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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 segment also operates a railroad services business that conducts engineering, design, repair and inspection services for railroad bridges and a business related to the recovery of used crossties.

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, 2018

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 50 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. As of November 2016, the Company had no investments under the equity method of accounting. 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.

Revenue recognition – Effective January 1, 2018 the Company adopted Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers, using the modified retrospective method. The Company recognized the cumulative effect of initially applying the new revenue standard as an adjustment to the opening balance of retained earnings. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods.

Revenue is recognized upon the completion of performance obligations under the Company’s contracts with customers and when control of a good or service is transferred to the customer. Substantially all of the Company’s contracts with its customers are ship and invoice arrangements where revenue is recognized when the Company completes its’ performance obligations and transfers control to the customer. Revenue recognition generally occurs at the point of shipment; however in certain circumstances as shipping terms dictate, the Company transfers control and revenue is recognized at the point of destination. Payment terms on ship and invoice arrangements are typically within 45 days. 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 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 and the performance obligation is satisfied. Payment on sales of untreated railroad crossties and wood treating services are generally due within 30 days of the invoice date.

For periods prior to January 1, 2018 the Company recognized revenue when the risks and rewards of ownership and title to the product have transferred to the customer. Revenue recognition generally occurred at the point of shipment; however in certain circumstances as shipping terms dictate, the Company recognized revenue at the point of destination.

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, and net realizable value. Net realizable value is the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. LIFO inventories constituted approximately 53 percent and 52 percent of the FIFO inventory value at December 31, 2018 and 2017, respectively. In 2018, 2017 and 2016, we recorded inventory write-downs of $1.0 million, $0.4 million and $0.6 million, respectively, related to lower of cost and net realizable value 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 2018 and 2017, noting no impairment.

Identifiable intangible assets, other than goodwill, are recorded at fair value. 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.

Asset retirement obligations – Asset retirement obligations are initially recorded at present value and are capitalized as part of the cost of the related long-lived asset when sufficient information is available to estimate present value. The capitalized costs are subsequently charged to depreciation expense over the estimated useful life of the related long-lived asset. The present 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 fair 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:

	December 31,
	2018			2017
(Dollars in millions)
Asset retirement obligation at beginning of year	$	37.1		$	36.0
Accretion expense		1.7			2.4
Revision in estimated cash flows ^(a)		0.8			9.4
Cash expenditures		(12.5	)		(10.9	)
Currency translation		(0.1	)		0.2
Balance at end of period	$	27.0		$	37.1

(a) Revision in estimated cash flows for 2018 and 2017 includes $1.8 and $4.7 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.

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.

New Accounting Pronouncements

12 Months Ended

Dec. 31, 2018

Accounting Changes And Error Corrections [Abstract]

New Accounting Pronouncements

3. New Accounting Pronouncements

The Company adopted Accounting Standards Update (“ASU”) No. 2018-02, “Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income” effective October 1, 2017. ASU 2018-02 requires a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the newly enacted federal corporate income tax rate. The amount of the reclassification is the difference between the tax-effected items that are included in accumulated other comprehensive income and were recorded at the historical 35 percent corporate income tax rate and those same items that are now recorded at the newly enacted 21 percent corporate income tax rate. This difference was $3.2 million for the year ended December 31, 2017.

In August 2018, the Securities and Exchange Commission (“SEC”) issued SEC Release No. 33-10532, “Disclosure Update and Simplification”, which expanded the interim period disclosure requirements for stockholders' equity. Under the release, a reconciliation of the changes in each caption of stockholders' equity must be provided in a note or separate statement for each period that an income statement is required to be filed. The Company will reflect the requirements of this release in its unaudited condensed consolidated financial statements for the period ending March 31, 2019.

In August 2017, the FASB issued ASU No. 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities.” This ASU amends and simplifies existing guidance in order to allow companies to more accurately present the economic effects of risk management activities in the financial statements. ASU No. 2017-12 is effective for periods beginning after December 15, 2019, and earlier adoption is permitted. The Company adopted this ASU effective January 1, 2018 and the Company reclassified a $3.9 million unrealized gain, net of tax, from retained earnings to accumulated other comprehensive loss upon adoption.

In March 2017, the FASB issued ASU No. 2017-07, “Compensation – Retirement Benefits (Topic 715)”, in order to improve the presentation of net periodic pension and postretirement costs. The amendment requires that components of net benefit cost other than service cost are presented in the income statement outside a subtotal of income from operations. As a practical expedient, the Company has used the amounts disclosed in its pension and post-retirement benefits footnote as the estimation basis for applying the retrospective presentation requirements. The Company adopted this ASU effective January 1, 2018, and for retrospective presentation, reclassified $0.7 and $1.7 million from cost of goods sold and $0.8 and $0.9 million from selling, general and administrative expenses to other income, net for the years ended December 31, 2017 and 2016, respectively. In addition, the Company moved the amounts for loss on pension settlements for the years ended December 31, 2017 and 2016 out of operating profit to a line after the subtotal for operating profit.

In January 2017, the FASB issued ASU No. 2017-04, “Simplifying the Test for Goodwill Impairment (Topic 350).” The update is intended to simplify how an entity is required to test goodwill for impairment by comparing the implied fair value of a reporting unit's goodwill with the carrying amount of that goodