dollars in millions)
Balance at beginning of year	$	19.8		$	7.8
Expense		1.5			1.2
Reversal of reserves		(1.0	)		(0.5	)
Cash expenditures		(6.3	)		(1.4	)
Acquisition of Osmose Entities		0.0			13.7
Divestitures		(0.3	)		0.0
Currency translation		(0.8	)		(1.0	)
Balance at end of period	$	12.9		$	19.8

Selected Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2016

Quarterly Financial Information Disclosure [Abstract]

Selected Quarterly Financial Data (Unaudited)

21. Selected Quarterly Financial Data (Unaudited)

The following is a summary of the quarterly results of operations for the years ended December 31, 2016 and 2015:

	Year Ended December 31, 2016
	1^stQuarter			2^nd Quarter		3^rd Quarter		4^th Quarter		Fiscal Year
(Dollars in millions, except per share amounts)
Statement of operations data:
Net sales	$	346.8		$	385.1	$	371.1	$	313.2	$	1,416.2
Operating profit		7.8			32.0		27.7		18.9		86.4
Income (loss) from continuing operations		(2.4	)		11.3		12.0		6.2		27.1
Net income (loss)		(1.8	)		11.3		11.9		6.3		27.7
Net income (loss) attributable to Koppers		(1.3	)		12.1		12.1		6.4		29.3
Common stock data:
Earnings (loss) per common share attributable to Koppers common shareholders: ^(b)
Basic –
Continuing operations	$	(0.09	)	$	0.58	$	0.59	$	0.31	$	1.39
Discontinued operations		0.03			0.00		0.00		0.00		0.03
Earnings (loss) per basic common share	$	(0.06	)	$	0.58	$	0.59	$	0.31	$	1.42
Diluted –
Continuing operations	$	(0.09	)	$	0.57	$	0.58	$	0.30	$	1.36
Discontinued operations		0.03			0.00		0.00		0.00		0.03
Earnings (loss) per diluted common share	$	(0.06	)	$	0.57	$	0.58	$	0.30	$	1.39
Price range of common stock:
High	$	23.43		$	31.35	$	33.71	$	42.70	$	42.70
Low		13.58			21.38		28.54		31.28		13.58

	Year Ended December 31, 2015
	1^stQuarter			2^nd Quarter		3^rd Quarter			4^th Quarter			Fiscal Year
(Dollars in millions, except per share amounts)
Statement of operations data:
Net sales	$	397.8		$	431.6	$	433.8		$	363.7		$	1,626.90
Operating (loss) profit^(a)		8.0			26.0		27.0			(90.6	)		(29.6	)
(Loss) income from continuing operations		(4.2	)		7.9		9.2			(88.8	)		(75.9	)
Net (loss) income		(4.2	)		7.9		9.1			(88.8	)		(76.0	)
Net (loss) income attributable to Koppers		(3.4	)		9.0		10.1			(87.7	)		(72.0	)
Common stock data:
(Loss) earnings per common share attributable to Koppers common shareholders: ^(b)
Basic –
Continuing operations	$	(0.16	)	$	0.44	$	0.49		$	(4.27	)	$	(3.50	)
Discontinued operations		0.00			0.00		(0.01	)		0.00			(0.01	)
(Loss) earnings per basic common share	$	(0.16	)	$	0.44	$	0.48		$	(4.27	)	$	(3.51	)
Diluted –
Continuing operations	$	(0.16	)	$	0.44	$	0.49		$	(4.27	)	$	(3.50	)
Discontinued operations		0.00			0.00		(0.01	)		0.00			(0.01	)
(Loss) earnings per diluted common share	$	(0.16	)	$	0.44	$	0.48		$	(4.27	)	$	(3.51	)
Price range of common stock:
High	$	26.44		$	27.40	$	24.86		$	23.63		$	27.40
Low		15.78			19.26		17.88			17.34			15.78

(a)

In the fourth quarter of 2015, the Company recorded asset impairment, asset retirement and severance charges totaling $35.1 million primarily related to the decision to discontinue coal tar distillation activities at CMC plants located in the United Kingdom and the United States. In the fourth quarter of 2015, the Company also recorded goodwill impairment charges of $67.2 million related to our CMC business.

(b) The cumulative sum of quarterly basic and diluted net income per share amounts may not equal total basic and diluted net income per share amounts for the year due to differences in weighted average and equivalent shares outstanding for each of the periods presented.

Subsidiary Guarantor Information for Koppers Inc. 2025 Notes and Shelf Registration

12 Months Ended

Dec. 31, 2016

Debt Disclosure [Abstract]

Subsidiary Guarantor Information for Koppers Inc. 2025 Notes and Shelf Registration

22. Subsidiary Guarantor Information for Koppers Inc. 2025 Notes and Shelf Registration

2025 Notes

On January 25, 2017, Koppers Inc. issued $500.0 million principal value of Senior Notes due 2025 (the “2025 Notes”). Koppers Holdings and each of Koppers Inc.’s 100 percent-owned material domestic subsidiaries other than Koppers Assurance, Inc. fully and unconditionally guarantee the payment of principal and interest on the 2025 Notes. The domestic guarantor subsidiaries include Koppers World-Wide Ventures Corporation, Koppers Delaware, Inc., Koppers Concrete Products, Inc., Concrete Partners, Inc., Koppers Performance Chemicals Inc., Koppers Railroad Structures Inc., Koppers NZ, LLC, Koppers-Nevada Limited Liability Company, Wood Protection LP, Wood Protection Management LLC and Koppers Asia LLC. Non-guarantor subsidiaries are owned directly or indirectly by Koppers Inc. or are owned directly or indirectly by Koppers World-Wide Ventures Corporation.

The guarantee of a guarantor subsidiary will be automatically and unconditionally released and discharged in the event of:

any sale of the capital stock or substantially all of the assets of the guarantor subsidiary;

the designation of the guarantor subsidiary as an unrestricted subsidiary in accordance with the indenture governing the 2025 Notes; and

the legal defeasance, covenant defeasance or satisfaction and discharge of the indenture governing the 2025 Notes.

Shelf Registration

Under a registration statement on Form S-3, Koppers Holdings may sell a combination of securities, including common stock, debt securities, preferred stock, depository shares, warrants, purchase contracts and units, from time to time in one or more offerings. In addition, Koppers Inc. may sell debt securities from time to time under the registration statement. Debt securities may be fully and unconditionally guaranteed, on a joint and several basis, by Koppers Holdings, Koppers Inc. and/or each of Koppers Inc.’s 100 percent-owned material domestic subsidiaries other than Koppers Assurance, Inc. The domestic guarantor subsidiaries are the same as those which guarantee the 2025 Notes. Non-guarantor subsidiaries are owned directly or indirectly by Koppers Inc. or are owned directly or indirectly by Koppers World-Wide Ventures Corporation. The guarantor subsidiaries that issue guarantees, if any, will be determined when a debt offering actually occurs under the registration statement and accordingly, the condensed consolidating financial information for subsidiary guarantors will be revised to identify the subsidiaries that actually provided guarantees. These guarantees will be governed pursuant to a supplement indenture which the trustee and the issuing company would enter into concurrent with the debt offering.

Reliance of Koppers Holdings on Earnings of Koppers Inc. and its Subsidiaries

Koppers Holdings depends on the dividends from the earnings of Koppers Inc. and its subsidiaries to generate the funds necessary to meet its financial obligations, including the payment of any declared dividend of Koppers Holdings. As with the Prior Senior Secured Credit Facilities, the New Senior Secured Credit Facility prohibits Koppers Inc. from making dividend payments to Koppers Holdings unless (1) such dividend payments are permitted by the indenture governing Koppers Inc.’s 2025 Notes, (2) no event of default or potential default has occurred or is continuing under the credit agreement, and (3) we are in pro forma compliance with our fixed charge coverage ratio covenant after giving effect to such dividend. The indenture governing the 2025 Notes restrict Koppers Inc.’s ability to finance our payment of dividends if (1) a default has occurred or would result from such financing, (2) Koppers Inc., or a restricted subsidiary of Koppers Inc. which is not a guarantor under the applicable indenture is not able to incur additional indebtedness (as defined in the applicable indenture), and (3) the sum of all restricted payments (as defined in the applicable indenture) have exceeded the permitted amount (which we refer to as the “basket”) at such point in time.

The Koppers Inc. New Senior Secured Credit Facility agreement provides for a revolving credit facility of up to $400.0 million at variable rates. Borrowings under the revolving credit facility are secured by a first priority lien on substantially all of the assets of Koppers Inc. and its material domestic subsidiaries. The revolving credit facility agreement contains certain covenants for Koppers Inc. and its restricted subsidiaries that limit capital expenditures, additional indebtedness, liens, dividends, investments or acquisitions. In addition, such covenants give rise to events of default upon the failure by Koppers Inc. and its restricted subsidiaries to meet certain financial ratios.

As of December 31, 2016, Koppers Inc.’s assets exceeded its liabilities by $29.8 million. There are no net assets unavailable for distribution to Koppers Holdings Inc. by Koppers Inc. as of December 31, 2016. Cash dividends paid to Koppers Holdings Inc. by its subsidiaries totaled $1.2 million, $6.5 million and $23.6 million for the years ended December 31, 2016, 2015 and 2014, respectively.

Condensed Consolidating Statement of Comprehensive Income (Loss)

For the Year Ended December 31, 2016

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries		Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Net sales	$	0.0		$	660.7		$	350.6	$	504.7		$	(99.8	)	$	1,416.2
Cost of sales including depreciation and amortization		0.0			637.4			252.3		412.4			(101.2	)		1,200.9
Gain on sale of business		0.0			0.0			0.0		(2.1	)		0.0			(2.1	)
Selling, general and administrative		1.9			47.7			38.2		43.2			0.0			131.0
Operating (loss) profit		(1.9	)		(24.4	)		60.1		51.2			1.4			86.4
Other income (loss)		0.0			0.3			4.1		0.3			(1.8	)		2.9
Equity income of subsidiaries		30.6			79.1			35.9		0.0			(145.6	)		0.0
Interest (income) expense		0.0			47.6			0.0		5.0			(1.8	)		50.8
Income taxes		(0.6	)		(23.2	)		22.2		13.0			0.0			11.4
Income from continuing operations		29.3			30.6			77.9		33.5			(144.2	)		27.1
Discontinued operations		0.0			0.0			0.0		0.6			0.0			0.6
Noncontrolling interests		0.0			0.0			0.0		(1.6	)		0.0			(1.6	)
Net income attributable to Koppers	$	29.3		$	30.6		$	77.9	$	35.7		$	(144.2	)	$	29.3
Comprehensive income (loss) attributable to Koppers	$	40.5		$	41.3		$	85.0	$	29.6		$	(155.9	)	$	40.5

Condensed Consolidating Statement of Comprehensive (Loss) Income

For the Year Ended December 31, 2015

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Net sales	$	0.0		$	791.1		$	335.6		$	600.9		$	(100.7	)	$	1,626.9
Cost of sales including depreciation and amortization		0.0			771.7			233.2			562.4			(99.4	)		1,467.9
Gain on sale of business		0.0			(3.2	)		0.0			0.0			0.0			(3.2	)
Goodwill impairment		0.0			43.1			24.1			0.0			0.0			67.2
Selling, general and administrative		1.9			41.3			37.8			43.6			0.0			124.6
Operating (loss) profit		(1.9	)		(61.8	)		40.5			(5.1	)		(1.3	)		(29.6	)
Other income (loss)		0.0			0.5			4.1			(2.4	)		(2.0	)		0.2
Equity income of subsidiaries		(70.8	)		0.9			(27.9	)		0.0			97.8			0.0
Interest expense		0.0			45.8			0.0			6.9			(2.0	)		50.7
Income taxes		(0.7	)		(35.4	)		15.8			16.4			(0.3	)		(4.2	)
(Loss) income from continuing operations		(72.0	)		(70.8	)		0.9			(30.8	)		96.8			(75.9	)
Discontinued operations		0.0			0.0			0.0			(0.1	)		0.0			(0.1	)
Noncontrolling interests		0.0			0.0			0.0			(4.0	)		0.0			(4.0	)
Net income attributable to Koppers	$	(72.0	)	$	(70.8	)	$	0.9		$	(26.9	)	$	96.8		$	(72.0	)
Comprehensive income (loss) attributable to Koppers	$	(91.5	)	$	(90.3	)	$	(18.1	)	$	(41.8	)	$	150.2		$	(91.5	)

Condensed Consolidating Statement of Comprehensive (Loss) Income

For the Year Ended December 31, 2014

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Net sales	$	0.0		$	795.9		$	143.0		$	683.5		$	(67.4	)	$	1,555.0
Cost of sales including depreciation and amortization		0.0			724.5			108.8			639.0			(66.7	)		1,405.6
Selling, general and administrative		2.2			59.2			17.4			37.4			0.0			116.2
Operating (loss) profit		(2.2	)		12.2			16.8			7.1			(0.7	)		33.2
Other income (loss)		0.0			0.2			4.7			(0.6	)		(4.3	)		0.0
Equity income of subsidiaries		(31.0	)		(15.9	)		(6.4	)		0.0			53.3			0.0
Interest expense		0.0			36.5			0.0			6.9			(4.3	)		39.1
Income taxes		(0.8	)		(9.0	)		30.5			13.4			0.0			34.1
Income from continuing operations		(32.4	)		(31.0	)		(15.4	)		(13.8	)		52.6			(40.0	)
Discontinued operations		0.0			0.0			(0.6	)		1.2			0.0			0.6
Noncontrolling interests		0.0			0.0			0.0			(7.0	)		0.0			(7.0	)
Net income attributable to Koppers	$	(32.4	)	$	(31.0	)	$	(16.0	)	$	(5.6	)	$	52.6		$	(32.4	)
Comprehensive income (loss) attributable to Koppers	$	(82.5	)	$	(81.1	)	$	(54.4	)	$	(35.1	)	$	170.6		$	(82.5	)

Condensed Consolidating Balance Sheet

December 31, 2016

	Parent		Koppers Inc.		Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries		Consolidating Adjustments			Consolidated
(Dollars in millions)
ASSETS
Cash and cash equivalents	$	0.0	$	0.0	$	0.0		$	20.8	$	0.0		$	20.8
Receivables, net		0.0		50.8		25.4			64.4		0.0			140.6
Affiliated receivables		0.7		34.8		32.2			15.4		(83.1	)		0.0
Inventories, net		0.0		106.6		23.9			99.0		(0.8	)		228.7
Other current assets		0.0		5.1		13.4			29.2		0.3			48.0
Total current assets		0.7		197.3		94.9			228.8		(83.6	)		438.1
Equity investments		29.9		697.4		195.4			0.0		(922.7	)		0.0
Property, plant and equipment, net		0.0		126.7		39.6			114.5		0.0			280.8
Goodwill		0.0		0.8		153.1			32.5		0.0			186.4
Intangible assets, net		0.0		7.9		107.1			26.9		0.0			141.9
Deferred tax assets		0.0		29.7		(8.4	)		5.8		0.0			27.1
Affiliated loan receivables		0.0		36.9		205.3			21.9		(264.1	)		0.0
Other assets		0.0		5.5		6.1			1.6		0.0			13.2
Total assets	$	30.6	$	1,102.2	$	793.1		$	432.0	$	(1,270.4	)	$	1,087.5
LIABILITIES AND EQUITY
Accounts payable	$	0.2	$	69.6	$	38.9		$	35.5	$	0.0		$	144.2
Affiliated payables		0.0		46.0		20.7			24.5		(91.2	)		0.0
Accrued liabilities		0.0		49.5		18.9			37.9		0.0			106.3
Current maturities of long-term debt		0.0		30.2		0.0			12.4		0.0			42.6
Total current liabilities		0.2		195.3		78.5			110.3		(91.2	)		293.1
Long-term debt		0.0		592.0		0.0			27.8		0.0			619.8
Affiliated debt		0.0		209.9		23.5			30.7		(264.1	)		0.0
Other long-term liabilities		0.0		75.0		11.6			53.4		0.0			140.0
Total liabilities		0.2		1,072.2		113.6			222.2		(355.3	)		1,052.9
Koppers shareholders’ equity		30.4		30.0		679.5			205.6		(915.1	)		30.4
Noncontrolling interests		0.0		0.0		0.0			4.2		0.0			4.2
Total liabilities and equity	$	30.6	$	1,102.2	$	793.1		$	432.0	$	(1,270.4	)	$	1,087.5

Condensed Consolidating Balance Sheet

December 31, 2015

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries		Non-Guarantor Subsidiaries		Consolidating Adjustments			Consolidated
(Dollars in millions)
ASSETS
Cash and cash equivalents	$	0.0		$	0.1		$	0.7	$	21.0	$	0.0		$	21.8
Receivables, net		0.0			60.4			23.7		75.5		0.0			159.6
Affiliated receivables		0.0			14.3			15.2		4.4		(33.9	)		0.0
Inventories, net		0.0			111.9			24.9		91.8		(2.2	)		226.4
Deferred tax assets		0.0			0.0			0.0		0.0		0.0			0.0
Other current assets		0.0			3.7			1.9		30.9		0.0			36.5
Total current assets		0.0			190.4			66.4		223.6		(36.1	)		444.3
Equity investments		(19.0	)		703.2			165.7		0.0		(849.9	)		0.0
Property, plant and equipment, net		0.0			117.5			41.2		119.1		0.0			277.8
Goodwill		0.0			0.8			153.1		32.7		0.0			186.6
Intangible assets, net		0.0			8.7			117.6		29.8		0.0			156.1
Deferred tax assets		0.0			29.8			0.8		5.7		0.3			36.6
Affiliated loan receivables		0.7			29.6			222.6		31.7		(284.6	)		0.0
Other assets		(0.2	)		4.5			4.9		2.3		0.0			11.5
Total assets	$	(18.5	)	$	1,084.5		$	772.3	$	444.9	$	(1,170.3	)	$	1,112.9
LIABILITIES AND EQUITY
Accounts payable	$	0.0		$	73.8		$	18.9	$	48.1	$	0.0		$	140.8
Affiliated payables		0.0			16.6			10.9		15.3		(42.8	)		0.0
Accrued liabilities		0.0			35.6			23.4		40.8		0.0			99.8
Current maturities of long-term debt		0.0			30.2			0.0		9.7		0.0			39.9
Total current liabilities		0.0			156.2			53.2		113.9		(42.8	)		280.5
Long-term debt		0.0			647.5			0.0		34.9		0.0			682.4
Affiliated debt		0.0			217.5			29.5		36.9		(283.9	)		0.0
Other long-term liabilities		0.0			81.6			13.2		67.6		0.0			162.4
Total liabilities		0.0			1,102.8			95.9		253.3		(326.7	)		1,125.3
Koppers shareholders’ equity		(18.5	)		(18.3	)		676.4		185.5		(843.6	)		(18.5	)
Noncontrolling interests		0.0			0.0			0.0		6.1		0.0			6.1
Total liabilities and equity	$	(18.5	)	$	1,084.5		$	772.3	$	444.9	$	(1,170.3	)	$	1,112.9

Condensed Consolidating Statement of Cash Flows

For the Year Ended December 31, 2016

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Cash provided by (used in) operating activities	$	(0.1	)	$	106.6		$	77.0		$	29.1		$	(93.1	)	$	119.5
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions		0.0			(30.1	)		(7.1	)		(12.7	)		0.0			(49.9	)
Repayments (loans to) from affiliates		0.0			(6.9	)		16.9			9.8			(19.8	)		0.0
Net cash proceeds (payments) from divestitures and asset sales		0.0			00.0			0.9			(4.7	)		00.0			(3.8	)
Net cash (used in) provided by investing activities		0.0			(37.0	)		10.7			(7.6	)		(19.8	)		(53.7	)
Cash provided by (used in) financing activities:
(Repayments) borrowings of long-term debt		0.0			(59.9	)		0.1			(1.6	)		0.0			(61.4	)
Borrowings (repayments) of affiliated debt		0.0			(7.2	)		(6.5	)		(6.1	)		19.8			00.0
Deferred financing costs		0.0			(1.4	)		0.0			0.0			0.0			(1.4	)
Dividends paid		(0.0	)		(1.2	)		(82.0	)		(9.9	)		93.1			(0.0	)
Stock repurchased		0.1			0.0			0.0			0.0			0.0			0.1
Net cash used in financing activities		0.1			(69.7	)		(88.4	)		(17.6	)		112.9			(62.7	)
Effect of exchange rates on cash		0.0			0.0			0.0			(4.1	)		0.0			(4.1	)
Net increase (decrease) in cash and cash equivalents		0.0			(0.1	)		(0.7	)		(0.2	)		0.0			(1.0	)
Cash and cash equivalents at beginning of year		0.0			0.1			0.7			21.0			0.0			21.8
Cash and cash equivalents at end of period	$	0.0		$	0.0		$	0.0		$	20.8		$	0.0		$	20.8

Condensed Consolidating Statement of Cash Flows

For the Year Ended December 31, 2015

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Cash provided by (used in) operating activities	$	5.4		$	63.0		$	55.9		$	60.3		$	(56.9	)	$	127.7
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions		0.0			(41.2	)		(5.3	)		(9.5	)		0.0			(56.0	)
(Loans to) repayments from affiliates		0.0			6.3			(5.1	)		9.2			(10.4	)		0.0
Net cash proceeds from divestitures and asset sales		0.0			12.3			2.1			0.5			0.0			14.9
Net cash (used in) provided by investing activities		0.0			(22.6	)		(8.3	)		0.2			(10.4	)		(41.1	)
Cash provided by (used in) financing activities:
Borrowings (repayments) of long-term debt		0.0			(104.2	)		0.1			(9.3	)		0.0			(113.4	)
Borrowings (repayments) of affiliated debt		0.0			71.0			(6.4	)		(75.0	)		10.4			0.0
Deferred financing costs		0.0			(1.0	)		0.0			0.0			0.0			(1.0	)
Dividends paid		(5.1	)		(6.2	)		(40.8	)		(13.5	)		56.9			(8.7	)
Stock (repurchased) issued		(0.3	)		0.0			0.0			0.0			0.0			(0.3	)
Net cash (used in) provided by financing activities		(5.4	)		(40.4	)		(47.1	)		(97.8	)		67.3			(123.4	)
Effect of exchange rates on cash		0.0			0.1			(0.7	)		8.1			0.0			7.5
Net (decrease) increase in cash and cash equivalents		0.0			0.1			(0.2	)		(29.2	)		0.0			(29.3	)
Cash and cash equivalents at beginning of year		0.0			0.0			0.9			50.2			0.0			51.1
Cash and cash equivalents at end of period	$	0.0		$	0.1		$	0.7		$	21.0		$	0.0		$	21.8

Condensed Consolidating Statement of Cash Flows

For the Year Ended December 31, 2014

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Cash provided by (used in) operating activities	$	21.8		$	23.8		$	33.8		$	10.4		$	(54.3	)	$	35.5
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions		0.0			(518.5	)		(16.7	)		(59.9	)		14.8			(580.3	)
(Loans to) repayments from affiliates		0.0			(32.2	)		(38.9	)		0.0			71.1			0.0
Net cash proceeds (payments) from divestitures and asset sales		0.0			0.1			0.1			0.1			0.0			0.3
Net cash used in investing activities		0.0			(550.6	)		(55.5	)		(59.8	)		85.9			(580.0	)
Cash provided by (used in) financing activities:
Repayments of long-term debt		0.0			497.0			0.0			50.5			0.0			547.5
Borrowings of affiliated long- term debt		0.0			35.8			27.6			7.7			(71.1	)		0.0
Deferred financing costs		0.0			(11.1	)		0.0			0.0			0.0			(11.1	)
Other financing receipts		0.0			0.0			0.0			1.4			0.0			1.4
Dividends paid		(20.5	)		(23.6	)		(6.1	)		(24.5	)		54.3			(20.4	)
Stock issued and repurchased		(1.3	)		0.0			0.0			14.8			(14.8	)		(1.3	)
Net cash provided by (used in) financing activities		(21.8	)		498.1			21.5			49.9			(31.6	)		516.1
Effect of exchange rates on cash		0.0			(1.2	)		1.0			(2.5	)		0.0			(2.7	)
Net increase in cash and cash equivalents		0.0			(29.9	)		0.8			(2.0	)		0.0			(31.1	)
Cash and cash equivalents at beginning of year		0.0			29.9			0.1			52.2			0.0			82.2
Cash and cash equivalents at end of period	$	0.0		$	0.0		$	0.9		$	50.2		$	0.0		$	51.1

Schedule II - Valuation and Qualifying Accounts

12 Months Ended

Dec. 31, 2016

Valuation And Qualifying Accounts [Abstract]

Schedule II - Valuation and Qualifying Accounts

SCHEDULE II – VALUATION AND QUALIFYING ACCOUNTS

For the years ended December 31, 2016, 2015 and 2014

								Net
	Balance at				Increase			(Write-						Balance
	Beginning		Business		(Decrease)			Offs)			Currency			at End
	of Year		Acquisition		to Expense			Recoveries			Translation			of Year
(Dollars in millions)
2016
Allowance for doubtful accounts	$	6.5	$	0.0	$	0.7		$	(3.4	)	$	0.0		$	3.8
Inventory obsolescence reserves	$	2.3	$	0.0	$	(0.4	)	$	0.0		$	0.0		$	1.9
Deferred tax valuation allowance	$	41.9	$	0.0	$	0.9		$	(1.5	)	$	(1.1	)	$	40.2
2015
Allowance for doubtful accounts	$	5.6	$	0.0	$	1.3		$	0.0		$	(0.4	)	$	6.5
Inventory obsolescence reserves	$	3.4	$	0.0	$	(1.0	)	$	0.0		$	(0.1	)	$	2.3
Deferred tax valuation allowance	$	32.4	$	0.0	$	10.1		$	0.0		$	(0.6	)	$	41.9
2014
Allowance for doubtful accounts	$	3.6	$	2.6	$	(0.2	)	$	0.0		$	(0.4	)	$	5.6
Inventory obsolescence reserves	$	1.7	$	0.8	$	1.0		$	0.0		$	(0.1	)	$	3.4
Deferred tax valuation allowance	$	19.7	$	1.5	$	11.4		$	0.0		$	(0.2	)	$	32.4

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2016

Accounting Policies [Abstract]

Basis of Presentation

Use of Estimates

Foreign Currency Translation

Revenue Recognition

Research and Development

Cash and Cash Equivalents

Cash and cash equivalents – Cash and cash equivalents include cash on hand and on deposit and investments in highly liquid investments with an original maturity of 90 days or less.

Accounts Receivable

Inventories

Property, Plant and Equipment

Goodwill and Other Intangible Assets

Deferred Income Taxes

Self-insured Liabilities

	2016			2015
(Dollars in millions)
Self-insured liabilities at beginning of year	$	8.0		$	8.2
Expense		5.1			2.6
Reserves recoverable from insurance		2.4			0.0
Reversal of self-insured liabilities		(1.7	)		(1.0	)
Cash expenditures		(2.9	)		(1.8	)
Self-insured liabilities at end of year	$	10.9		$	8.0

Derivative Financial Instruments

Asset Retirement Obligations

The following table describes changes to the Company’s asset retirement obligation liabilities at December 31, 2016 and 2015:

	2016			2015
(Dollars in millions)
Asset retirement obligation at beginning of year	$	46.5		$	30.5
(Divestiture) acquisition		(8.0	)		0.7
Accretion expense		7.1			3.7
Revision in estimated cash flows ^(a)		2.7			24.4
Cash expenditures		(11.4	)		(12.1	)
Currency translation		(0.9	)		(0.7	)
Balance at end of period	$	36.0		$	46.5

Litigation and Contingencies

Other Current Assets

Other current assets – Included in other current assets are prepaid expenses totaling $17.0 million and $17.0 million at December 31, 2016 and 2015, respectively.

Environmental Liabilities

Deferred Revenue from Extended Product Warranty Liabilities

	2016			2015
(Dollars in millions)
Deferred revenue at beginning of year	$	30.1		$	2.5
Advance payment		0.0			30.0
Revenue earned		(0.8	)		(1.0	)
Currency translation		(2.1	)		(1.4	)
Deferred revenue at end of year	$	27.2		$	30.1

Stock-based Compensation

New Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 requires an entity to recognize revenue in a manner that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In March 2016, the FASB issued ASU No. 2016-08, “Principal versus Agent Considerations (Reporting Revenue Gross versus Net),” that amends the principal versus agent guidance in ASU 2014-09. ASU 2016-08 clarifies that the analysis must focus on whether the entity has control of the goods or services before they are transferred to the customer. In April 2016, the FASB issued ASU 2016-10, “Identifying Performance Obligations and Licensing”, which clarifies the implementation guidance in ASU 2014-09 relating to the identification of performance obligations in a contract, including how entities should account for shipping and handling services it provides after control of goods transfers to a customer. In May 2016, the FASB issued ASU 2016-12, “Narrow-Scope Improvements and Practical Expedients”, which clarifies revenue recognition guidance related to the presentation of sales taxes, noncash consideration, and completed contracts and contract modifications. In December 2016, the FASB issued ASU 2016-20, “Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers”, which clarifies the scope and application of the adoption of the new revenue recognition standard.

Collectively, the revenue recognition ASC updates are effective for annual reporting periods beginning after December 15, 2017 with early adoption permitted and allows for the use of either the retrospective or cumulative effect transition method. The Company intends to adopt these standards effective January 1, 2018 but has not yet determined which transition method will be used. The Company has a project team analyzing significant contracts with customers to determine the impact of the adoption of the ASU updates on the Company’s financial statements and disclosures. The Company will continue to assess the impact the ASC updates will have on its revenue arrangements with a final evaluation of the impact of adopting these ASC updates expected to be completed during the third quarter of 2017.

In August 2016, the FASB issued ASU No. 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments.” The update clarifies how entities should classify certain cash receipts and cash payments on the statement of cash flow. The amendments in this update are effective for periods beginning after December 15, 2017. The Company is in the process of assessing the impact the adoption of this ASU will have on its consolidated financial statements.

In March 2016, the FASB issued ASU No. 2016-09, “Improvements to Employee Share-Based Payment Accounting.” This ASU makes several modifications related to the accounting for forfeitures, employer tax withholding on share-based compensation and the financial statement presentation of excess tax benefits or deficiencies. The amendments in this ASU are effective for periods beginning after December 15, 2016. The Company does not expect the adoption of this ASU will have a material impact on its consolidated financial statements.

In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842).” ASU 2016-02 requires an entity to recognize a right-of-use asset and lease liability for all leases with terms of more than one year. Recognition, measurement and presentation of expenses will depend on classification as a finance or operating lease. The standard is effective January 1, 2019 and early adoption is permitted. The guidance requires a modified retrospective adoption. The Company is currently evaluating the impact the adoption of ASU 2016-02 will have on its consolidated financial statements.

In April 2015, the FASB issued ASU No. 2015-03, “Simplifying the Presentation of Debt Issuance Costs,” which requires companies to present debt issuance costs associated with a debt liability as a deduction from the carrying amount of that debt liability on the balance sheet rather than being capitalized as an asset. The standard is effective for interim and annual periods beginning after December 15, 2015, and retrospective presentation is required. The Company adopted this guidance as of January 1, 2016 and the consolidated financial statements have been revised to reflect the retrospective presentation requirement. As a result, $12.5 million and $14.6 million of debt issuance costs have been reclassified from other assets to long-term debt as of December 31, 2015 and December 31, 2014, retrospectively. This reclassification has also been reflected within the notes to the consolidated financial statements as applicable.

In August 2014, the FASB issued ASU No. 2014-15, “Disclosure of Uncertainties About an Entity’s Ability to Continue as a Going Concern”, which requires management to perform interim and annual assessments of an entity’s ability to continue as a going concern within one year of the date the financial statements are issued and provides guidance on determining when and how to disclose going concern uncertainties in the financial statements. The Company adopted this ASU for the year ended December 31, 2016 and the adoption did not have a material effect on the Company’s consolidated financial statements.

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2016

Accounting Policies [Abstract]

Summary of Self-Insured Liabilities

Company’s historical loss experience and projected loss development factors. In 2016 and 2015, reversals of self-insured liabilities occurred as a result of favorable loss trends related to self-insured claims.

	2016			2015
(Dollars in millions)
Self-insured liabilities at beginning of year	$	8.0		$	8.2
Expense		5.1			2.6
Reserves recoverable from insurance		2.4			0.0
Reversal of self-insured liabilities		(1.7	)		(1.0	)
Cash expenditures		(2.9	)		(1.8	)
Self-insured liabilities at end of year	$	10.9		$	8.0

Summary of Asset Retirement Obligation Liabilities

The following table describes changes to the Company’s asset retirement obligation liabilities at December 31, 2016 and 2015:

	2016			2015
(Dollars in millions)
Asset retirement obligation at beginning of year	$	46.5		$	30.5
(Divestiture) acquisition		(8.0	)		0.7
Accretion expense		7.1			3.7
Revision in estimated cash flows ^(a)		2.7			24.4
Cash expenditures		(11.4	)		(12.1	)
Currency translation		(0.9	)		(0.7	)
Balance at end of period	$	36.0		$	46.5

Deferred Revenue from Extended Product Warranty Liabilities

The following table describes changes to the Company’s deferred revenue at December 31, 2016 and 2015:

	2016			2015
(Dollars in millions)
Deferred revenue at beginning of year	$	30.1		$	2.5
Advance payment		0.0			30.0
Revenue earned		(0.8	)		(1.0	)
Currency translation		(2.1	)		(1.4	)
Deferred revenue at end of year	$	27.2		$	30.1

Plant Closures and Discontinued Operations (Tables)

12 Months Ended

Dec. 31, 2016

Discontinued Operations And Disposal Groups [Abstract]

Summary of Restructuring Activities and Related Reserves

Details of the restructuring activities and related reserves are as follows:

	Severance and employee benefits			Environmental remediation			Asset retirement			Other			Total
(Dollars in millions)
Reserve at December 31, 2014	$	0.0		$	4.1		$	3.9		$	0.1		$	8.1
Accrual		2.2			0.6			23.4			1.3			27.5
Costs charged against assets		0.0			0.0			0.0			(1.3	)		(1.3	)
Reversal of accrued charges		0.0			0.0			(0.3	)		0.0			(0.3	)
Cash paid		(0.2	)		0.0			(4.8	)		(0.1	)		(5.1	)
Currency translation		0.0			(0.4	)		(0.3	)		0.0			(0.7	)
Reserve at December 31, 2015	$	2.0		$	4.3		$	21.9		$	0.0		$	28.2
Accrual		2.4			0.1			5.6			5.6			13.7
Costs charged against assets		0.0			0.0			0.0			(1.9	)		(1.9	)
Reversal of accrued charges		(1.9	)		(0.5	)		(8.7	)		(0.1	)		(11.2	)
Cash paid		(1.0	)		(2.4	)		(8.1	)		(0.2	)		(11.7	)
Currency translation		(0.1	)		0.0			(0.7	)		(0.2	)		(1.0	)
Reserve at December 31, 2016	$	1.4		$	1.5		$	10.0		$	3.2		$	16.1

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Schedule of Company's Financial Instruments

Carrying amounts and the related estimated fair values of the Company’s financial instruments as of December 31, 2016 and 2015 are as follows:

	December 31, 2016				December 31, 2015
	Fair Value		Carrying Value		Fair Value		Carrying Value
(Dollars in millions)
Financial assets:
Cash and cash equivalents, including restricted cash	$	20.8	$	20.8	$	21.8	$	21.8
Investments and other assets^(a)		1.1		1.1		1.1		1.1
Financial liabilities:
Long-term debt (including current portion)	$	669.6	$	662.4	$	724.6	$	722.3

(a)	Excludes equity method investments.

Earnings per Common Share (Tables)

12 Months Ended

Dec. 31, 2016

Earnings Per Share [Abstract]

Schedule of Computation of Basic and Diluted Earnings per Common Share

The following table sets forth the computation of basic and diluted earnings per common share:

	Year Ended December 31,
	2016		2015			2014
(Dollars in millions, except share amounts, in thousands, and per share amounts)
Net income (loss) attributable to Koppers	$	29.3	$	(72.0	)	$	(32.4	)
Less: Income (loss) from discontinued operations		0.6		(0.1	)		0.6
Income (loss) from continuing operations attributable to Koppers	$	28.7	$	(71.9	)	$	(33.0	)
Weighted average common shares outstanding:
Basic		20,636		20,541			20,463
Effect of dilutive securities		419		0			0
Diluted		21,055		20,541			20,463
Earnings (loss) per common share – continuing operations:
Basic earnings (loss) per common share	$	1.39	$	(3.50	)	$	(1.61	)
Diluted earnings (loss) per common share		1.36		(3.50	)		(1.61	)
Other data:
Antidilutive securities excluded from computation of diluted earnings per common share		415		688			362

Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

Stock Options And Performance Award Fair Value Assumptions

The Company calculated the fair value of stock options on the date of grant using the Black-Scholes-Merton model and the assumptions listed below:

	March 2016 Grant			March 2015 Grant			February 2014 Grant
Grant date price per share of stock option award	$	18.11		$	17.57		$	37.93
Expected dividend yield per share		0.00	%		3.40	%		2.75	%
Expected life in years		5.96			5.75			6.5
Expected volatility		40.86	%		42.27	%		52.14	%
Risk-free interest rate		1.45	%		1.73	%		1.98	%
Grant date fair value per share of option awards	$	7.41		$	5.20		$	15.26

Summary of Performance Stock Units

The following table shows a summary of the performance stock units as of December 31, 2016:

Performance Period	Minimum Shares		Target Shares		Maximum Shares
2014 – 2016		0		87,262		130,893
2015 – 2017		0		203,953		407,906
2016 – 2018		0		260,588		521,176

Summary of Status and Activity of Non-Vested Stock Awards

The following table shows a summary of the status and activity of non-vested stock awards for the year ended December 31, 2016:

	Restricted Stock Units			Performance Stock Units			Total Stock Units			Weighted Average Grant Date Fair Value per Unit
Non-vested at January 1, 2016		213,208			397,399			610,607		$	27.29
Granted		178,282			264,981			443,263		$	22.25
Credited from dividends		950			1,712			2,662		$	25.47
Vested		(100,281	)		0			(100,281	)	$	28.77
Forfeited		(12,352	)		(109,704	)		(122,056	)	$	36.46
Non-vested at December 31, 2016		279,807			554,388			834,195		$	23.09

Summary of Status and Activity of Stock Options

The following table shows a summary of the status and activity of stock options for the year ended December 31, 2016:

	Options			Weighted Average Exercise Price per Option		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in millions)
Outstanding at December 31, 2015		774,249		$	28.46
Granted		211,193		$	18.11
Exercised		(15,901	)	$	24.94
Expired		(14,548	)	$	40.38
Forfeited		(19,539	)	$	23.70
Outstanding at December 31, 2016		935,454		$	26.10		6.46	$	6.0
Exercisable at December 31, 2016		436,582		$	33.07		4.14	$	3.3

Schedule of Stock-based Compensation Expense Recognized and Cash Received from Exercise of Stock Options

Total stock-based compensation expense recognized and cash received from the exercise of stock options for the three years ended December 31, 2016, 2015 and 2014 are as follows:

	Year Ended December 31,
	2016		2015		2014
(Dollars in millions)
Stock-based compensation expense recognized:
Selling, general and administrative expenses	$	8.9	$	3.8	$	4.7
Less related income tax benefit		3.6		1.5		1.9
Decrease in net income attributable to Koppers	$	5.3	$	2.3	$	2.8
Intrinsic value of exercised stock options	$	0.1	$	0.0	$	0.3
Cash received from the exercise of stock options	$	0.4	$	0.0	$	0.7

Performance Stock Units [Member]

Stock Options And Performance Award Fair Value Assumptions

The Company calculated the fair value of the awards on the date of grant using the Monte Carlo valuation model and the assumptions listed below:

	March 2016 Grant
Grant date price per share of performance award	$	18.11
Expected dividend yield per share		0.00	%
Expected volatility		40.86	%
Risk-free interest rate		0.96	%
Look-back period in years		2.84
Grant date fair value per share of performance award	$	23.70

Segment Information (Tables)

12 Months Ended

Dec. 31, 2016

Segment Reporting [Abstract]

Summary of Results of Segment Operations

The following table sets forth certain sales and operating data, net of all intersegment transactions, for the Company’s segments for the periods indicated:

	Year Ended December 31,
	2016			2015			2014
(Dollars in millions)
Revenues from external customers:
Railroad and Utility Products and Services	$	586.5		$	657.0		$	597.8
Carbon Materials and Chemicals		436.3			613.4			833.7
Performance Chemicals		393.4			356.5			123.5
Total	$	1,416.2		$	1,626.9		$	1,555.0
Intersegment revenues:
Carbon Materials and Chemicals	$	90.2		$	86.7		$	84.8
Performance Chemicals		8.1			8.7			3.0
Total	$	98.3		$	95.4		$	87.8
Depreciation and amortization expense:
Railroad and Utility Products and Services^(a)	$	13.0		$	14.2		$	11.9
Carbon Materials and Chemicals^(b)		21.2			25.8			25.0
Performance Chemicals		18.7			19.0			7.1
Total	$	52.9		$	59.0		$	44.0
Operating profit (loss):
Railroad and Utility Products and Services^(c)	$	51.1		$	62.2		$	53.6
Carbon Materials and Chemicals^(d)		(25.1	)		(125.0	)		(5.3	)
Performance Chemicals		62.0			39.0			1.6
Corporate^(e)		(1.6	)		(5.8	)		(16.7	)
Total	$	86.4		$	(29.6	)	$	33.2
Capital expenditures (including acquisitions):
Railroad and Utility Products and Services	$	11.2		$	11.1		$	44.5
Carbon Materials and Chemicals		29.5			37.6			63.7
Performance Chemicals		7.9			5.8			471.1
Corporate		1.3			1.5			0.7
Total	$	49.9		$	56.0		$	580.0

(a)	Excludes impairment charges of $1.9 million in 2015 for a wood treating facility in the United States.

(b) Excludes impairment charges of $3.5, $12.8 and $4.7 million in 2016, 2015 and 2014, respectively, for CMC.

(d)	Includes plant closure costs of $13.2, $36.5 and $18.1 million in 2016, 2015 and 2014, respectively, for CMC. In the fourth quarter of 2015, the Company also recorded goodwill impairment charges of $67.2 million related to this business unit.

(e)

Summary of Tangible and Intangible Assets by Segments

The following table sets forth tangible and intangible assets allocated to each of the Company’s segments as of the dates indicated:

	December 31, 2016		December 31, 2015
(Dollars in millions)
Segment assets:
Railroad and Utility Products and Services	$	264.2	$	254.1
Carbon Materials and Chemicals		333.0		368.4
Performance Chemicals		442.9		441.3
Segment assets		1,040.1		1,063.8
Cash and cash equivalents		0.0		0.1
Income tax receivable		3.8		4.6
Deferred taxes		32.5		32.6
Property, plant and equipment, net		4.9		4.7
Deferred charges		0.7		1.6
Other		5.5		5.4
Total	$	1,087.5	$	1,112.9
Goodwill:
Railroad and Utility Products and Services	$	9.9	$	9.9
Performance Chemicals		176.5		176.7
Total	$	186.4	$	186.6

Schedule of Revenues and Long-Lived Assets by Geographic Area

Revenues and Long-lived Assets by Geographic Area

	Year		Revenue		Long-lived assets
(Dollars in millions)
United States		2016	$	929.3	$	446.6
		2015		991.2		460.3
		2014		833.0		518.8
Australasia		2016		228.4		124.3
		2015		280.9		132.9
		2014		349.0		160.3
Europe		2016		140.2		31.9
		2015		144.0		32.9
		2014		201.1		47.5
Other countries		2016		118.3		19.5
		2015		210.8		18.3
		2014		171.9		18.3
Total		2016	$	1,416.2	$	622.3
		2015	$	1,626.9	$	644.5
		2014	$	1,555.0	$	744.9

Schedule of Segment Revenues for Significant Product Lines

Segment Revenues for Significant Product Lines

	Year Ended December 31,
	2016		2015		2014
(Dollars in millions)
Railroad and Utility Products and Services:
Railroad crossties	$	374.0	$	422.0	$	371.4
Utility poles		34.5		52.4		96.1
Creosote		49.6		45.7		51.2
Rail joints		24.4		28.1		27.2
Railroad infrastructure services		43.4		42.7		14.8
Other products		60.6		66.1		37.1
		586.5		657.0		597.8
Carbon Materials and Chemicals:
Carbon pitch		191.0		283.4		330.2
Phthalic anhydride		75.6		65.1		91.4
Creosote and carbon black feedstock		71.3		119.6		213.7
Other products		98.4		145.3		198.4
		436.3		613.4		833.7
Performance Chemicals:
Wood preservative products		365.5		318.6		107.0
Other products		27.9		37.9		16.5
		393.4		356.5		123.5
Total	$	1,416.2	$	1,626.9	$	1,555.0

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Summary of Income Tax Provision

Components of the Company’s income tax provision from continuing operations are as follows:

	Year Ended December 31,
	2016			2015			2014
(Dollars in millions)
Current:
Federal	$	(1.9	)	$	(4.2	)	$	17.5
State		1.3			0.2			0.3
Foreign		13.3			16.0			14.6
Total current tax provision		12.7			12.0			32.4
Deferred:
Federal		(1.6	)		(19.2	)		3.1
State		0.5			3.0			0.0
Foreign		(0.2	)		0.0			(1.4	)
Total deferred tax (benefit) provision		(1.3	)		(16.2	)		1.7
Total income tax (benefit) provision	$	11.4		$	(4.2	)	$	34.1

Summary of Income Taxes Reconciled with Federal Statutory Rate

The provision for income taxes is reconciled with the federal statutory rate as follows:

	Year Ended December 31,
	2016			2015			2014
Federal income tax rate		35.0	%		35.0	%		35.0	%
State income taxes, net of federal tax benefit		(0.8	)		2.3			(4.8	)
Foreign earnings taxed at different rates		(10.1	)		(8.3	)		(347.6	)
Domestic production activities deduction	0.0				(0.6	)		40.8
Deferred tax adjustments		(0.2	)		0.4			3.2
Change in tax contingency reserves		6.5			1.5			(15.2	)
Legal entity tax restructuring project	0.0			0.0				(1,503.2	)
Foreign tax credits	0.0			0.0				1,203.4
Changes to foreign repatriation plans	0.0			0.0				104.0
Valuation allowance charges		(1.9	)		(13.0	)		(92.4	)
Goodwill impairment	0.0				(10.9	)	0.0
Other		1.1			(1.1	)		(1.2	)
		29.6	%		5.3	%		(578.0	%)

Summary of Deferred Tax Assets and Liabilities

Significant components of the Company’s deferred tax assets and liabilities are as follows:

	Year Ended December 31,
	2016			2015
(Dollars in millions)
Deferred tax assets:
Reserves, including insurance, environmental and deferred revenue	$	22.3		$	19.9
Pension and other postretirement benefits obligations		19.2			19.4
Tax credits		15.4			16.8
Asset retirement obligations		12.0			12.0
State tax losses carryforwards (expiring from 2017-2036)		11.3			10.2
Foreign tax loss carryforwards (expiring beginning in 2018)		10.1			9.3
Accrued employee compensation		8.9			6.9
Book/tax inventory accounting differences		3.5			3.2
Capital loss benefit		0.0			0.9
Book over tax depreciation and amortization		0.0			3.6
Other		6.6			10.0
Valuation allowance		(40.2	)		(41.9	)
Total deferred tax assets		69.1			70.3
Deferred tax liabilities:
Tax over book depreciation and amortization		42.7			38.4
Gain on derivative contracts		4.2			0.0
Tax/book inventory accounting differences		0.0			0.3
Other		1.4			0.7
Total deferred tax liabilities		48.3			39.4
Net deferred tax assets	$	20.8		$	30.9

Summary of Valuation Allowances Recorded to Offset Deferred Tax Assets

	Year Ended December 31,
	2016		2015
Federal foreign tax credits	$	14.3	$	14.9
State temporary differences, net operating losses and tax credits		13.2		11.6
Foreign temporary differences, net operating losses and capital losses		12.7		15.4
Total valuation allowances	$	40.2	$	41.9

Summary of Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:

	Year Ended December 31,
	2016			2015			2014
(Dollars in millions)
Balance at beginning of year	$	7.7		$	7.2		$	6.1
Additions based on tax provisions related to the current year		0.9			1.4			0.6
Additions for tax provisions of prior years		1.5			0.0			0.1
Additions as a result of acquisitions		0.0			0.0			1.6
Reductions of tax provisions of prior years		0.0			(0.7	)		(0.6	)
Reductions as a result of a lapse of the applicable statute of limitations		(0.4	)		(0.2	)		(0.6	)
Balance at end of year	$	9.7		$	7.7		$	7.2

Inventories (Tables)

12 Months Ended

Dec. 31, 2016

Inventory Disclosure [Abstract]

Components of Inventories

Inventories as of December 31, 2016 and 2015 were as follows:

	December 31, 2016		December 31, 2015
(Dollars in millions)
Raw materials	$	157.7	$	169.8
Work in process		14.2		15.5
Finished goods		103.6		97.4
		275.5		282.7
Less revaluation to LIFO		46.8		56.3
Net	$	228.7	$	226.4

Equity Investments (Tables)

12 Months Ended

Dec. 31, 2016

Equity Method Investments And Joint Ventures [Abstract]

Equity Losses and Dividends Received

Equity in losses for the three years ended December 31, 2016 were as follows:

	Equity loss
(Dollars in millions)
2016	$	(1.0	)
2015		(2.2	)
2014		(1.6	)

Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2016

Property Plant And Equipment [Abstract]

Property, Plant and Equipment

Property, plant and equipment as of December 31, 2016 and 2015 were as follows:

	December 31, 2016		December 31, 2015
(Dollars in millions)
Land	$	17.0	$	17.6
Buildings		58.2		61.8
Machinery and equipment		716.0		669.0
	$	791.2	$	748.4
Less accumulated depreciation		510.4		470.6
Net	$	280.8	$	277.8

Goodwill and Other Identifiable Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2016

Goodwill And Intangible Assets Disclosure [Abstract]

Changes in Carrying Amount of Goodwill

The change in the carrying amount of goodwill attributable to each business segment for the years ended December 31, 2016 and December 31, 2015 was as follows:

	Carbon Materials and Chemicals			Railroad and Utility Products and Services			Performance Chemicals			Total
(Dollars in millions)
Balance at December 31, 2014	$	65.5		$	9.3		$	172.4		$	247.2
Acquisitions		4.1			0.0			0.0			4.1
Purchase price allocation adjustments		0.0			1.2			8.3			9.5
Impairment		(67.2	)		0.0			0.0			(67.2	)
Currency translation		(2.4	)		(0.6	)		(4.0	)		(7.0	)
Balance at December 31, 2015	$	0.0		$	9.9		$	176.7		$	186.6
Currency translation		0.0			0.0			(0.2	)		(0.2	)
Balance at December 31, 2016	$	0.0		$	9.9		$	176.5		$	186.4

Schedule of Identifiable Intangible Assets

The Company’s identifiable intangible assets with finite lives are being amortized over their estimated useful lives and are summarized below:

					December 31,
					2016						2015
	Estimated life in years		Weighted average remaining life in years		Gross Carrying Amount		Accumulated Amortization		Net		Gross Carrying Amount		Accumulated Amortization		Net
(Dollars in millions)
Customer contracts	9 to 18			13.2	$	152.5	$	33.6	$	118.9	$	153.0	$	24.3	$	128.7
Technology	4 to 12			5.0		26.7		8.8		17.9		26.6		5.1		21.5
Trademarks	4 to 7			4.6		6.1		1.9		4.2		5.9		1.1		4.8
Supply contracts		10		3.2		2.2		1.5		0.7		2.3		1.4		0.9
Non-compete agreements		12		7.8		1.3		1.1		0.2		1.4		1.2		0.2
Favorable lease agreements		3		0.0		0.6		0.6		0.0		0.7		0.7		0.0
Total				11.9	$	189.4	$	47.5	$	141.9	$	189.9	$	33.8	$	156.1

Schedule of Future Amortization Expense

Estimated amortization expense for the next five years is summarized below:

	Estimated annual amortization
(Dollars in millions)
2017	$	14.3
2018		14.3
2019		14.3
2020		14.0
2021		12.1

Pensions and Post-Retirement Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2016

Compensation And Retirement Disclosure [Abstract]

Components of Net Periodic Benefit Cost for Pension Plans and Other Benefit Plans

Net periodic pension costs for 2016, 2015 and 2014 were as follows:

	December 31,
	Pension Benefits									Other Benefits
	2016			2015			2014			2016			2015			2014
(Dollars in millions)
Service cost	$	1.7		$	2.0		$	2.7		$	0.1		$	0.1		$	0.1
Interest cost		11.0			10.9			11.8			0.4			0.4			0.5
Expected return on plan assets		(10.5	)		(12.0	)		(13.9	)		0.0			0.0			0.0
Amortization of prior service cost		0.0			(0.3	)		(0.2	)		0.0			(0.1	)		(0.2	)
Amortization of net loss		2.2			6.6			4.0			(0.4	)		(0.3	)		0.0
Settlements and curtailments		4.4			(0.8	)		0.0			0.0			0.0			0.0
Net periodic benefit cost	$	8.8		$	6.4		$	4.4		$	0.1		$	0.1		$	0.4

Schedule of Change in Funded Status of Pension and Post-Retirement Plans

The change in the funded status of the pension and postretirement plans as of December 31, 2016 and December 31, 2015 is as follows:

	December 31,
	Pension Benefits						Other Benefits
	2016			2015			2016			2015
(Dollars in millions)
Change in benefit obligation:
Benefit obligation at beginning of year	$	257.5		$	275.7		$	9.4		$	9.8
Service cost		1.7			2.0			0.1			0.1
Interest cost		11.0			10.9			0.4			0.4
Plan participants’ contributions		0.1			0.2			0.0			0.0
Actuarial losses (gains)		10.7			(14.9	)		1.0			(0.3	)
Plan amendments		(0.1	)		0.0			0.0			0.0
Settlements		(13.9	)		0.0			0.0			0.0
Currency translation		(9.9	)		(3.4	)		0.0			0.0
Benefits paid		(13.5	)		(13.0	)		(0.9	)		(0.6	)
Benefit obligation at end of year		243.6			257.5			10.0			9.4
Change in plan assets:
Fair value of plan assets at beginning of year		212.4			229.5			0.0			0.0
Actual return on plan assets		20.8			(4.6	)		0.0			0.0
Employer contribution		4.4			3.4			0.9			0.6
Plan participants’ contributions		0.1			0.2			0.0			0.0
Settlements		(13.9	)		0.0			0.0			0.0
Currency translation		(9.4	)		(3.1	)		0.0			0.0
Benefits paid		(13.5	)		(13.0	)		(0.9	)		(0.6	)
Fair value of plan assets at end of year		200.9			212.4			0.0			0.0
Funded status of the plan	$	(42.7	)	$	(45.1	)	$	(10.0	)	$	(9.4	)
Amounts recognized in the balance sheet consist of:
Noncurrent assets	$	0.8		$	0.8		$	0.0		$	0.0
Current liabilities		1.1			0.9			0.8			0.8
Noncurrent liabilities		42.4			45.0			9.2			8.6
Pension plans with projected benefit obligations in excess of plan assets:
Benefit obligation	$	238.7		$	252.7
Fair value of plan assets		195.3			206.9
Pension plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligation	$	238.5		$	251.2
Fair value of plan assets		195.3			206.9

Schedule of Projected Benefit Payments

	Pension Benefits		Other Benefits
(Dollars in millions)
2017	$	13.0	$	0.9
2018		12.9		0.9
2019		13.2		0.8
2020		13.5		0.8
2021		13.8		0.7
Next five years		75.0		3.1

Schedule of Weighted-Average Assumptions

Weighted-Average Assumptions as of December 31

	December 31,
	Pension Benefits						Other Benefits
	2016			2015			2016			2015
Discount rate		4.09	%		4.52	%		4.53	%		4.73	%
Expected return on plan assets		5.10			5.16
Rate of compensation increase		3.50			3.82
Initial medical trend rate								6.30			6.50

Schedule of Weighted Average Asset Allocation for Company's Pension Plans

The weighted average asset allocation for the Company’s pension plans at December 31 by asset category is as follows:

	December 31,
	2016			2015
Debt securities		71	%		70	%
Equity securities		24			26
Other		5			4
		100	%		100	%

Schedule of Pension Plan Assets at Fair Value

The following table sets forth by level, the Company’s pension plan assets at fair value, within the fair value hierarchy, as of December 31, 2016 and December 31, 2015:

	As of December 31, 2016
	Quoted prices
	in active		Significant		Significant
	markets for		observable		unobservable
	identical assets		inputs		inputs
	(Level 1)		(Level 2)		(Level 3)		Total
(Dollars in millions)
U.S. equity securities	$	12.3	$	13.2		0.0	$	25.5
International equity securities		12.6		10.9		0.0		23.5
U.S. debt securities		29.7		75.2		3.2		108.1
International debt securities		8.3		24.3		1.1		33.7
Real estate and other investments		0.0		0.5		5.7		6.2
Cash and cash equivalents		0.0		3.9		0.0		3.9
	$	62.9	$	128.0	$	10.0	$	200.9

	As of December 31, 2015
	Quoted prices
	in active		Significant		Significant
	markets for		observable		unobservable
	identical assets		inputs		inputs
	(Level 1)		(Level 2)		(Level 3)		Total
(Dollars in millions)
U.S. equity securities	$	15.0	$	10.2	$	0.0	$	25.2
International equity securities	12.1			18.6		0.0	30.7
U.S. debt securities	32.3		84.8			0.0	117.1
International debt securities		7.0	25.5			0.0	32.5
Real estate and other investments		0.0	1.4			0.0	1.4
Cash and cash equivalents		0.0	5.5			0.0	5.5
	$	66.4	$	146.0	$	0.0	$	212.4

Summary of Changes in Fair Value of Level 3 Pension Plan Assets

The table below sets forth a summary of changes in the fair value of the Level 3 pension plans’ assets for the year ended December 31, 2016:

	As of December 31, 2016
	Other Investments			Debt Securities
(Dollars in millions)
Balance at beginning of year	$	0.0		$	0.0
Purchases, sales, issuances and settlements	4.4				6.0
Realized and unrealized gains	0.2			0.1
Foreign currency translation loss		(0.3	)		(0.4	)
Balance at the end of year	$	4.3		$	5.7
The amount of total gains during the period attributable to the change in unrealized gains relating to Level 3 net assets still held at the reporting date	$	0.2		$	0.1

Schedule of Health Care Cost Trend Rates

A one-percentage-point change in the assumed health care cost trend rate would have the following effects:

	1% Increase		1% Decrease
(Dollars in millions)
Increase (decrease) from change in health care cost trend rates:
Postretirement benefit expense	$	0.0	$	0.0
Postretirement benefit liability		0.2		(0.1	)

Debt (Tables)

12 Months Ended

Dec. 31, 2016

Debt Disclosure [Abstract]

Schedule of Long-Term Debt Instruments

Debt at December 31, 2016 and December 31, 2015 was as follows:

	Weighted Average Interest Rate			Maturity	December 31, 2016		December 31, 2015
(Dollars in millions)
Term Loan		4.57	%	2019	$	232.5	$	262.5
Revolving Credit Facility		4.57	%	2019		100.1		130.0
Construction and other loans		4.87	%	2020		40.4		44.8
Senior Notes due 2019		7.88	%	2019		298.1		297.5
Total debt						671.1		734.8
Less short term debt and current maturities of long-term debt						42.6		39.9
Less unamortized debt issuance costs						8.7		12.5
Long-term debt					$	619.8	$	682.4

Schedule of Debt Maturities

At December 31, 2016 the aggregate debt maturities for the next five years are as follows:


(Dollars in millions)
2017	$	42.6
2018		37.0
2019 ⁽¹⁾		575.3
2020		18.1
Total maturities		673.0
Future accretion on 2019 Notes		(1.9	)
Total debt	$	671.1

(1)	Consists primarily of the maturity of the 2019 Notes and Prior Senior Secured Credit Facilities. The $500.0 million Senior Notes offered in January 2017 mature in 2025. The $400.0 million New Senior Secured Credit Facility entered in February 2017 will mature in 2022.

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21538-112644

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28541-108399

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644

+ Details

Leases (Tables)

12 Months Ended

Dec. 31, 2016

Leases [Abstract]

Future Minimum Commitments for Operating Leases

Future minimum commitments for operating leases having non-cancelable lease terms in excess of one year are as follows:

(Dollars in millions)
2017	$	43.9
2018		34.0
2019		17.3
2020		13.6
2021		11.7
Thereafter		46.8
Total	$	167.3

Derivative Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2016

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Schedule of Outstanding Copper Swap Contracts

As of December 31, 2016 and December 31, 2015, the Company had outstanding copper swap contracts of the following amounts:

	Units Outstanding (in Pounds)		Net Fair Value - Asset (Liability)
	December 31, 2016	December 31, 2015	December 31, 2016		December 31, 2015
(Amounts in millions)
Cash flow hedges	42.6	17.3	$	10.6	$	(9.8	)
Not designated as hedges	6.5	4.0		1.0		(0.7	)
Total	49.1	21.3	$	11.6	$	(10.5	)

Schedule of Fair Value of Outstanding Copper Swap Contracts Recorded in Balance Sheet

As of December 31, 2016 and December 31, 2015, the fair value of the outstanding copper swap contracts is recorded in the balance sheet as follows:

	December 31, 2016			December 31, 2015
(Dollars in millions)
Other current assets	$	12.5		$	0.1
Accrued liabilities		(0.9	)		(10.6	)
Net asset (liability) on balance sheet	$	11.6		$	(10.5	)
Accumulated other comprehensive gain (loss), net of tax	$	6.9		$	(6.1	)

Summary of Amount Recognized in Earnings Related to Copper Swap Contracts

	Twelve Months Ended December 31,
	2016			2015
(Dollars in millions)
Gain (loss) from ineffectiveness of cash flow hedges	$	(0.4	)	$	(0.1	)
Gain (loss) from contracts not designated as hedges		1.7			(0.7	)
Net	$	1.3		$	(0.8	)

Summary of Net Currency Units Outstanding

As of December 31, 2016 and December 31 2015, the net currency units outstanding were:

	December 31, 2016		December 31, 2015
(In millions)
British Pounds		GBP 7.3		GBP 5.9
New Zealand Dollars		NZD 15.5		NZD 22.5
United States Dollars		USD 24.7		USD 40.0
Canadian Dollars		CAD 0.3		CAD 0.0

Common Stock and Senior Convertible Preferred Stock (Tables)

12 Months Ended

Dec. 31, 2016

Text Block [Abstract]

Schedule of Changes in Senior Convertible Preferred Stock, Common Stock and Treasury Stock

Changes in senior convertible preferred stock, common stock and treasury stock for the three years ended December 31, 2016 are as follows:

	Year Ended December 31,
	2016			2015			2014
(Shares in thousands)
Senior Convertible Preferred Stock:
Balance at beginning and end of year		0			0			0
Common Stock:
Balance at beginning of year		22,016			21,938			21,722
Issued for employee stock plans		125			78			216
Balance at end of year		22,141			22,016			21,938
Treasury Stock:
Balance at beginning of year		(1,459	)		(1,443	)		(1,390	)
Shares repurchased		(17	)		(16	)		(53	)
Balance at end of year		(1,476	)		(1,459	)		(1,443	)

- Definition

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=65877616&loc=d3e177068-122764

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(d))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21553-112644

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65888546&loc=d3e21300-112643

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(27))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21538-112644

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

+ Details

Commitments and Contingent Liabilities (Tables)

12 Months Ended

Dec. 31, 2016

Commitments And Contingencies Disclosure [Abstract]

Changes in Accrued Liability for Environmental Matters

The following table reflects changes in the accrued liability for environmental matters, of which $5.2 million and $7.0 million are classified as current liabilities at December 31, 2016 and 2015, respectively

	Year ended
	December 31, 2016			December 31, 2015
(Dollars in millions)
Balance at beginning of year	$	19.8		$	7.8
Expense		1.5			1.2
Reversal of reserves		(1.0	)		(0.5	)
Cash expenditures		(6.3	)		(1.4	)
Acquisition of Osmose Entities		0.0			13.7
Divestitures		(0.3	)		0.0
Currency translation		(0.8	)		(1.0	)
Balance at end of period	$	12.9		$	19.8

Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2016

Quarterly Financial Information Disclosure [Abstract]

Schedule of Selected Quarterly Financial Data

The following is a summary of the quarterly results of operations for the years ended December 31, 2016 and 2015:

	Year Ended December 31, 2016
	1^stQuarter			2^nd Quarter		3^rd Quarter		4^th Quarter		Fiscal Year
(Dollars in millions, except per share amounts)
Statement of operations data:
Net sales	$	346.8		$	385.1	$	371.1	$	313.2	$	1,416.2
Operating profit		7.8			32.0		27.7		18.9		86.4
Income (loss) from continuing operations		(2.4	)		11.3		12.0		6.2		27.1
Net income (loss)		(1.8	)		11.3		11.9		6.3		27.7
Net income (loss) attributable to Koppers		(1.3	)		12.1		12.1		6.4		29.3
Common stock data:
Earnings (loss) per common share attributable to Koppers common shareholders: ^(b)
Basic –
Continuing operations	$	(0.09	)	$	0.58	$	0.59	$	0.31	$	1.39
Discontinued operations		0.03			0.00		0.00		0.00		0.03
Earnings (loss) per basic common share	$	(0.06	)	$	0.58	$	0.59	$	0.31	$	1.42
Diluted –
Continuing operations	$	(0.09	)	$	0.57	$	0.58	$	0.30	$	1.36
Discontinued operations		0.03			0.00		0.00		0.00		0.03
Earnings (loss) per diluted common share	$	(0.06	)	$	0.57	$	0.58	$	0.30	$	1.39
Price range of common stock:
High	$	23.43		$	31.35	$	33.71	$	42.70	$	42.70
Low		13.58			21.38		28.54		31.28		13.58

	Year Ended December 31, 2015
	1^stQuarter			2^nd Quarter		3^rd Quarter			4^th Quarter			Fiscal Year
(Dollars in millions, except per share amounts)
Statement of operations data:
Net sales	$	397.8		$	431.6	$	433.8		$	363.7		$	1,626.90
Operating (loss) profit^(a)		8.0			26.0		27.0			(90.6	)		(29.6	)
(Loss) income from continuing operations		(4.2	)		7.9		9.2			(88.8	)		(75.9	)
Net (loss) income		(4.2	)		7.9		9.1			(88.8	)		(76.0	)
Net (loss) income attributable to Koppers		(3.4	)		9.0		10.1			(87.7	)		(72.0	)
Common stock data:
(Loss) earnings per common share attributable to Koppers common shareholders: ^(b)
Basic –
Continuing operations	$	(0.16	)	$	0.44	$	0.49		$	(4.27	)	$	(3.50	)
Discontinued operations		0.00			0.00		(0.01	)		0.00			(0.01	)
(Loss) earnings per basic common share	$	(0.16	)	$	0.44	$	0.48		$	(4.27	)	$	(3.51	)
Diluted –
Continuing operations	$	(0.16	)	$	0.44	$	0.49		$	(4.27	)	$	(3.50	)
Discontinued operations		0.00			0.00		(0.01	)		0.00			(0.01	)
(Loss) earnings per diluted common share	$	(0.16	)	$	0.44	$	0.48		$	(4.27	)	$	(3.51	)
Price range of common stock:
High	$	26.44		$	27.40	$	24.86		$	23.63		$	27.40
Low		15.78			19.26		17.88			17.34			15.78

(a)

Subsidiary Guarantor Information for Koppers Inc. 2025 Notes and Shelf Registration (Tables)

12 Months Ended

Dec. 31, 2016

Debt Disclosure [Abstract]

Condensed Consolidating Statement of Comprehensive Income (Loss)

For the Year Ended December 31, 2016

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries		Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Net sales	$	0.0		$	660.7		$	350.6	$	504.7		$	(99.8	)	$	1,416.2
Cost of sales including depreciation and amortization		0.0			637.4			252.3		412.4			(101.2	)		1,200.9
Gain on sale of business		0.0			0.0			0.0		(2.1	)		0.0			(2.1	)
Selling, general and administrative		1.9			47.7			38.2		43.2			0.0			131.0
Operating (loss) profit		(1.9	)		(24.4	)		60.1		51.2			1.4			86.4
Other income (loss)		0.0			0.3			4.1		0.3			(1.8	)		2.9
Equity income of subsidiaries		30.6			79.1			35.9		0.0			(145.6	)		0.0
Interest (income) expense		0.0			47.6			0.0		5.0			(1.8	)		50.8
Income taxes		(0.6	)		(23.2	)		22.2		13.0			0.0			11.4
Income from continuing operations		29.3			30.6			77.9		33.5			(144.2	)		27.1
Discontinued operations		0.0			0.0			0.0		0.6			0.0			0.6
Noncontrolling interests		0.0			0.0			0.0		(1.6	)		0.0			(1.6	)
Net income attributable to Koppers	$	29.3		$	30.6		$	77.9	$	35.7		$	(144.2	)	$	29.3
Comprehensive income (loss) attributable to Koppers	$	40.5		$	41.3		$	85.0	$	29.6		$	(155.9	)	$	40.5

Condensed Consolidating Statement of Comprehensive (Loss) Income

For the Year Ended December 31, 2015

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Net sales	$	0.0		$	791.1		$	335.6		$	600.9		$	(100.7	)	$	1,626.9
Cost of sales including depreciation and amortization		0.0			771.7			233.2			562.4			(99.4	)		1,467.9
Gain on sale of business		0.0			(3.2	)		0.0			0.0			0.0			(3.2	)
Goodwill impairment		0.0			43.1			24.1			0.0			0.0			67.2
Selling, general and administrative		1.9			41.3			37.8			43.6			0.0			124.6
Operating (loss) profit		(1.9	)		(61.8	)		40.5			(5.1	)		(1.3	)		(29.6	)
Other income (loss)		0.0			0.5			4.1			(2.4	)		(2.0	)		0.2
Equity income of subsidiaries		(70.8	)		0.9			(27.9	)		0.0			97.8			0.0
Interest expense		0.0			45.8			0.0			6.9			(2.0	)		50.7
Income taxes		(0.7	)		(35.4	)		15.8			16.4			(0.3	)		(4.2	)
(Loss) income from continuing operations		(72.0	)		(70.8	)		0.9			(30.8	)		96.8			(75.9	)
Discontinued operations		0.0			0.0			0.0			(0.1	)		0.0			(0.1	)
Noncontrolling interests		0.0			0.0			0.0			(4.0	)		0.0			(4.0	)
Net income attributable to Koppers	$	(72.0	)	$	(70.8	)	$	0.9		$	(26.9	)	$	96.8		$	(72.0	)
Comprehensive income (loss) attributable to Koppers	$	(91.5	)	$	(90.3	)	$	(18.1	)	$	(41.8	)	$	150.2		$	(91.5	)

Condensed Consolidating Statement of Comprehensive (Loss) Income

For the Year Ended December 31, 2014

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Net sales	$	0.0		$	795.9		$	143.0		$	683.5		$	(67.4	)	$	1,555.0
Cost of sales including depreciation and amortization		0.0			724.5			108.8			639.0			(66.7	)		1,405.6
Selling, general and administrative		2.2			59.2			17.4			37.4			0.0			116.2
Operating (loss) profit		(2.2	)		12.2			16.8			7.1			(0.7	)		33.2
Other income (loss)		0.0			0.2			4.7			(0.6	)		(4.3	)		0.0
Equity income of subsidiaries		(31.0	)		(15.9	)		(6.4	)		0.0			53.3			0.0
Interest expense		0.0			36.5			0.0			6.9			(4.3	)		39.1
Income taxes		(0.8	)		(9.0	)		30.5			13.4			0.0			34.1
Income from continuing operations		(32.4	)		(31.0	)		(15.4	)		(13.8	)		52.6			(40.0	)
Discontinued operations		0.0			0.0			(0.6	)		1.2			0.0			0.6
Noncontrolling interests		0.0			0.0			0.0			(7.0	)		0.0			(7.0	)
Net income attributable to Koppers	$	(32.4	)	$	(31.0	)	$	(16.0	)	$	(5.6	)	$	52.6		$	(32.4	)
Comprehensive income (loss) attributable to Koppers	$	(82.5	)	$	(81.1	)	$	(54.4	)	$	(35.1	)	$	170.6		$	(82.5	)

Condensed Consolidating Balance Sheet

December 31, 2016

	Parent		Koppers Inc.		Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries		Consolidating Adjustments			Consolidated
(Dollars in millions)
ASSETS
Cash and cash equivalents	$	0.0	$	0.0	$	0.0		$	20.8	$	0.0		$	20.8
Receivables, net		0.0		50.8		25.4			64.4		0.0			140.6
Affiliated receivables		0.7		34.8		32.2			15.4		(83.1	)		0.0
Inventories, net		0.0		106.6		23.9			99.0		(0.8	)		228.7
Other current assets		0.0		5.1		13.4			29.2		0.3			48.0
Total current assets		0.7		197.3		94.9			228.8		(83.6	)		438.1
Equity investments		29.9		697.4		195.4			0.0		(922.7	)		0.0
Property, plant and equipment, net		0.0		126.7		39.6			114.5		0.0			280.8
Goodwill		0.0		0.8		153.1			32.5		0.0			186.4
Intangible assets, net		0.0		7.9		107.1			26.9		0.0			141.9
Deferred tax assets		0.0		29.7		(8.4	)		5.8		0.0			27.1
Affiliated loan receivables		0.0		36.9		205.3			21.9		(264.1	)		0.0
Other assets		0.0		5.5		6.1			1.6		0.0			13.2
Total assets	$	30.6	$	1,102.2	$	793.1		$	432.0	$	(1,270.4	)	$	1,087.5
LIABILITIES AND EQUITY
Accounts payable	$	0.2	$	69.6	$	38.9		$	35.5	$	0.0		$	144.2
Affiliated payables		0.0		46.0		20.7			24.5		(91.2	)		0.0
Accrued liabilities		0.0		49.5		18.9			37.9		0.0			106.3
Current maturities of long-term debt		0.0		30.2		0.0			12.4		0.0			42.6
Total current liabilities		0.2		195.3		78.5			110.3		(91.2	)		293.1
Long-term debt		0.0		592.0		0.0			27.8		0.0			619.8
Affiliated debt		0.0		209.9		23.5			30.7		(264.1	)		0.0
Other long-term liabilities		0.0		75.0		11.6			53.4		0.0			140.0
Total liabilities		0.2		1,072.2		113.6			222.2		(355.3	)		1,052.9
Koppers shareholders’ equity		30.4		30.0		679.5			205.6		(915.1	)		30.4
Noncontrolling interests		0.0		0.0		0.0			4.2		0.0			4.2
Total liabilities and equity	$	30.6	$	1,102.2	$	793.1		$	432.0	$	(1,270.4	)	$	1,087.5

Condensed Consolidating Balance Sheet

December 31, 2015

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries		Non-Guarantor Subsidiaries		Consolidating Adjustments			Consolidated
(Dollars in millions)
ASSETS
Cash and cash equivalents	$	0.0		$	0.1		$	0.7	$	21.0	$	0.0		$	21.8
Receivables, net		0.0			60.4			23.7		75.5		0.0			159.6
Affiliated receivables		0.0			14.3			15.2		4.4		(33.9	)		0.0
Inventories, net		0.0			111.9			24.9		91.8		(2.2	)		226.4
Deferred tax assets		0.0			0.0			0.0		0.0		0.0			0.0
Other current assets		0.0			3.7			1.9		30.9		0.0			36.5
Total current assets		0.0			190.4			66.4		223.6		(36.1	)		444.3
Equity investments		(19.0	)		703.2			165.7		0.0		(849.9	)		0.0
Property, plant and equipment, net		0.0			117.5			41.2		119.1		0.0			277.8
Goodwill		0.0			0.8			153.1		32.7		0.0			186.6
Intangible assets, net		0.0			8.7			117.6		29.8		0.0			156.1
Deferred tax assets		0.0			29.8			0.8		5.7		0.3			36.6
Affiliated loan receivables		0.7			29.6			222.6		31.7		(284.6	)		0.0
Other assets		(0.2	)		4.5			4.9		2.3		0.0			11.5
Total assets	$	(18.5	)	$	1,084.5		$	772.3	$	444.9	$	(1,170.3	)	$	1,112.9
LIABILITIES AND EQUITY
Accounts payable	$	0.0		$	73.8		$	18.9	$	48.1	$	0.0		$	140.8
Affiliated payables		0.0			16.6			10.9		15.3		(42.8	)		0.0
Accrued liabilities		0.0			35.6			23.4		40.8		0.0			99.8
Current maturities of long-term debt		0.0			30.2			0.0		9.7		0.0			39.9
Total current liabilities		0.0			156.2			53.2		113.9		(42.8	)		280.5
Long-term debt		0.0			647.5			0.0		34.9		0.0			682.4
Affiliated debt		0.0			217.5			29.5		36.9		(283.9	)		0.0
Other long-term liabilities		0.0			81.6			13.2		67.6		0.0			162.4
Total liabilities		0.0			1,102.8			95.9		253.3		(326.7	)		1,125.3
Koppers shareholders’ equity		(18.5	)		(18.3	)		676.4		185.5		(843.6	)		(18.5	)
Noncontrolling interests		0.0			0.0			0.0		6.1		0.0			6.1
Total liabilities and equity	$	(18.5	)	$	1,084.5		$	772.3	$	444.9	$	(1,170.3	)	$	1,112.9

Condensed Consolidating Statement of Cash Flows

For the Year Ended December 31, 2016

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Cash provided by (used in) operating activities	$	(0.1	)	$	106.6		$	77.0		$	29.1		$	(93.1	)	$	119.5
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions		0.0			(30.1	)		(7.1	)		(12.7	)		0.0			(49.9	)
Repayments (loans to) from affiliates		0.0			(6.9	)		16.9			9.8			(19.8	)		0.0
Net cash proceeds (payments) from divestitures and asset sales		0.0			00.0			0.9			(4.7	)		00.0			(3.8	)
Net cash (used in) provided by investing activities		0.0			(37.0	)		10.7			(7.6	)		(19.8	)		(53.7	)
Cash provided by (used in) financing activities:
(Repayments) borrowings of long-term debt		0.0			(59.9	)		0.1			(1.6	)		0.0			(61.4	)
Borrowings (repayments) of affiliated debt		0.0			(7.2	)		(6.5	)		(6.1	)		19.8			00.0
Deferred financing costs		0.0			(1.4	)		0.0			0.0			0.0			(1.4	)
Dividends paid		(0.0	)		(1.2	)		(82.0	)		(9.9	)		93.1			(0.0	)
Stock repurchased		0.1			0.0			0.0			0.0			0.0			0.1
Net cash used in financing activities		0.1			(69.7	)		(88.4	)		(17.6	)		112.9			(62.7	)
Effect of exchange rates on cash		0.0			0.0			0.0			(4.1	)		0.0			(4.1	)
Net increase (decrease) in cash and cash equivalents		0.0			(0.1	)		(0.7	)		(0.2	)		0.0			(1.0	)
Cash and cash equivalents at beginning of year		0.0			0.1			0.7			21.0			0.0			21.8
Cash and cash equivalents at end of period	$	0.0		$	0.0		$	0.0		$	20.8		$	0.0		$	20.8

Condensed Consolidating Statement of Cash Flows

For the Year Ended December 31, 2015

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Cash provided by (used in) operating activities	$	5.4		$	63.0		$	55.9		$	60.3		$	(56.9	)	$	127.7
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions		0.0			(41.2	)		(5.3	)		(9.5	)		0.0			(56.0	)
(Loans to) repayments from affiliates		0.0			6.3			(5.1	)		9.2			(10.4	)		0.0
Net cash proceeds from divestitures and asset sales		0.0			12.3			2.1			0.5			0.0			14.9
Net cash (used in) provided by investing activities		0.0			(22.6	)		(8.3	)		0.2			(10.4	)		(41.1	)
Cash provided by (used in) financing activities:
Borrowings (repayments) of long-term debt		0.0			(104.2	)		0.1			(9.3	)		0.0			(113.4	)
Borrowings (repayments) of affiliated debt		0.0			71.0			(6.4	)		(75.0	)		10.4			0.0
Deferred financing costs		0.0			(1.0	)		0.0			0.0			0.0			(1.0	)
Dividends paid		(5.1	)		(6.2	)		(40.8	)		(13.5	)		56.9			(8.7	)
Stock (repurchased) issued		(0.3	)		0.0			0.0			0.0			0.0			(0.3	)
Net cash (used in) provided by financing activities		(5.4	)		(40.4	)		(47.1	)		(97.8	)		67.3			(123.4	)
Effect of exchange rates on cash		0.0			0.1			(0.7	)		8.1			0.0			7.5
Net (decrease) increase in cash and cash equivalents		0.0			0.1			(0.2	)		(29.2	)		0.0			(29.3	)
Cash and cash equivalents at beginning of year		0.0			0.0			0.9			50.2			0.0			51.1
Cash and cash equivalents at end of period	$	0.0		$	0.1		$	0.7		$	21.0		$	0.0		$	21.8

Condensed Consolidating Statement of Cash Flows

For the Year Ended December 31, 2014

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Cash provided by (used in) operating activities	$	21.8		$	23.8		$	33.8		$	10.4		$	(54.3	)	$	35.5
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions		0.0			(518.5	)		(16.7	)		(59.9	)		14.8			(580.3	)
(Loans to) repayments from affiliates		0.0			(32.2	)		(38.9	)		0.0			71.1			0.0
Net cash proceeds (payments) from divestitures and asset sales		0.0			0.1			0.1			0.1			0.0			0.3
Net cash used in investing activities		0.0			(550.6	)		(55.5	)		(59.8	)		85.9			(580.0	)
Cash provided by (used in) financing activities:
Repayments of long-term debt		0.0			497.0			0.0			50.5			0.0			547.5
Borrowings of affiliated long- term debt		0.0			35.8			27.6			7.7			(71.1	)		0.0
Deferred financing costs		0.0			(11.1	)		0.0			0.0			0.0			(11.1	)
Other financing receipts		0.0			0.0			0.0			1.4			0.0			1.4
Dividends paid		(20.5	)		(23.6	)		(6.1	)		(24.5	)		54.3			(20.4	)
Stock issued and repurchased		(1.3	)		0.0			0.0			14.8			(14.8	)		(1.3	)
Net cash provided by (used in) financing activities		(21.8	)		498.1			21.5			49.9			(31.6	)		516.1
Effect of exchange rates on cash		0.0			(1.2	)		1.0			(2.5	)		0.0			(2.7	)
Net increase in cash and cash equivalents		0.0			(29.9	)		0.8			(2.0	)		0.0			(31.1	)
Cash and cash equivalents at beginning of year		0.0			29.9			0.1			52.2			0.0			82.2
Cash and cash equivalents at end of period	$	0.0		$	0.0		$	0.9		$	50.2		$	0.0		$	51.1

Description of Business - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016 Segment
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of operating segments	3

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary Of Significant Accounting Policies [Line Items]
Foreign currency transaction (losses) gains									$ (1.3)	$ (10.4)	$ 0.6
Period for payment of approval basis sale									30 days
Net sales	$ 313.2	$ 371.1	$ 385.1	$ 346.8	$ 363.7	$ 433.8	$ 431.6	$ 397.8	$ 1,416.2	1,626.9	1,555.0
Research and development costs									$ 6.6	$ 5.2	3.4
Percentage of LIFO inventory	65.00%				66.00%				65.00%	66.00%
Inventory write-down									$ 0.6	$ 1.4	2.4
Advance payment received									$ 0.0	30.0
China [Member]
Summary Of Significant Accounting Policies [Line Items]
Advance payment received										30.0
Agreement period									50 years
Other Current Assets [Member]
Summary Of Significant Accounting Policies [Line Items]
Prepaid expenses	$ 17.0				$ 17.0				$ 17.0	17.0
Untreated Crosstie Sales [Member]
Summary Of Significant Accounting Policies [Line Items]
Net sales									$ 129.2	$ 129.8	$ 93.4
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Equity method investment significant influence percent									20.00%
Minimum [Member] \| Buildings [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives									10 years
Minimum [Member] \| Machinery and Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives									3 years
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Equity method investment significant influence percent									30.00%
Maximum [Member] \| Buildings [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives									20 years
Maximum [Member] \| Machinery and Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives									15 years

Summary of Significant Accounting Policies - Summary of Self-lnsured Liabilities (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Self-insured liabilities at beginning of year	$ 8.0	$ 8.2
Expense	5.1	2.6
Reserves recoverable from insurance	2.4	0.0
Reversal of self-insured liabilities	(1.7)	(1.0)
Cash expenditures	(2.9)	(1.8)
Self-insured liabilities at end of year	$ 10.9	$ 8.0

Summary of Significant Accounting Policies - Summary of Asset Retirement Obligation Liabilities (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Asset Retirement Obligation Disclosure [Abstract]
Asset retirement obligation at beginning of year	$ 46.5	$ 30.5
(Divestiture) acquisition	(8.0)	0.7
Accretion expense	7.1	3.7
Revision in estimated cash flows (a)	2.7	24.4
Cash expenditures	(11.4)	(12.1)
Currency translation	(0.9)	(0.7)
Balance at end of period	$ 36.0	$ 46.5

Summary of Significant Accounting Policies - Summary of Asset Retirement Obligation Liabilities (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Charges related to restructuring activities	$ 2.7	$ 23.4

Summary of Significant Accounting Policies - Summary of Changes to Deferred Revenue (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Deferred Revenue Disclosure [Abstract]
Deferred revenue at beginning of year	$ 30.1	$ 2.5
Advance payment	0.0	30.0
Revenue earned	(0.8)	(1.0)
Currency translation	(2.1)	(1.4)
Deferred revenue at end of year	$ 27.2	$ 30.1

New Accounting Pronouncements - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Adjustments for New Accounting Pronouncement [Member]
Summary Of Significant Accounting Policies [Line Items]
Debt issuance cost being reclassified from other assets to long-term debt	$ 12.5	$ 14.6

Plant Closures and Discontinued Operations - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2016	Mar. 31, 2016
Restructuring Cost and Reserve [Line Items]
Inventory write-down		$ 0.6	$ 1.4	$ 2.4
Asset retirement obligation charges		36.0	46.5	30.5
Gain (loss) on sale of business		2.1	3.2	$ 0.0
Real estate lease obligations					$ 3.7
North American Utility Pole Business [Member]
Restructuring Cost and Reserve [Line Items]
Gain (loss) on sale of business			3.2
Discontinued Operations Disposed Of By Means Other Than Sale [Member] \| China [Member] \| Koppers Carbon and Chemical Company Limited [Member]
Restructuring Cost and Reserve [Line Items]
Percentage of operations in Tangshan, China owned by the company						60.00%
Severance Charge			0.9
Inventory write-down		0.7
Discontinued Operations Disposed Of By Means Other Than Sale [Member] \| Pennsylvania [Member] \| Carbon Materials and Chemicals [Member]
Restructuring Cost and Reserve [Line Items]
Fixed asset subject to impairment		6.4
Severance, Inventory write-down, asset retirement obligation and fixed asset impairment charges			18.8
Plant closure costs		6.4
Discontinued Operations Disposed Of By Means Other Than Sale [Member] \| West Virginia [Member] \| Railroad and Utility Products and Services [Member]
Restructuring Cost and Reserve [Line Items]
Plant closure costs		3.0
Severance, asset retirement obligation and fixed asset impairment charges			5.7
Discontinued Operations, Disposed of by Sale [Member] \| United Kingdom [Member]
Restructuring Cost and Reserve [Line Items]
Severance Charge		1.5
Environmental charges			13.9
Asset retirement obligation charges			13.9
Fixed asset subject to impairment			13.9
Gain (loss) on sale of business		2.1
Discontinued Operations, Disposed of by Sale [Member] \| North American Utility Pole Business [Member]
Restructuring Cost and Reserve [Line Items]
Gain (loss) on sale of business	$ 3.2
Plant closure costs		2.7
Net cash proceeds from divestitures and asset sales	12.3
Promissory note received	$ 1.6
Long-term lease [Member] \| Wood Protection L.P [Member]
Restructuring Cost and Reserve [Line Items]
Revenues		$ 8.0	$ 14.0

Plant Closures and Discontinued Operations - Summary of Restructuring Activities and Related Reserves (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Reserve, Beginning Balance	$ 28.2	$ 8.1
Accrual	13.7	27.5
Costs charged against assets	(1.9)	(1.3)
Reversal of accrued charges	(11.2)	(0.3)
Cash paid	(11.7)	(5.1)
Currency translation	(1.0)	(0.7)
Reserve, Ending Balance	16.1	28.2
Severance and Employee Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Reserve, Beginning Balance	2.0	0.0
Accrual	2.4	2.2
Costs charged against assets	0.0	0.0
Reversal of accrued charges	(1.9)	0.0
Cash paid	(1.0)	(0.2)
Currency translation	(0.1)	0.0
Reserve, Ending Balance	1.4	2.0
Environmental Remediation [Member]
Restructuring Cost and Reserve [Line Items]
Reserve, Beginning Balance	4.3	4.1
Accrual	0.1	0.6
Costs charged against assets	0.0	0.0
Reversal of accrued charges	(0.5)	0.0
Cash paid	(2.4)	0.0
Currency translation	0.0	(0.4)
Reserve, Ending Balance	1.5	4.3
Asset Retirement [Member]
Restructuring Cost and Reserve [Line Items]
Reserve, Beginning Balance	21.9	3.9
Accrual	5.6	23.4
Costs charged against assets	0.0	0.0
Reversal of accrued charges	(8.7)	(0.3)
Cash paid	(8.1)	(4.8)
Currency translation	(0.7)	(0.3)
Reserve, Ending Balance	10.0	21.9
Other [Member]
Restructuring Cost and Reserve [Line Items]
Reserve, Beginning Balance	0.0	0.1
Accrual	5.6	1.3
Costs charged against assets	(1.9)	(1.3)
Reversal of accrued charges	(0.1)	0.0
Cash paid	(0.2)	(0.1)
Currency translation	(0.2)	0.0
Reserve, Ending Balance	$ 3.2	$ 0.0

Related Party Transactions - Additional Information (Detail) $ in Millions	1 Months Ended		12 Months Ended
	Feb. 28, 2017 USD ($)	Jan. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) Installment	Dec. 31, 2015 USD ($)
Related Party Transaction [Line Items]
Loan to related party			$ 8.9	$ 9.5
Tangshan Koppers Kailuan Carbon Chemical Company Limited [Member]
Related Party Transaction [Line Items]
Loan to related party			$ 9.5
Ownership percentage			30.00%
Equity loss recognized from related party			$ 1.1
Interest receivable			$ 0.5
Number of installment payments \| Installment			2
Loan installments expected to received by end date			Jun. 30, 2017
Tangshan Koppers Kailuan Carbon Chemical Company Limited [Member] \| Loan [Member] \| Scenario, Forecast [Member]
Related Party Transaction [Line Items]
Installment payments	$ 5.2
Tangshan Koppers Kailuan Carbon Chemical Company Limited [Member] \| Loan [Member] \| Subsequent Event [Member]
Related Party Transaction [Line Items]
Installment payments		$ 5.2

Fair Value Measurements - Schedule of Company's Financial Instruments (Detail) - USD ($)
$ in Millions

Dec. 31, 2016

Dec. 31, 2015

Fair Value [Member]

Financial assets:

Cash and cash equivalents, including restricted cash

$ 20.8

$ 21.8

Investments and other assets

^[1]

1.1

Financial liabilities:

Long-term debt (including current portion)

669.6

724.6

Carrying Value [Member]

Financial assets:

Cash and cash equivalents, including restricted cash

20.8

21.8

Investments and other assets

^[1]

1.1

Financial liabilities:

Long-term debt (including current portion)

$ 662.4

$ 722.3

[1]	Excludes equity method investments.

Earnings per Common Share - Schedule of Computation of Basic and Diluted Earnings per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Net income (loss) attributable to Koppers	$ 6.4	$ 12.1	$ 12.1	$ (1.3)	$ (87.7)	$ 10.1	$ 9.0	$ (3.4)	$ 29.3	$ (72.0)	$ (32.4)
Less: Income (loss) from discontinued operations									0.6	(0.1)	0.6
Income (loss) from continuing operations attributable to Koppers									$ 28.7	$ (71.9)	$ (33.0)
Weighted average common shares outstanding:
Basic									20,636	20,541	20,463
Effect of dilutive securities									419	0	0
Diluted									21,055	20,541	20,463
Earnings (loss) per common share – continuing operations:
Basic earnings (loss) per common share	$ 0.31	$ 0.59	$ 0.58	$ (0.09)	$ (4.27)	$ 0.49	$ 0.44	$ (0.16)	$ 1.39	$ (3.50)	$ (1.61)
Diluted earnings (loss) per common share	$ 0.30	$ 0.58	$ 0.57	$ (0.09)	$ (4.27)	$ 0.49	$ 0.44	$ (0.16)	$ 1.36	$ (3.50)	$ (1.61)
Other data:
Antidilutive securities excluded from computation of diluted earnings per common share									415	688	362

Stock-based Compensation - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future compensation expense related to non-vested stock-based compensation arrangements	$ 12.0
Future compensation expense, weighted-average expected period of recognition in months	25 months
Restricted Stock Units (RSUs) [Member] \| Board of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards, vesting period	1 year
Restricted Stock Units (RSUs) [Member] \| March 2015 and 2016 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards, vesting period	4 years
Performance Stock Units [Member] \| March 2015 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards, vesting period		3 years
Percentage of target award earned by participants		200.00%
Vesting performance stock units if minimum performance criteria are not achieved		0
Stock options, term in years		3 years
Performance Stock Units [Member] \| March 2015 Grant [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target award earned by participants		0.00%
Performance Stock Units [Member] \| March 2015 Grant [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target award earned by participants		150.00%
Performance Stock Units [Member] \| March 2016 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards, vesting period	3 years
Vesting performance stock units if minimum performance criteria are not achieved	0
Stock options, term in years	3 years
Performance Stock Units [Member] \| March 2016 Grant [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target award earned by participants	0.00%
Performance Stock Units [Member] \| March 2016 Grant [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target award earned by participants	200.00%
Employee Stock Option [Member] \| March 2015 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, term in years	10 years
Employee Stock Option [Member] \| Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards, vesting period	4 years
Employee Stock Option [Member] \| Executive Officer \| March 2015 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards, vesting period	3 years

Stock-based Compensation - Performance Award Fair Value Assumptions (Detail) - March 2016 Grant [Member]	12 Months Ended
	Dec. 31, 2016 $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share	$ 18.11
Expected dividend yield per share	0.00%
Expected volatility	40.86%
Risk-free interest rate	1.45%
Grant date fair value per share	$ 7.41
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share	$ 18.11
Expected dividend yield per share	0.00%
Expected volatility	40.86%
Risk-free interest rate	0.96%
Look-back period in years	2 years 10 months 2 days
Grant date fair value per share	$ 23.70

Stock-based Compensation - Summary of Performance Stock Units (Detail) - shares	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	834,195	610,607
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	554,388	397,399
2014 - 2016 [Member] \| Performance Stock Units, Target Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	87,262
2015 - 2017 [Member] \| Performance Stock Units, Target Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	203,953
2016 - 2018 [Member] \| Performance Stock Units, Target Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	260,588
Minimum [Member] \| 2014 - 2016 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	0
Minimum [Member] \| 2015 - 2017 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	0
Minimum [Member] \| 2016 - 2018 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	0
Maximum [Member] \| 2014 - 2016 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	130,893
Maximum [Member] \| 2015 - 2017 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	407,906
Maximum [Member] \| 2016 - 2018 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	521,176

Stock-based Compensation - Summary of Status and Activity of Non-Vested Stock Awards (Detail)	12 Months Ended
	Dec. 31, 2016 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested, Beginning Balance	610,607
Granted	443,263
Credited from dividends	2,662
Vested	(100,281)
Forfeited	(122,056)
Non-vested, Ending Balance	834,195
Beginning Balance, Non-vested, Weighted Average Grant Date Fair Value per Unit \| $ / shares	$ 27.29
Granted, Weighted Average Grant Date Fair Value per Unit \| $ / shares	22.25
Credited from dividends, Weighted Average Grant Date Fair Value per Unit \| $ / shares	25.47
Vested, Weighted Average Grant Date Fair Value per Unit \| $ / shares	28.77
Forfeited, Weighted Average Grant Date Fair Value per Unit \| $ / shares	36.46
Ending Balance, Non-vested, Weighted Average Grant Date Fair Value per Unit \| $ / shares	$ 23.09
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested, Beginning Balance	213,208
Granted	178,282
Credited from dividends	950
Vested	(100,281)
Forfeited	(12,352)
Non-vested, Ending Balance	279,807
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested, Beginning Balance	397,399
Granted	264,981
Credited from dividends	1,712
Vested	0
Forfeited	(109,704)
Non-vested, Ending Balance	554,388

Stock-based Compensation - Stock Options Fair Value Assumptions (Detail)	12 Months Ended
	Dec. 31, 2016 $ / shares
March 2016 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share	$ 18.11
Expected dividend yield per share	0.00%
Expected life in years	5 years 11 months 16 days
Expected volatility	40.86%
Risk-free interest rate	1.45%
Grant date fair value per share	$ 7.41
March 2015 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share	$ 17.57
Expected dividend yield per share	3.40%
Expected life in years	5 years 9 months
Expected volatility	42.27%
Risk-free interest rate	1.73%
Grant date fair value per share	$ 5.20
February 2014 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share	$ 37.93
Expected dividend yield per share	2.75%
Expected life in years	6 years 6 months
Expected volatility	52.14%
Risk-free interest rate	1.98%
Grant date fair value per share	$ 15.26

Stock-based Compensation - Summary of Status and Activity of Stock Options (Detail) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options, Outstanding at December 31, 2015 \| shares	774,249
Options, Granted \| shares	211,193
Options, Exercised \| shares	(15,901)
Options, Expired \| shares	(14,548)
Options, Forfeited \| shares	(19,539)
Options, Outstanding at December 31, 2016 \| shares	935,454
Options, Exercisable at December 31, 2016 \| shares	436,582
Weighted Average Exercise Price per Option, Outstanding at December 31, 2015 \| $ / shares	$ 28.46
Weighted Average Exercise Price per Option, Granted \| $ / shares	18.11
Weighted Average Exercise Price per Option, Exercised \| $ / shares	24.94
Weighted Average Exercise Price per Option, Expired \| $ / shares	40.38
Weighted Average Exercise Price per Option, Forfeited \| $ / shares	23.70
Weighted Average Exercise Price per Option, Outstanding at December 31, 2016 \| $ / shares	26.10
Weighted Average Exercise Price per Option, Exercisable at December 31, 2016 \| $ / shares	$ 33.07
Weighted Average Remaining Contractual Term, Outstanding at December 31, 2016	6 years 5 months 16 days
Weighted Average Remaining Contractual Term, Exercisable at December 31, 2016	4 years 1 month 21 days
Aggregate Intrinsic Value, Outstanding at December 31, 2016 \| $	$ 6.0
Aggregate Intrinsic Value, Exercisable at December 31, 2016 \| $	$ 3.3

Stock-based Compensation - Schedule of Stock-Based Compensation Expense Recognized (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock-based compensation expense recognized:
Less related income tax benefit	$ 3.6	$ 1.5	$ 1.9
Decrease in net income attributable to Koppers	5.3	2.3	2.8
Intrinsic value of exercised stock options	0.1	0.0	0.3
Cash received from the exercise of stock options	0.4	0.0	0.7
Selling, General and Administrative Expenses [Member]
Stock-based compensation expense recognized:
Stock-based compensation expense	$ 8.9	$ 3.8	$ 4.7

Segment Information - Additional Information (Detail) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) Segment	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments \| Segment									3
Net sales	$ 313.2	$ 371.1	$ 385.1	$ 346.8	$ 363.7	$ 433.8	$ 431.6	$ 397.8	$ 1,416.2	$ 1,626.9	$ 1,555.0
Non-U.S. Countries [Member]
Segment Reporting Information [Line Items]
Net sales									$ 486.9	$ 635.7	$ 722.0

Segment Information - Summary of Results of Segment Operations (Detail) - USD ($)
$ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2016

Sep. 30, 2016

Jun. 30, 2016

Mar. 31, 2016

Dec. 31, 2015

Sep. 30, 2015

Jun. 30, 2015

Mar. 31, 2015

Dec. 31, 2016

Dec. 31, 2015

Dec. 31, 2014

Revenues from external customers:

Net sales

$ 313.2

$ 371.1

$ 385.1

$ 346.8

$ 363.7

$ 433.8

$ 431.6

$ 397.8

$ 1,416.2

$ 1,626.9

$ 1,555.0

Depreciation and amortization expense

52.9

59.0

44.0

Operating profit (loss)

$ 18.9

$ 27.7

$ 32.0

$ 7.8

$ (90.6)

$ 27.0

$ 26.0

$ 8.0

86.4

(29.6)

33.2

Capital expenditures (including acquisitions)

49.9

56.0

580.0

Railroad and Utility Products and Services [Member]

Revenues from external customers:

Net sales

586.5

657.0

597.8

Carbon Materials and Chemicals [Member]

Revenues from external customers:

Net sales

436.3

613.4

833.7

Performance Chemicals [Member]

Revenues from external customers:

Net sales

393.4

356.5

123.5

Operating Segments [Member] | Railroad and Utility Products and Services [Member]

Revenues from external customers:

Net sales

586.5

657.0

597.8

Depreciation and amortization expense

^[1]

13.0

14.2

11.9

Operating profit (loss)

^[2]

51.1

62.2

53.6

Capital expenditures (including acquisitions)

11.2

11.1

44.5

Operating Segments [Member] | Carbon Materials and Chemicals [Member]

Revenues from external customers:

Net sales

436.3

613.4

833.7

Depreciation and amortization expense

^[3]

21.2

25.8

25.0

Operating profit (loss)

^[4]

(25.1)

(125.0)

(5.3)

Capital expenditures (including acquisitions)

29.5

37.6

63.7

Operating Segments [Member] | Performance Chemicals [Member]

Revenues from external customers:

Net sales

393.4

356.5

123.5

Depreciation and amortization expense

18.7

19.0

7.1

Operating profit (loss)

62.0

39.0

1.6

Capital expenditures (including acquisitions)

7.9

5.8

471.1

Intersegment [Member]

Revenues from external customers:

Net sales

98.3

95.4

87.8

Intersegment [Member] | Carbon Materials and Chemicals [Member]

Revenues from external customers:

Net sales

90.2

86.7

84.8

Intersegment [Member] | Performance Chemicals [Member]

Revenues from external customers:

Net sales

8.1

8.7

3.0

Corporate, Non-Segment [Member]

Revenues from external customers:

Operating profit (loss)

^[5]

(1.6)

(5.8)

(16.7)

Capital expenditures (including acquisitions)

$ 1.3

$ 1.5

$ 0.7

[1]	Excludes impairment charges of $1.9 million in 2015 for a wood treating facility in the United States.
[2]	Includes asset retirement obligation and other restructuring costs of $6.9 million for the restructuring of three facilities in the United States in 2016. Includes gain on sale of the Company’s North American utility pole business of $3.2 million and restructuring costs of $5.7 million for a wood treating facility in the United States in 2015.
[3]	Excludes impairment charges of $3.5, $12.8 and $4.7 million in 2016, 2015 and 2014, respectively, for CMC.
[4]	Includes plant closure costs of $13.2, $36.5 and $18.1 million in 2016, 2015 and 2014, respectively, for CMC. In the fourth quarter of 2015, the Company also recorded goodwill impairment charges of $67.2 million related to this business unit.
[5]	Operating loss for Corporate includes general and administrative costs for Koppers Holdings Inc., the parent company of Koppers Inc., foreign exchange revaluation related to intercompany loans in connection with a legal reorganization of the Company and acquisition and acquisition-related integration costs.

Segment Information - Summary of Results of Segment Operations (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue from External Customer [Line Items]
Impairment charges	$ 35.1	$ 3.5	$ 14.7	$ 4.7
Gain (loss) on sale of business		2.1	3.2	0.0
Charges related to restructuring activities		2.7	23.4
Goodwill impairment charge	67.2	0.0	67.2	0.0
United States [Member]
Revenue from External Customer [Line Items]
Asset retirement obligation and other restructuring costs		6.9
Wood Treating Facility [Member] \| United States [Member]
Revenue from External Customer [Line Items]
Impairment charges			1.9
North American Utility Pole Business [Member]
Revenue from External Customer [Line Items]
Gain (loss) on sale of business			3.2
North American Utility Pole Business [Member] \| Wood Treating Facility [Member] \| United States [Member]
Revenue from External Customer [Line Items]
Charges related to restructuring activities			5.7
Carbon Materials and Chemicals [Member]
Revenue from External Customer [Line Items]
Impairment charges		3.5	12.8	4.7
Plant closure cost		$ 13.2	36.5	$ 18.1
Goodwill impairment charge	$ 67.2		$ 67.2

Segment Information - Summary of Tangible and Intangible Assets by Segments (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Asset Reconciling Item [Line Items]
Assets	$ 1,087.5	$ 1,112.9
Cash and cash equivalents	20.8	21.8	$ 51.1	$ 82.2
Income tax receivable	3.8	4.6
Deferred taxes	69.1	70.3
Property, plant and equipment, net	280.8	277.8
Goodwill	186.4	186.6	247.2
Operating Segments [Member]
Segment Reporting Asset Reconciling Item [Line Items]
Assets	1,040.1	1,063.8
Corporate, Non-Segment [Member]
Segment Reporting Asset Reconciling Item [Line Items]
Cash and cash equivalents	0.0	0.1
Income tax receivable	3.8	4.6
Deferred taxes	32.5	32.6
Property, plant and equipment, net	4.9	4.7
Deferred charges	0.7	1.6
Other	5.5	5.4
Railroad and Utility Products and Services [Member]
Segment Reporting Asset Reconciling Item [Line Items]
Goodwill	9.9	9.9	9.3
Railroad and Utility Products and Services [Member] \| Operating Segments [Member]
Segment Reporting Asset Reconciling Item [Line Items]
Assets	264.2	254.1
Goodwill	9.9	9.9
Carbon Materials and Chemicals [Member]
Segment Reporting Asset Reconciling Item [Line Items]
Goodwill	0.0	0.0	65.5
Carbon Materials and Chemicals [Member] \| Operating Segments [Member]
Segment Reporting Asset Reconciling Item [Line Items]
Assets	333.0	368.4
Performance Chemicals [Member]
Segment Reporting Asset Reconciling Item [Line Items]
Goodwill	176.5	176.7	$ 172.4
Performance Chemicals [Member] \| Operating Segments [Member]
Segment Reporting Asset Reconciling Item [Line Items]
Assets	442.9	441.3
Goodwill	$ 176.5	$ 176.7

Segment Information - Schedule of Revenues and Long-Lived Assets by Geographic Area (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenues from external customers	$ 313.2	$ 371.1	$ 385.1	$ 346.8	$ 363.7	$ 433.8	$ 431.6	$ 397.8	$ 1,416.2	$ 1,626.9	$ 1,555.0
Long-lived assets	622.3				644.5				622.3	644.5	744.9
United States [Member]
Segment Reporting Information [Line Items]
Revenues from external customers									929.3	991.2	833.0
Long-lived assets	446.6				460.3				446.6	460.3	518.8
Australia [Member]
Segment Reporting Information [Line Items]
Revenues from external customers									228.4	280.9	349.0
Long-lived assets	124.3				132.9				124.3	132.9	160.3
Europe [Member]
Segment Reporting Information [Line Items]
Revenues from external customers									140.2	144.0	201.1
Long-lived assets	31.9				32.9				31.9	32.9	47.5
Other Countries [Member]
Segment Reporting Information [Line Items]
Revenues from external customers									118.3	210.8	171.9
Long-lived assets	$ 19.5				$ 18.3				$ 19.5	$ 18.3	$ 18.3

Segment Information - Schedule of Segment Revenues for Significant Product Lines (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Net sales	$ 313.2	$ 371.1	$ 385.1	$ 346.8	$ 363.7	$ 433.8	$ 431.6	$ 397.8	$ 1,416.2	$ 1,626.9	$ 1,555.0
Railroad and Utility Products and Services [Member]
Segment Reporting Information [Line Items]
Net sales									586.5	657.0	597.8
Railroad and Utility Products and Services [Member] \| Railroad Crossties [Member]
Segment Reporting Information [Line Items]
Net sales									374.0	422.0	371.4
Railroad and Utility Products and Services [Member] \| Utility Poles [Member]
Segment Reporting Information [Line Items]
Net sales									34.5	52.4	96.1
Railroad and Utility Products and Services [Member] \| Creosote [Member]
Segment Reporting Information [Line Items]
Net sales									49.6	45.7	51.2
Railroad and Utility Products and Services [Member] \| Rail Joints [Member]
Segment Reporting Information [Line Items]
Net sales									24.4	28.1	27.2
Railroad and Utility Products and Services [Member] \| Railroad Infrastructure Services [Member]
Segment Reporting Information [Line Items]
Net sales									43.4	42.7	14.8
Railroad and Utility Products and Services [Member] \| Other Products [Member]
Segment Reporting Information [Line Items]
Net sales									60.6	66.1	37.1
Carbon Materials and Chemicals [Member]
Segment Reporting Information [Line Items]
Net sales									436.3	613.4	833.7
Carbon Materials and Chemicals [Member] \| Other Products [Member]
Segment Reporting Information [Line Items]
Net sales									98.4	145.3	198.4
Carbon Materials and Chemicals [Member] \| Carbon Pitch [Member]
Segment Reporting Information [Line Items]
Net sales									191.0	283.4	330.2
Carbon Materials and Chemicals [Member] \| Creosote and Carbon Black Feedstock [Member]
Segment Reporting Information [Line Items]
Net sales									71.3	119.6	213.7
Carbon Materials and Chemicals [Member] \| Phthalic Anhydride [Member]
Segment Reporting Information [Line Items]
Net sales									75.6	65.1	91.4
Performance Chemicals [Member]
Segment Reporting Information [Line Items]
Net sales									393.4	356.5	123.5
Performance Chemicals [Member] \| Other Products [Member]
Segment Reporting Information [Line Items]
Net sales									27.9	37.9	16.5
Performance Chemicals [Member] \| Wood Preservative Products [Member]
Segment Reporting Information [Line Items]
Net sales									$ 365.5	$ 318.6	$ 107.0

Income Taxes - Summary of Income Tax Provision (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal	$ (1.9)	$ (4.2)	$ 17.5
State	1.3	0.2	0.3
Foreign	13.3	16.0	14.6
Total current tax provision	12.7	12.0	32.4
Deferred:
Federal	(1.6)	(19.2)	3.1
State	0.5	3.0	0.0
Foreign	(0.2)	0.0	(1.4)
Total deferred tax (benefit) provision	(1.3)	(16.2)	1.7
Total income tax (benefit) provision	$ 11.4	$ (4.2)	$ 34.1

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Line Items]
Income (loss) before income taxes		$ 48.2	$ (15.2)	$ (1.5)
Unremitted earnings		85.0
Taxable amount of unremitted earnings		85.0
Income tax expense (benefit) relating to copper swap contracts		8.0	(1.2)	(2.6)
Income tax expense (benefit) relating to unfunded status of employee post-retirement benefit plans		2.0	0.6	(8.1)
Income tax expense related to restricted stock and stock options		0.4	0.5	0.3
Valuation allowance	$ 41.9	40.2	41.9
Goodwill impairment	67.2	$ 0.0	67.2	0.0
Goodwill impairment charge, not deductible during the period			25.1
Goodwill impairment charge, not deductible cumulative period		3 years
Interest expense (income) and related penalties		$ 1.2	(1.5)	$ 1.5
Accrued interest expense and penalties	1.2	4.2	1.2
Unrecognized tax benefits		3.0
Unrecognized tax benefits with impact on the effective tax rate	$ 4.1	5.7	$ 4.1
Valuation Allowance Operating Loss Carryforwards [Member]
Income Taxes [Line Items]
Valuation allowance		1.6
U.K. [Member]
Income Taxes [Line Items]
Valuation allowance		$ 2.1

Income Taxes - Summary of Income Taxes Reconciled with Federal Statutory Rate (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Federal income tax rate	35.00%	35.00%	35.00%
State income taxes, net of federal tax benefit	(0.80%)	2.30%	(4.80%)
Foreign earnings taxed at different rates	(10.10%)	(8.30%)	(347.60%)
Domestic production activities deduction	0.00%	(0.60%)	40.80%
Deferred tax adjustments	(0.20%)	0.40%	3.20%
Change in tax contingency reserves	6.50%	1.50%	(15.20%)
Legal entity tax restructuring project	(0.00%)	(0.00%)	(1503.20%)
Foreign tax credits	(0.00%)	(0.00%)	1203.40%
Changes to foreign repatriation plans	0.00%	0.00%	104.00%
Valuation allowance charges	(1.90%)	(13.00%)	(92.40%)
Goodwill impairment	0.00%	(10.90%)	0.00%
Other	1.10%	(1.10%)	(1.20%)
Total effective tax rate	29.60%	5.30%	(578.00%)

Income Taxes - Summary of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Reserves, including insurance, environmental and deferred revenue	$ 22.3	$ 19.9
Pension and other postretirement benefits obligations	19.2	19.4
Tax credits	15.4	16.8
Asset retirement obligations	12.0	12.0
State tax losses carryforwards (expiring from 2017-2036)	11.3	10.2
Foreign tax loss carryforwards (expiring beginning in 2018)	10.1	9.3
Accrued employee compensation	8.9	6.9
Book/tax inventory accounting differences	3.5	3.2
Capital loss benefit	0.0	0.9
Book over tax depreciation and amortization	0.0	3.6
Other	6.6	10.0
Valuation allowance	(40.2)	(41.9)
Total deferred tax assets	69.1	70.3
Deferred tax liabilities:
Tax over book depreciation and amortization	42.7	38.4
Gain on derivative contracts	4.2	0.0
Tax/book inventory accounting differences	0.0	0.3
Other	1.4	0.7
Total deferred tax liabilities	48.3	39.4
Net deferred tax assets	$ 20.8	$ 30.9

Income Taxes - Summary of Deferred Tax Assets and Liabilities (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2016
State [Member] \| Minimum [Member]
Income Taxes [Line Items]
Deferred tax assets, operating loss carryforwards, expiration date	2017
State [Member] \| Maximum [Member]
Income Taxes [Line Items]
Deferred tax assets, operating loss carryforwards, expiration date	2036
Foreign [Member]
Income Taxes [Line Items]
Deferred tax assets, operating loss carryforwards, expiration date	2018

Income Taxes - Summary of Valuation Allowances Recorded to Offset Deferred Tax Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
Total valuation allowances	$ 40.2	$ 41.9
Foreign [Member] \| Tax Credits [Member]
Income Taxes [Line Items]
Total valuation allowances	14.3	14.9
Foreign [Member] \| Operating Losses and Capital Losses [Member]
Income Taxes [Line Items]
Total valuation allowances	12.7	15.4
State [Member] \| Operating Losses and Tax Credits [Member]
Income Taxes [Line Items]
Total valuation allowances	$ 13.2	$ 11.6

Income taxes - Summary of Unrecognized Tax Benefits (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 7.7	$ 7.2	$ 6.1
Additions based on tax provisions related to the current year	0.9	1.4	0.6
Additions for tax provisions of prior years	1.5	0.0	0.1
Additions as a result of acquisitions	0.0	0.0	1.6
Reductions of tax provisions of prior years	0.0	(0.7)	(0.6)
Reductions as a result of a lapse of the applicable statute of limitations	(0.4)	(0.2)	(0.6)
Balance at end of year	$ 9.7	$ 7.7	$ 7.2

Inventories - Components of Inventories (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Raw materials	$ 157.7	$ 169.8
Work in process	14.2	15.5
Finished goods	103.6	97.4
Inventories, gross	275.5	282.7
Less revaluation to LIFO	46.8	56.3
Net	$ 228.7	$ 226.4

Equity Investments - Additional Information (Detail) - USD ($)	12 Months Ended		36 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Dividends received from equity method investment			$ 0
KSA Limited Partnership [Member]
Schedule of Equity Method Investments [Line Items]
Sale of assets of equity method investment		$ 2,500,000
Gain on sale of equity method investments		$ 300,000
Ownership percentage	50.00%		50.00%
Tangshan Koppers Kailuan Carbon Chemical Company Limited [Member]
Schedule of Equity Method Investments [Line Items]
Gain on sale of equity method investments	$ 1,100,000
Ownership percentage	30.00%		30.00%

Equity Investments - Equity Losses and Dividends Received (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Equity Method Investments And Joint Ventures [Abstract]
Equity loss	$ (1.0)	$ (2.2)	$ (1.6)

Property, Plant and Equipment - Property, Plant and Equipment (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 791.2	$ 748.4
Less accumulated depreciation	510.4	470.6
Net	280.8	277.8
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	17.0	17.6
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	58.2	61.8
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 716.0	$ 669.0

Property, Plant and Equipment - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Depreciation, including impairment charges		$ 41.6	$ 58.4	$ 38.8
Impairment charges	$ 35.1	3.5	14.7	4.7
Carbon Materials and Chemicals [Member]
Property, Plant and Equipment [Line Items]
Impairment charges		3.5	12.8	4.7
Carbon Materials and Chemicals [Member] \| China [Member]
Property, Plant and Equipment [Line Items]
Impairment charges				4.7
Carbon Materials and Chemicals [Member] \| China [Member] \| Koppers Shareholder's Equity (Deficit) [Member]
Property, Plant and Equipment [Line Items]
Impairment charges				$ 2.8
Carbon Materials and Chemicals [Member] \| Coal Tar Distillation Plant [Member]
Property, Plant and Equipment [Line Items]
Impairment charges		$ 3.5	$ 14.7

Goodwill and Other Identifiable Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Acquired Finite-Lived Intangible Assets [Line Items]
Balance beginning		$ 186.6	$ 247.2
Acquisitions			4.1
Purchase price allocation adjustments			9.5
Impairment	$ (67.2)	0.0	(67.2)	$ 0.0
Currency translation		(0.2)	(7.0)
Balance ending	186.6	186.4	186.6	247.2
Carbon Materials and Chemicals [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Balance beginning		0.0	65.5
Acquisitions			4.1
Purchase price allocation adjustments			0.0
Impairment	(67.2)		(67.2)
Currency translation		0.0	(2.4)
Balance ending	0.0	0.0	0.0	65.5
Railroad and Utility Products and Services [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Balance beginning		9.9	9.3
Acquisitions			0.0
Purchase price allocation adjustments			1.2
Impairment			0.0
Currency translation		0.0	(0.6)
Balance ending	9.9	9.9	9.9	9.3
Performance Chemicals [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Balance beginning		176.7	172.4
Acquisitions			0.0
Purchase price allocation adjustments			8.3
Impairment			0.0
Currency translation		(0.2)	(4.0)
Balance ending	$ 176.7	$ 176.5	$ 176.7	$ 172.4

Goodwill and Other Identifiable Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill And Other Intangible Assets [Line Items]
Goodwill impairment charge	$ 67,200,000	$ 0	$ 67,200,000	$ 0
Goodwill	186,600,000	186,400,000	186,600,000	247,200,000
Accumulated impairment losses	67,200,000	67,200,000	67,200,000
Amortization expense		14,800,000	15,300,000	8,400,000
Foreign Currency Translation [Member]
Goodwill And Other Intangible Assets [Line Items]
Decrease in carrying value of identifiable intangible assets		500,000
Carbon Materials and Chemicals [Member]
Goodwill And Other Intangible Assets [Line Items]
Goodwill impairment charge	67,200,000		67,200,000
Fair value of goodwill	0		0
Goodwill	$ 0	$ 0	$ 0	$ 65,500,000

Goodwill and Other Identifiable Intangible Assets - Schedule of Identifiable Intangible Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average remaining life in years	11 years 10 months 24 days
Gross Carrying Amount	$ 189.4	$ 189.9
Accumulated Amortization	47.5	33.8
Net	$ 141.9	156.1
Customer Contracts [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average remaining life in years	13 years 2 months 12 days
Gross Carrying Amount	$ 152.5	153.0
Accumulated Amortization	33.6	24.3
Net	$ 118.9	128.7
Customer Contracts [Member] \| Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	9 years
Customer Contracts [Member] \| Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	18 years
Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average remaining life in years	5 years
Gross Carrying Amount	$ 26.7	26.6
Accumulated Amortization	8.8	5.1
Net	$ 17.9	21.5
Technology [Member] \| Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	4 years
Technology [Member] \| Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	12 years
Trademarks [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average remaining life in years	4 years 7 months 6 days
Gross Carrying Amount	$ 6.1	5.9
Accumulated Amortization	1.9	1.1
Net	$ 4.2	4.8
Trademarks [Member] \| Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	4 years
Trademarks [Member] \| Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	7 years
Supply Contracts [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	10 years
Weighted average remaining life in years	3 years 2 months 12 days
Gross Carrying Amount	$ 2.2	2.3
Accumulated Amortization	1.5	1.4
Net	$ 0.7	0.9
Non-Compete Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	12 years
Weighted average remaining life in years	7 years 9 months 18 days
Gross Carrying Amount	$ 1.3	1.4
Accumulated Amortization	1.1	1.2
Net	$ 0.2	0.2
Favorable Lease Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	3 years
Weighted average remaining life in years	0 years
Gross Carrying Amount	$ 0.6	0.7
Accumulated Amortization	0.6	0.7
Net	$ 0.0	$ 0.0

Goodwill and Other Identifiable Intangible Assets - Schedule of Future Amortization Expense (Detail) $ in Millions	Dec. 31, 2016 USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
2017	$ 14.3
2018	14.3
2019	14.3
2020	14.0
2021	$ 12.1

Pensions and Post-Retirement Benefit Plans - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) Plan	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2016 Participant
Defined Benefit Plan Disclosure [Line Items]
Number of domestic non-qualified defined benefit plans \| Plan	3
Defined contribution plan expense	$ 7.8	$ 6.0	$ 6.9
Amortization of net loss in 2017	2.0
Accumulated benefit obligation, pension plans	$ 243.3	255.8
Ultimate health care cost trend rate, year	2037
Operating expenses	$ 10.4	9.2	$ 3.8
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Initial health care cost trend rate	6.30%
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Initial health care cost trend rate	4.50%
Growth seeking assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation investment strategy, minimum	30.00%
Target allocation investment strategy, maximum	40.00%
Income generating assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation investment strategy, minimum	60.00%
Target allocation investment strategy, maximum	70.00%
U.S. Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of salaried terminated deferred vested participants \| Participant				375
Total amount paid out of defined benefit plan assets	$ 13.9
Pension settlement charge	(4.4)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Total amount paid out of defined benefit plan assets	13.9	0.0
Accumulated benefit obligation, pension plans	238.5	251.2
Expected contributions by employer	4.2
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Total amount paid out of defined benefit plan assets	0.0	$ 0.0
Expected contributions by employer	$ 0.8
Initial health care cost trend rate	6.30%	6.50%

Pensions and Post-Retirement Benefit Plans - Components of Net Periodic Benefit Cost for Pension Plans and Other Benefit Plans (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1.7	$ 2.0	$ 2.7
Interest cost	11.0	10.9	11.8
Expected return on plan assets	(10.5)	(12.0)	(13.9)
Amortization of prior service cost	0.0	(0.3)	(0.2)
Amortization of net loss	2.2	6.6	4.0
Settlements and curtailments	4.4	(0.8)	0.0
Net periodic benefit cost	8.8	6.4	4.4
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.1	0.1	0.1
Interest cost	0.4	0.4	0.5
Expected return on plan assets	0.0	0.0	0.0
Amortization of prior service cost	0.0	(0.1)	(0.2)
Amortization of net loss	(0.4)	(0.3)	0.0
Settlements and curtailments	0.0	0.0	0.0
Net periodic benefit cost	$ 0.1	$ 0.1	$ 0.4

Pensions and Post-Retirement Benefit Plans - Schedule of Change in Funded Status of Pension and Post-Retirement Plans (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	$ 212.4
Fair value of plan assets at end of year	200.9	$ 212.4
Noncurrent liabilities	51.6	53.6
Accumulated benefit obligation	243.3	255.8
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	257.5	275.7
Service cost	1.7	2.0	$ 2.7
Interest cost	11.0	10.9	11.8
Plan participants’ contributions	0.1	0.2
Actuarial losses (gains)	10.7	(14.9)
Plan amendments	(0.1)	0.0
Settlements	(13.9)	0.0
Currency translation	(9.9)	(3.4)
Benefits paid	(13.5)	(13.0)
Benefit obligation at end of year	243.6	257.5	275.7
Fair value of plan assets at beginning of year	212.4	229.5
Actual return on plan assets	20.8	(4.6)
Employer contribution	4.4	3.4
Settlements	(13.9)	0.0
Currency translation	(9.4)	(3.1)
Fair value of plan assets at end of year	200.9	212.4	229.5
Funded status of the plan	(42.7)	(45.1)
Noncurrent assets	0.8	0.8
Current liabilities	1.1	0.9
Noncurrent liabilities	42.4	45.0
Benefit obligation	238.7	252.7
Fair value of plan assets	195.3	206.9
Accumulated benefit obligation	238.5	251.2
Fair value of plan assets	195.3	206.9
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	9.4	9.8
Service cost	0.1	0.1	0.1
Interest cost	0.4	0.4	0.5
Plan participants’ contributions	0.0	0.0
Actuarial losses (gains)	1.0	(0.3)
Plan amendments	0.0	0.0
Settlements	0.0	0.0
Currency translation	0.0	0.0
Benefits paid	(0.9)	(0.6)
Benefit obligation at end of year	10.0	9.4	9.8
Fair value of plan assets at beginning of year	0.0	0.0
Actual return on plan assets	0.0	0.0
Employer contribution	0.9	0.6
Settlements	0.0	0.0
Currency translation	0.0	0.0
Fair value of plan assets at end of year	0.0	0.0	$ 0.0
Funded status of the plan	(10.0)	(9.4)
Noncurrent assets	0.0	0.0
Current liabilities	0.8	0.8
Noncurrent liabilities	$ 9.2	$ 8.6

Pensions and Post-Retirement Benefit Plans - Schedule of Projected Benefit Payments (Detail) $ in Millions	Dec. 31, 2016 USD ($)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2017	$ 13.0
2018	12.9
2019	13.2
2020	13.5
2021	13.8
Next five years	75.0
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2017	0.9
2018	0.9
2019	0.8
2020	0.8
2021	0.7
Next five years	$ 3.1

Pensions and Post-Retirement Benefit Plans - Schedule of Weighted-Average Assumptions (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.09%	4.52%
Expected return on plan assets	5.10%	5.16%
Rate of compensation increase	3.50%	3.82%
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.53%	4.73%
Initial medical trend rate	6.30%	6.50%

Pensions and Post-Retirement Benefit Plans - Schedule of Weighted Average Asset Allocation for Company's Pension Plans (Detail)	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Total asset allocation	100.00%	100.00%
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total asset allocation	71.00%	70.00%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total asset allocation	24.00%	26.00%
Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Total asset allocation	5.00%	4.00%

Pensions and Post-Retirement Benefit Plans - Summary of Changes in Fair Value of Pension Plan Assets (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	$ 212.4
Fair value of plan assets at end of year	200.9
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	10.0
Level 3 [Member] \| Other Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	0.0
Purchases, sales, issuances and settlements	4.4
Realized and unrealized gains	0.2
Foreign currency translation loss	(0.3)
Fair value of plan assets at end of year	4.3
The amount of total gains during the period attributable to the change in unrealized gains relating to Level 3 net assets still held at the reporting date	0.2
Level 3 [Member] \| Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	0.0
Purchases, sales, issuances and settlements	6.0
Realized and unrealized gains	0.1
Foreign currency translation loss	(0.4)
Fair value of plan assets at end of year	5.7
The amount of total gains during the period attributable to the change in unrealized gains relating to Level 3 net assets still held at the reporting date	$ 0.1

Pensions and Post-Retirement Benefit Plans - Schedule of Health Care Cost Trend Rates (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)
Postemployment Benefits [Abstract]
Postretirement benefit expense one-percentage increase	$ 0.0
Postretirement benefit liability one-percentage increase	0.2
Postretirement benefit expense one-percentage decrease	0.0
Postretirement benefit liability one-percentage decrease	$ (0.1)

Debt - Schedule of Long-Term Debt Instruments (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 01, 2009
Debt Instrument [Line Items]
Total debt	$ 671.1	$ 734.8
Less short term debt and current maturities of long-term debt	42.6	39.9
Less unamortized debt issuance costs	8.7	12.5
Long-term debt	$ 619.8	682.4
Senior Secured Credit Facilities [Member] \| Term Loan [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	4.57%
Debt, Maturity	2019
Total debt	$ 232.5	262.5
Senior Secured Credit Facilities [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	4.57%
Debt, Maturity	2019
Total debt	$ 100.1	130.0
Committed Loan Facility Agreements [Member] \| Construction Loans [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	4.87%
Debt, Maturity	2020
Total debt	$ 40.4	44.8
7 7/8 Percent Senior Notes Due 2019 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	7.88%		7.88%
Debt, Maturity	2019
Total debt	$ 298.1	$ 297.5

Debt - Additional Information (Detail) ¥ in Millions				12 Months Ended
Debt - Additional Information (Detail) ¥ in Millions	Jan. 25, 2017 USD ($)	Nov. 18, 2013 USD ($)	Dec. 01, 2009 USD ($)	Dec. 31, 2016 USD ($) Installment	Feb. 28, 2017 USD ($)	Apr. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)	Nov. 18, 2013 CNY (¥)
Debt Instrument [Line Items]
Principal value of Senior Notes				$ 673,000,000
Senior Secured Credit Facilities [Member]
Debt Instrument [Line Items]
Letters of credit, amount outstanding				43,500,000
Senior Secured Credit Facilities [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Revolving credit facility				300,000,000		$ 300,000,000
Deferred financing costs to be written off				2,000,000
Debt instrument, unused borrowing capacity				$ 159,600,000
Debt, Weighted Average Interest Rate				4.57%
Senior Secured Credit Facilities [Member] \| Term Loan Facility [Member]
Debt Instrument [Line Items]
Revolving credit facility				$ 232,500,000
Quarterly principal repayment obligations, interest rate				2.50%
Quarterly principal repayment obligations				$ 7,500,000
7 7/8 Percent Senior Notes Due 2019 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Principal value outstanding				$ 298,100,000
Debt, Weighted Average Interest Rate			7.88%	7.88%
Debt instrument, issuance date				Dec. 01, 2009
Debt instrument, offering price percentage			98.311%
Debt instrument, offering value			$ 294,900,000
Principal value of Senior Notes			$ 300,000,000
Debt instrument, effective interest rate			8.13%
Debt instrument redemption date				Feb. 24, 2017
Accumulated amortization				$ 12,000,000			$ 6,900,000
Unamortized debt issuance costs				$ 8,700,000			$ 12,500,000
6.00 percent Senior Notes due 2025 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Debt maturity date				Feb. 15, 2025
Senior notes, payment terms				The 2025 Notes will pay interest semi-annually in arrears on February 15 and August 15 beginning on August 15, 2017 and will mature on February 15, 2025 unless earlier redeemed or repurchased.
6.00 percent Senior Notes due 2025 [Member] \| Senior Notes [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Senior notes, offering value	$ 500,000,000
Senior notes, effective percentage	6.00%
Principal value of Senior Notes	$ 500,000,000
New Senior Secured Credit Facilities [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Revolving credit facility, maturity period				2022-02
New Senior Secured Credit Facilities [Member] \| Revolving Credit Facility [Member] \| Scenario, Forecast [Member]
Debt Instrument [Line Items]
Revolving credit facility					$ 400,000,000
Committed Loan Facility Agreements [Member] \| Construction Loans [Member]
Debt Instrument [Line Items]
Debt maturity date				Dec. 21, 2020
Number of installments for repayment of loans \| Installment				6
Installment frequency for repayment of loans				6 months
Commencement period of debt repayment				2018-06
Debt, Weighted Average Interest Rate				4.87%
Committed Loan Facility Agreements [Member] \| Construction Loans [Member] \| Third Party Debt [Member]
Debt Instrument [Line Items]
Construction loan facility borrowing capacity \| ¥								¥ 198.8
Committed Loan Facility Agreements [Member] \| Construction Loans [Member] \| Committed Credit Facility [Member] \| Lender [Member]
Debt Instrument [Line Items]
Construction loan facility borrowing capacity \| ¥								66.2
Committed Loan Facility Agreements [Member] \| Construction Loans [Member] \| Koppers Carbon and Chemical Company Limited [Member]
Debt Instrument [Line Items]
Percentage ownership of subsidiary		75.00%
Construction loan facility borrowing capacity		$ 44,000,000						¥ 265.0
Percentage of non-controlling shareholders		25.00%						25.00%

Debt - Schedule of Debt Maturities (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Debt Disclosure [Abstract]
2017	$ 42.6
2018	37.0
2019	575.3
2020	18.1
Total maturities	673.0
Future accretion on 2019 Notes	(1.9)
Total debt	$ 671.1	$ 734.8

Debt - Schedule of Debt Maturities (Parenthetical) (Detail) - USD ($)		1 Months Ended
	Jan. 25, 2017	Feb. 28, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Principal value of Senior Notes			$ 673,000,000
6.00 percent Senior Notes due 2025 [Member] \| Senior Notes [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Principal value of Senior Notes	$ 500,000,000
Revolving credit facility, maturity year	2025
New Senior Secured Credit Facilities [Member] \| Revolving Credit Facility [Member] \| Scenario, Forecast [Member]
Debt Instrument [Line Items]
Revolving credit facility		$ 400,000,000
Revolving credit facility, maturity year		2022

Leases - Future Minimum Commitments for Operating Leases (Detail) $ in Millions	Dec. 31, 2016 USD ($)
Leases [Abstract]
2017	$ 43.9
2018	34.0
2019	17.3
2020	13.6
2021	11.7
Thereafter	46.8
Total	$ 167.3

Leases - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Leases [Abstract]
Operating lease expense	$ 50.3	$ 46.4	$ 36.7

Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Maximum period hedged in cash flow hedge	30 months
Unrealized gains, reclassification period	12 months
Unrealized gains, net of tax, expected to be reclassified from other comprehensive income (loss)into earnings	$ 4.1
Not Designated as Hedging Instrument [Member] \| Forward Contracts [Member]
Derivative [Line Items]
Net Fair Value - Asset (Liability)	1.0
Accrued Liabilities [Member] \| Not Designated as Hedging Instrument [Member] \| Forward Contracts [Member]
Derivative [Line Items]
Net Fair Value - Asset (Liability)		$ (1.9)
Gross derivative liability	0.9
Other Current Assets [Member] \| Not Designated as Hedging Instrument [Member] \| Forward Contracts [Member]
Derivative [Line Items]
Gross derivative assets	$ 1.9

Derivative Financial Instruments - Outstanding Copper Swap Contracts (Detail) - Copper Swap Contracts [Member] £ in Millions, $ in Millions	Dec. 31, 2016 USD ($)	Dec. 31, 2016 GBP (£)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 GBP (£)
Derivatives Fair Value [Line Items]
Copper Swap Contracts Units Outstanding \| £		£ 49.1		£ 21.3
Net Fair Value - Asset (Liability) \| $	$ 11.6		$ (10.5)
Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Derivatives Fair Value [Line Items]
Copper Swap Contracts Units Outstanding \| £		42.6		17.3
Net Fair Value - Asset (Liability) \| $	10.6		(9.8)
Not Designated as Hedging Instrument [Member]
Derivatives Fair Value [Line Items]
Copper Swap Contracts Units Outstanding \| £		£ 6.5		£ 4.0
Net Fair Value - Asset (Liability) \| $	$ 1.0		$ (0.7)

Derivative Financial Instruments - Schedule of Fair Value of Outstanding Copper Swap Contracts Recorded in Balance Sheet (Detail) - Copper Swap Contracts [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Net Fair Value - Asset (Liability)	$ 11.6	$ (10.5)
Accumulated other comprehensive gain (loss), net of tax	6.9	(6.1)
Other Current Assets [Member]
Derivative [Line Items]
Net Fair Value - Asset (Liability)	12.5	0.1
Accrued Liabilities [Member]
Derivative [Line Items]
Net Fair Value - Asset (Liability)	$ (0.9)	$ (10.6)

Derivative Financial Instruments - Schedule of Amounts Recognized In Earnings Related To Copper Swap Contracts (Detail) - Copper Swap Contracts [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Gain (loss) from contracts not designated as hedges	$ 1.7	$ (0.7)
Net	1.3	(0.8)
Cash Flow Hedging [Member]
Derivative [Line Items]
Gain (loss) from ineffectiveness of cash flow hedges	$ (0.4)	$ (0.1)

Derivative Financial Instruments - Schedule Of Net Currency Units Outstanding (Detail)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 GBP (£)	Dec. 31, 2016 NZD ($)	Dec. 31, 2016 CAD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 GBP (£)	Dec. 31, 2015 NZD ($)	Dec. 31, 2015 CAD ($)
Offsetting [Abstract]
Net currency units outstanding	$ 24,700,000	£ 7,300,000	$ 15,500,000	$ 300,000	$ 40,000,000	£ 5,900,000	$ 22,500,000	$ 0

Common Stock and Senior Convertible Preferred Stock - Schedule of Changes in Senior Convertible Preferred Stock, Common Stock and Treasury Stock (Detail) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Equity [Abstract]
Senior Convertible Preferred Stock, balance at beginning and end of year	0	0	0
Common Stock, balance at beginning of year	22,015,994	21,938,000	21,722,000
Common Stock, issued for employee stock plans	125,000	78,000	216,000
Common Stock, balance at end of year	22,140,680	22,015,994	21,938,000
Treasury Stock, balance at beginning of year	(1,459,164)	(1,443,000)	(1,390,000)
Treasury Stock, shares repurchased	(17,000)	(16,000)	(53,000)
Treasury Stock, balance at end of year	(1,475,792)	(1,459,164)	(1,443,000)

Commitments and Contingent Liabilities - Additional Information (Detail)	1 Months Ended	12 Months Ended
	Jul. 31, 2004 USD ($)	Dec. 31, 2016 USD ($) State Plaintiff Case Owner site Party Plant mi	Dec. 31, 2015 USD ($) Plaintiff Case	Jun. 30, 2016 USD ($)	Dec. 31, 2014 USD ($)
Loss Contingencies [Line Items]
Number of states with new claims filed \| State		2
Number of plaintiffs \| Plaintiff		99	110
Environmental remediation and regulation liability		$ 12,900,000	$ 19,800,000		$ 7,800,000
Accrued liability for environmental matters, current		5,200,000	$ 7,000,000
Portland Harbor and Newark Bay CERCLA sites [Member]
Loss Contingencies [Line Items]
Costs of participating in PRP group		$ 2,000,000
Beazer East [Member]
Loss Contingencies [Line Items]
Environmental legal indemnification expense	$ 7,000,000
Sites listed on National Priorities List \| site		1
Compensatory Damages [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		55
Punitive Damages [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		50
Indemnification Agreement [Member] \| Beazer East [Member]
Loss Contingencies [Line Items]
Environmental remediation costs paid by others, per year		$ 10,000,000
Coal Tar Pitch Cases [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		55	59
Reserve for legal proceedings		$ 0
Gainesville Class Action Complaint [Member]
Loss Contingencies [Line Items]
Reserve for legal proceedings		$ 0
Single family residential properties extension sought by plaintiffs from former plant area \| mi		2
Single family residential properties, number of owners \| Owner		7,000
Pennsylvania [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		54
Pennsylvania [Member] \| Coal Tar Pitch Cases [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		54
Tennessee [Member] \| Coal Tar Pitch Cases [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		1
Compensatory damages		$ 15,000,000
Oregon [Member] \| Portland Harbor CERCLA site [Member]
Loss Contingencies [Line Items]
Number of potential responsible parties \| Party		80
Net present value of selected remedy estimation		$ 1,100,000,000
Undiscounted cost of selected remedy estimation		$ 1,700,000,000
United States [Member] \| Osmose Holdings, Inc. [Member]
Loss Contingencies [Line Items]
Number of plant sites \| Plant		2
Environmental remediation and regulation liability		$ 4,900,000
United Kingdom And Australia [Member] \| Osmose Holdings, Inc. [Member]
Loss Contingencies [Line Items]
Environmental legal indemnification expense		$ 5,000,000
Number of plant sites \| Plant		3
Environmental remediation and regulation liability		$ 3,500,000
Amount contributable by third party		1,900,000
United Kingdom [Member] \| Osmose Holdings, Inc. [Member]
Loss Contingencies [Line Items]
Amount contributable by third party				$ 2,900,000
Australia [Member] \| Continental Carbon facility [Member]
Loss Contingencies [Line Items]
Environmental remediation and regulation liability		$ 1,500,000

Commitments and Contingent Liabilities - Changes in Accrued Liability for Environmental Matters (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Commitments And Contingencies Disclosure [Abstract]
Balance at beginning of year	$ 19.8	$ 7.8
Expense	1.5	1.2
Reversal of reserves	(1.0)	(0.5)
Cash expenditures	(6.3)	(1.4)
Acquisition of Osmose Entities	0.0	13.7
Divestitures	(0.3)	0.0
Currency translation	(0.8)	(1.0)
Balance at end of period	$ 12.9	$ 19.8

Selected Quarterly Financial Data - Schedule of Selected Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of operations data:
Net sales	$ 313.2	$ 371.1	$ 385.1	$ 346.8	$ 363.7	$ 433.8	$ 431.6	$ 397.8	$ 1,416.2	$ 1,626.9	$ 1,555.0
Operating (loss) profit	18.9	27.7	32.0	7.8	(90.6)	27.0	26.0	8.0	86.4	(29.6)	33.2
Income (loss) from continuing operations	6.2	12.0	11.3	(2.4)	(88.8)	9.2	7.9	(4.2)	27.1	(75.9)	(40.0)
Net income (loss)	6.3	11.9	11.3	(1.8)	(88.8)	9.1	7.9	(4.2)	27.7	(76.0)	(39.4)
Net income (loss) attributable to Koppers	$ 6.4	$ 12.1	$ 12.1	$ (1.3)	$ (87.7)	$ 10.1	$ 9.0	$ (3.4)	$ 29.3	$ (72.0)	$ (32.4)
Basic -
Continuing operations	$ 0.31	$ 0.59	$ 0.58	$ (0.09)	$ (4.27)	$ 0.49	$ 0.44	$ (0.16)	$ 1.39	$ (3.50)	$ (1.61)
Discontinued operations	0.00	0.00	0.00	0.03	0.00	(0.01)	0.00	0.00	0.03	(0.01)	0.03
Earnings (loss) per basic common share	0.31	0.59	0.58	(0.06)	(4.27)	0.48	0.44	(0.16)	1.42	(3.51)	(1.58)
Diluted -
Continuing operations	0.30	0.58	0.57	(0.09)	(4.27)	0.49	0.44	(0.16)	1.36	(3.50)	(1.61)
Discontinued operations	0.00	0.00	0.00	0.03	0.00	(0.01)	0.00	0.00	0.03	(0.01)	0.03
Earnings (loss) per diluted common share	0.30	0.58	0.57	(0.06)	(4.27)	0.48	0.44	(0.16)	1.39	(3.51)	$ (1.58)
Maximum [Member]
Diluted -
Price range of common stock	42.70	33.71	31.35	23.43	23.63	24.86	27.40	26.44	42.70	27.40
Minimum [Member]
Diluted -
Price range of common stock	$ 31.28	$ 28.54	$ 21.38	$ 13.58	$ 17.34	$ 17.88	$ 19.26	$ 15.78	$ 13.58	$ 15.78

Selected Quarterly Financial Data - Schedule of Selected Quarterly Financial Data (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Impairment charges	$ 35.1	$ 3.5	$ 14.7	$ 4.7
Goodwill impairment	$ 67.2	$ 0.0	$ 67.2	$ 0.0

Subsidiary Guarantor Information for Koppers Inc. 2025 Notes and Shelf Registration - Additional Information (Detail) - USD ($)		12 Months Ended
	Jan. 25, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Principal value of Senior Notes		$ 673,000,000
Domestic Guarantor Subsidiaries [Member]
Debt Instrument [Line Items]
Cash dividends paid		1,200,000	$ 6,500,000	$ 23,600,000
Domestic Guarantor Subsidiaries [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		400,000,000
Koppers Inc. [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Amount of assets exceeded liabilities		$ 29,800,000
Subsequent Event [Member] \| Senior Notes [Member] \| 6.00 percent Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Principal value of Senior Notes	$ 500,000,000
Subsequent Event [Member] \| Domestic Guarantor Subsidiaries [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Percentage ownership of subsidiary	100.00%

Subsidiary Guarantor Information for Koppers Inc. 2025 Notes and Shelf Registration - Condensed Consolidating Statement of Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Statement Of Income Captions [Line Items]
Net sales	$ 313.2	$ 371.1	$ 385.1	$ 346.8	$ 363.7	$ 433.8	$ 431.6	$ 397.8	$ 1,416.2	$ 1,626.9	$ 1,555.0
Cost of sales including depreciation and amortization									1,200.9	1,467.9	1,405.6
Gain on sale of business									(2.1)	(3.2)	0.0
Goodwill impairment					67.2				0.0	67.2	0.0
Selling, general and administrative									131.0	124.6	116.2
Operating profit (loss)	18.9	27.7	32.0	7.8	(90.6)	27.0	26.0	8.0	86.4	(29.6)	33.2
Other income (loss)									2.9	0.2	0.0
Equity income of subsidiaries									0.0	0.0	0.0
Interest (income) expense									50.8	50.7	39.1
Income taxes									11.4	(4.2)	34.1
Income (loss) from continuing operations	6.2	12.0	11.3	(2.4)	(88.8)	9.2	7.9	(4.2)	27.1	(75.9)	(40.0)
Discontinued operations									0.6	(0.1)	0.6
Noncontrolling interests									(1.6)	(4.0)	(7.0)
Net income (loss) attributable to Koppers	$ 6.4	$ 12.1	$ 12.1	$ (1.3)	$ (87.7)	$ 10.1	$ 9.0	$ (3.4)	29.3	(72.0)	(32.4)
Comprehensive income (loss) attributable to Koppers									40.5	(91.5)	(82.5)
Consolidation Eliminations [Member]
Condensed Statement Of Income Captions [Line Items]
Net sales									(99.8)	(100.7)	(67.4)
Cost of sales including depreciation and amortization									(101.2)	(99.4)	(66.7)
Gain on sale of business									0.0	0.0
Goodwill impairment										0.0
Selling, general and administrative									0.0	0.0	0.0
Operating profit (loss)									1.4	(1.3)	(0.7)
Other income (loss)									(1.8)	(2.0)	(4.3)
Equity income of subsidiaries									(145.6)	97.8	53.3
Interest (income) expense									(1.8)	(2.0)	(4.3)
Income taxes									0.0	(0.3)	0.0
Income (loss) from continuing operations									(144.2)	96.8	52.6
Discontinued operations									0.0	0.0	0.0
Noncontrolling interests									0.0	0.0	0.0
Net income (loss) attributable to Koppers									(144.2)	96.8	52.6
Comprehensive income (loss) attributable to Koppers									(155.9)	150.2	170.6
Parent [Member] \| Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Net sales									0.0	0.0	0.0
Cost of sales including depreciation and amortization									0.0	0.0	0.0
Gain on sale of business									0.0	0.0
Goodwill impairment										0.0
Selling, general and administrative									1.9	1.9	2.2
Operating profit (loss)									(1.9)	(1.9)	(2.2)
Other income (loss)									0.0	0.0	0.0
Equity income of subsidiaries									30.6	(70.8)	(31.0)
Interest (income) expense									0.0	0.0	0.0
Income taxes									(0.6)	(0.7)	(0.8)
Income (loss) from continuing operations									29.3	(72.0)	(32.4)
Discontinued operations									0.0	0.0	0.0
Noncontrolling interests									0.0	0.0	0.0
Net income (loss) attributable to Koppers									29.3	(72.0)	(32.4)
Comprehensive income (loss) attributable to Koppers									40.5	(91.5)	(82.5)
Koppers Inc. [Member] \| Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Net sales									660.7	791.1	795.9
Cost of sales including depreciation and amortization									637.4	771.7	724.5
Gain on sale of business									0.0	(3.2)
Goodwill impairment										43.1
Selling, general and administrative									47.7	41.3	59.2
Operating profit (loss)									(24.4)	(61.8)	12.2
Other income (loss)									0.3	0.5	0.2
Equity income of subsidiaries									79.1	0.9	(15.9)
Interest (income) expense									47.6	45.8	36.5
Income taxes									(23.2)	(35.4)	(9.0)
Income (loss) from continuing operations									30.6	(70.8)	(31.0)
Discontinued operations									0.0	0.0	0.0
Noncontrolling interests									0.0	0.0	0.0
Net income (loss) attributable to Koppers									30.6	(70.8)	(31.0)
Comprehensive income (loss) attributable to Koppers									41.3	(90.3)	(81.1)
Domestic Guarantor Subsidiaries [Member] \| Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Net sales									350.6	335.6	143.0
Cost of sales including depreciation and amortization									252.3	233.2	108.8
Gain on sale of business									0.0	0.0
Goodwill impairment										24.1
Selling, general and administrative									38.2	37.8	17.4
Operating profit (loss)									60.1	40.5	16.8
Other income (loss)									4.1	4.1	4.7
Equity income of subsidiaries									35.9	(27.9)	(6.4)
Interest (income) expense									0.0	0.0	0.0
Income taxes									22.2	15.8	30.5
Income (loss) from continuing operations									77.9	0.9	(15.4)
Discontinued operations									0.0	0.0	(0.6)
Noncontrolling interests									0.0	0.0	0.0
Net income (loss) attributable to Koppers									77.9	0.9	(16.0)
Comprehensive income (loss) attributable to Koppers									85.0	(18.1)	(54.4)
Non-Guarantor Subsidiaries [Member] \| Reportable Legal Entities [Member]
Condensed Statement Of Income Captions [Line Items]
Net sales									504.7	600.9	683.5
Cost of sales including depreciation and amortization									412.4	562.4	639.0
Gain on sale of business									(2.1)	0.0
Goodwill impairment										0.0
Selling, general and administrative									43.2	43.6	37.4
Operating profit (loss)									51.2	(5.1)	7.1
Other income (loss)									0.3	(2.4)	(0.6)
Equity income of subsidiaries									0.0	0.0	0.0
Interest (income) expense									5.0	6.9	6.9
Income taxes									13.0	16.4	13.4
Income (loss) from continuing operations									33.5	(30.8)	(13.8)
Discontinued operations									0.6	(0.1)	1.2
Noncontrolling interests									(1.6)	(4.0)	(7.0)
Net income (loss) attributable to Koppers									35.7	(26.9)	(5.6)
Comprehensive income (loss) attributable to Koppers									$ 29.6	$ (41.8)	$ (35.1)

Subsidiary Guarantor Information for Koppers Inc. 2025 Notes and Shelf Registration - Condensed Consolidating Balance Sheet (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets
Cash and cash equivalents	$ 20.8	$ 21.8	$ 51.1	$ 82.2
Receivables, net	140.6	159.6
Affiliated receivables	0.0	0.0
Inventories, net	228.7	226.4
Deferred tax assets		0.0
Other current assets	48.0	36.5
Total current assets	438.1	444.3
Equity investments	0.0	0.0
Property, plant and equipment, net	280.8	277.8
Goodwill	186.4	186.6	247.2
Intangible assets, net	141.9	156.1
Deferred tax assets	27.1	36.6
Affiliated loan receivables	0.0	0.0
Other assets	13.2	11.5
Total assets	1,087.5	1,112.9
LIABILITIES AND EQUITY
Accounts payable	144.2	140.8
Affiliated payables	0.0	0.0
Accrued liabilities	106.3	99.8
Current maturities of long-term debt	42.6	39.9
Total current liabilities	293.1	280.5
Long-term debt	619.8	682.4
Affiliated debt	0.0	0.0
Other long-term liabilities	140.0	162.4
Total liabilities	1,052.9	1,125.3
Koppers shareholders’ equity	30.4	(18.5)
Noncontrolling interests	4.2	6.1
Total liabilities and equity (deficit)	1,087.5	1,112.9
Consolidation Eliminations [Member]
Assets
Cash and cash equivalents	0.0	0.0	0.0	0.0
Receivables, net	0.0	0.0
Affiliated receivables	(83.1)	(33.9)
Inventories, net	(0.8)	(2.2)
Deferred tax assets		0.0
Other current assets	0.3	0.0
Total current assets	(83.6)	(36.1)
Equity investments	(922.7)	(849.9)
Property, plant and equipment, net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Deferred tax assets	0.0	0.3
Affiliated loan receivables	(264.1)	(284.6)
Other assets	0.0	0.0
Total assets	(1,270.4)	(1,170.3)
LIABILITIES AND EQUITY
Accounts payable	0.0	0.0
Affiliated payables	(91.2)	(42.8)
Accrued liabilities	0.0	0.0
Current maturities of long-term debt	0.0	0.0
Total current liabilities	(91.2)	(42.8)
Long-term debt	0.0	0.0
Affiliated debt	(264.1)	(283.9)
Other long-term liabilities	0.0	0.0
Total liabilities	(355.3)	(326.7)
Koppers shareholders’ equity	(915.1)	(843.6)
Noncontrolling interests	0.0	0.0
Total liabilities and equity (deficit)	(1,270.4)	(1,170.3)
Parent [Member] \| Reportable Legal Entities [Member]
Assets
Cash and cash equivalents	0.0	0.0	0.0	0.0
Receivables, net	0.0	0.0
Affiliated receivables	0.7	0.0
Inventories, net	0.0	0.0
Deferred tax assets		0.0
Other current assets	0.0	0.0
Total current assets	0.7	0.0
Equity investments	29.9	(19.0)
Property, plant and equipment, net	0.0	0.0
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Deferred tax assets	0.0	0.0
Affiliated loan receivables	0.0	0.7
Other assets	0.0	(0.2)
Total assets	30.6	(18.5)
LIABILITIES AND EQUITY
Accounts payable	0.2	0.0
Affiliated payables	0.0	0.0
Accrued liabilities	0.0	0.0
Current maturities of long-term debt	0.0	0.0
Total current liabilities	0.2	0.0
Long-term debt	0.0	0.0
Affiliated debt	0.0	0.0
Other long-term liabilities	0.0	0.0
Total liabilities	0.2	0.0
Koppers shareholders’ equity	30.4	(18.5)
Noncontrolling interests	0.0	0.0
Total liabilities and equity (deficit)	30.6	(18.5)
Koppers Inc. [Member] \| Reportable Legal Entities [Member]
Assets
Cash and cash equivalents	0.0	0.1	0.0	29.9
Receivables, net	50.8	60.4
Affiliated receivables	34.8	14.3
Inventories, net	106.6	111.9
Deferred tax assets		0.0
Other current assets	5.1	3.7
Total current assets	197.3	190.4
Equity investments	697.4	703.2
Property, plant and equipment, net	126.7	117.5
Goodwill	0.8	0.8
Intangible assets, net	7.9	8.7
Deferred tax assets	29.7	29.8
Affiliated loan receivables	36.9	29.6
Other assets	5.5	4.5
Total assets	1,102.2	1,084.5
LIABILITIES AND EQUITY
Accounts payable	69.6	73.8
Affiliated payables	46.0	16.6
Accrued liabilities	49.5	35.6
Current maturities of long-term debt	30.2	30.2
Total current liabilities	195.3	156.2
Long-term debt	592.0	647.5
Affiliated debt	209.9	217.5
Other long-term liabilities	75.0	81.6
Total liabilities	1,072.2	1,102.8
Koppers shareholders’ equity	30.0	(18.3)
Noncontrolling interests	0.0	0.0
Total liabilities and equity (deficit)	1,102.2	1,084.5
Domestic Guarantor Subsidiaries [Member] \| Reportable Legal Entities [Member]
Assets
Cash and cash equivalents	0.0	0.7	0.9	0.1
Receivables, net	25.4	23.7
Affiliated receivables	32.2	15.2
Inventories, net	23.9	24.9
Deferred tax assets		0.0
Other current assets	13.4	1.9
Total current assets	94.9	66.4
Equity investments	195.4	165.7
Property, plant and equipment, net	39.6	41.2
Goodwill	153.1	153.1
Intangible assets, net	107.1	117.6
Deferred tax assets	(8.4)	0.8
Affiliated loan receivables	205.3	222.6
Other assets	6.1	4.9
Total assets	793.1	772.3
LIABILITIES AND EQUITY
Accounts payable	38.9	18.9
Affiliated payables	20.7	10.9
Accrued liabilities	18.9	23.4
Current maturities of long-term debt	0.0	0.0
Total current liabilities	78.5	53.2
Long-term debt	0.0	0.0
Affiliated debt	23.5	29.5
Other long-term liabilities	11.6	13.2
Total liabilities	113.6	95.9
Koppers shareholders’ equity	679.5	676.4
Noncontrolling interests	0.0	0.0
Total liabilities and equity (deficit)	793.1	772.3
Non-Guarantor Subsidiaries [Member] \| Reportable Legal Entities [Member]
Assets
Cash and cash equivalents	20.8	21.0	$ 50.2	$ 52.2
Receivables, net	64.4	75.5
Affiliated receivables	15.4	4.4
Inventories, net	99.0	91.8
Deferred tax assets		0.0
Other current assets	29.2	30.9
Total current assets	228.8	223.6
Equity investments	0.0	0.0
Property, plant and equipment, net	114.5	119.1
Goodwill	32.5	32.7
Intangible assets, net	26.9	29.8
Deferred tax assets	5.8	5.7
Affiliated loan receivables	21.9	31.7
Other assets	1.6	2.3
Total assets	432.0	444.9
LIABILITIES AND EQUITY
Accounts payable	35.5	48.1
Affiliated payables	24.5	15.3
Accrued liabilities	37.9	40.8
Current maturities of long-term debt	12.4	9.7
Total current liabilities	110.3	113.9
Long-term debt	27.8	34.9
Affiliated debt	30.7	36.9
Other long-term liabilities	53.4	67.6
Total liabilities	222.2	253.3
Koppers shareholders’ equity	205.6	185.5
Noncontrolling interests	4.2	6.1
Total liabilities and equity (deficit)	$ 432.0	$ 444.9

Subsidiary Guarantor Information for Koppers Inc. 2025 Notes and Shelf Registration - Condensed Consolidating Statement of Cash Flows (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Subsidiary, Sale of Stock [Line Items]
Cash provided by (used in) operating activities	$ 119.5	$ 127.7	$ 35.5
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions	(49.9)	(56.0)	(580.3)
Repayments (loans to) from affiliates	0.0	0.0	0.0
Net cash proceeds (payments) from divestitures and asset sales	(3.8)	14.9	0.3
Net cash used in investing activities	(53.7)	(41.1)	(580.0)
Cash provided by (used in) financing activities:
(Repayments) borrowings of long-term debt	(61.4)	(113.4)	547.5
Borrowings (repayments) of affiliated debt	0.0	0.0	0.0
Deferred financing costs	(1.4)	(1.0)	(11.1)
Other financing receipts			1.4
Dividends paid	0.0	(8.7)	(20.4)
Stock (repurchased) issued	0.1	(0.3)	(1.3)
Net cash (used in) provided by financing activities	(62.7)	(123.4)	516.1
Effect of exchange rates on cash	(4.1)	7.5	(2.7)
Net increase (decrease) in cash and cash equivalents	(1.0)	(29.3)	(31.1)
Cash and cash equivalents at beginning of period	21.8	51.1	82.2
Cash and cash equivalents at end of period	20.8	21.8	51.1
Consolidation Eliminations [Member]
Subsidiary, Sale of Stock [Line Items]
Cash provided by (used in) operating activities	(93.1)	(56.9)	(54.3)
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions	0.0	0.0	14.8
Repayments (loans to) from affiliates	(19.8)	(10.4)	71.1
Net cash proceeds (payments) from divestitures and asset sales	0.0	0.0	0.0
Net cash used in investing activities	(19.8)	(10.4)	85.9
Cash provided by (used in) financing activities:
(Repayments) borrowings of long-term debt	0.0	0.0	0.0
Borrowings (repayments) of affiliated debt	19.8	10.4	(71.1)
Deferred financing costs	0.0	0.0	0.0
Other financing receipts			0.0
Dividends paid	93.1	56.9	54.3
Stock (repurchased) issued	0.0	0.0	(14.8)
Net cash (used in) provided by financing activities	112.9	67.3	(31.6)
Effect of exchange rates on cash	0.0	0.0	0.0
Net increase (decrease) in cash and cash equivalents	0.0	0.0	0.0
Cash and cash equivalents at beginning of period	0.0	0.0	0.0
Cash and cash equivalents at end of period	0.0	0.0	0.0
Parent [Member] \| Reportable Legal Entities [Member]
Subsidiary, Sale of Stock [Line Items]
Cash provided by (used in) operating activities	(0.1)	5.4	21.8
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions	0.0	0.0	0.0
Repayments (loans to) from affiliates	0.0	0.0	0.0
Net cash proceeds (payments) from divestitures and asset sales	0.0	0.0	0.0
Net cash used in investing activities	0.0	0.0	0.0
Cash provided by (used in) financing activities:
(Repayments) borrowings of long-term debt	0.0	0.0	0.0
Borrowings (repayments) of affiliated debt	0.0	0.0	0.0
Deferred financing costs	0.0	0.0	0.0
Other financing receipts			0.0
Dividends paid	0.0	(5.1)	(20.5)
Stock (repurchased) issued	0.1	(0.3)	(1.3)
Net cash (used in) provided by financing activities	0.1	(5.4)	(21.8)
Effect of exchange rates on cash	0.0	0.0	0.0
Net increase (decrease) in cash and cash equivalents	0.0	0.0	0.0
Cash and cash equivalents at beginning of period	0.0	0.0	0.0
Cash and cash equivalents at end of period	0.0	0.0	0.0
Koppers Inc. [Member] \| Reportable Legal Entities [Member]
Subsidiary, Sale of Stock [Line Items]
Cash provided by (used in) operating activities	106.6	63.0	23.8
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions	(30.1)	(41.2)	(518.5)
Repayments (loans to) from affiliates	(6.9)	6.3	(32.2)
Net cash proceeds (payments) from divestitures and asset sales	0.0	12.3	0.1
Net cash used in investing activities	(37.0)	(22.6)	(550.6)
Cash provided by (used in) financing activities:
(Repayments) borrowings of long-term debt	(59.9)	(104.2)	497.0
Borrowings (repayments) of affiliated debt	(7.2)	71.0	35.8
Deferred financing costs	(1.4)	(1.0)	(11.1)
Other financing receipts			0.0
Dividends paid	(1.2)	(6.2)	(23.6)
Stock (repurchased) issued	0.0	0.0	0.0
Net cash (used in) provided by financing activities	(69.7)	(40.4)	498.1
Effect of exchange rates on cash	0.0	0.1	(1.2)
Net increase (decrease) in cash and cash equivalents	(0.1)	0.1	(29.9)
Cash and cash equivalents at beginning of period	0.1	0.0	29.9
Cash and cash equivalents at end of period	0.0	0.1	0.0
Domestic Guarantor Subsidiaries [Member] \| Reportable Legal Entities [Member]
Subsidiary, Sale of Stock [Line Items]
Cash provided by (used in) operating activities	77.0	55.9	33.8
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions	(7.1)	(5.3)	(16.7)
Repayments (loans to) from affiliates	16.9	(5.1)	(38.9)
Net cash proceeds (payments) from divestitures and asset sales	0.9	2.1	0.1
Net cash used in investing activities	10.7	(8.3)	(55.5)
Cash provided by (used in) financing activities:
(Repayments) borrowings of long-term debt	0.1	0.1	0.0
Borrowings (repayments) of affiliated debt	(6.5)	(6.4)	27.6
Deferred financing costs	0.0	0.0	0.0
Other financing receipts			0.0
Dividends paid	(82.0)	(40.8)	(6.1)
Stock (repurchased) issued	0.0	0.0	0.0
Net cash (used in) provided by financing activities	(88.4)	(47.1)	21.5
Effect of exchange rates on cash	0.0	(0.7)	1.0
Net increase (decrease) in cash and cash equivalents	(0.7)	(0.2)	0.8
Cash and cash equivalents at beginning of period	0.7	0.9	0.1
Cash and cash equivalents at end of period	0.0	0.7	0.9
Non-Guarantor Subsidiaries [Member] \| Reportable Legal Entities [Member]
Subsidiary, Sale of Stock [Line Items]
Cash provided by (used in) operating activities	29.1	60.3	10.4
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions	(12.7)	(9.5)	(59.9)
Repayments (loans to) from affiliates	9.8	9.2	0.0
Net cash proceeds (payments) from divestitures and asset sales	(4.7)	0.5	0.1
Net cash used in investing activities	(7.6)	0.2	(59.8)
Cash provided by (used in) financing activities:
(Repayments) borrowings of long-term debt	(1.6)	(9.3)	50.5
Borrowings (repayments) of affiliated debt	(6.1)	(75.0)	7.7
Deferred financing costs	0.0	0.0	0.0
Other financing receipts			1.4
Dividends paid	(9.9)	(13.5)	(24.5)
Stock (repurchased) issued	0.0	0.0	14.8
Net cash (used in) provided by financing activities	(17.6)	(97.8)	49.9
Effect of exchange rates on cash	(4.1)	8.1	(2.5)
Net increase (decrease) in cash and cash equivalents	(0.2)	(29.2)	(2.0)
Cash and cash equivalents at beginning of period	21.0	50.2	52.2
Cash and cash equivalents at end of period	$ 20.8	$ 21.0	$ 50.2

Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$ 6.5	$ 5.6	$ 3.6
Business Acquisition	0.0	0.0	2.6
Increase (Decrease) to Expense	0.7	1.3	(0.2)
Net (Write- Offs) Recoveries	(3.4)	0.0	0.0
Currency Translation	0.0	(0.4)	(0.4)
Balance at End of Year	3.8	6.5	5.6
Inventory Obsolescence Reserves [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	2.3	3.4	1.7
Business Acquisition	0.0	0.0	0.8
Increase (Decrease) to Expense	(0.4)	(1.0)	1.0
Net (Write- Offs) Recoveries	0.0	0.0	0.0
Currency Translation	0.0	(0.1)	(0.1)
Balance at End of Year	1.9	2.3	3.4
Deferred Tax Valuation Allowance [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	41.9	32.4	19.7
Business Acquisition	0.0	0.0	1.5
Increase (Decrease) to Expense	0.9	10.1	11.4
Net (Write- Offs) Recoveries	(1.5)	0.0	0.0
Currency Translation	(1.1)	(0.6)	(0.2)
Balance at End of Year	$ 40.2	$ 41.9	$ 32.4

Pensions and Post-Retirement Benefit Plans - Schedule of Pension Plan Assets at Fair Value (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	$ 200.9	$ 212.4
Quoted prices in active markets for identical assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	62.9	66.4
Significant observable inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	128.0	146.0
Significant unobservable inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	10.0	0.0
U.S. equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	25.5	25.2
U.S. equity securities [Member] \| Quoted prices in active markets for identical assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	12.3	15.0
U.S. equity securities [Member] \| Significant observable inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	13.2	10.2
U.S. equity securities [Member] \| Significant unobservable inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.0	0.0
International equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	23.5	30.7
International equity securities [Member] \| Quoted prices in active markets for identical assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	12.6	12.1
International equity securities [Member] \| Significant observable inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	10.9	18.6
International equity securities [Member] \| Significant unobservable inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.0	0.0
U.S. debt securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	108.1	117.1
U.S. debt securities [Member] \| Quoted prices in active markets for identical assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	29.7	32.3
U.S. debt securities [Member] \| Significant observable inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	75.2	84.8
U.S. debt securities [Member] \| Significant unobservable inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	3.2	0.0
International debt securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	33.7	32.5
International debt securities [Member] \| Quoted prices in active markets for identical assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	8.3	7.0
International debt securities [Member] \| Significant observable inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	24.3	25.5
International debt securities [Member] \| Significant unobservable inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	1.1	0.0
Real estate and other investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	6.2	1.4
Real estate and other investments [Member] \| Quoted prices in active markets for identical assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.0	0.0
Real estate and other investments [Member] \| Significant observable inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.5	1.4
Real estate and other investments [Member] \| Significant unobservable inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	5.7	0.0
Cash & Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	3.9	5.5
Cash & Cash Equivalents [Member] \| Quoted prices in active markets for identical assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.0	0.0
Cash & Cash Equivalents [Member] \| Significant observable inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	3.9	5.5
Cash & Cash Equivalents [Member] \| Significant unobservable inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	$ 0.0	$ 0.0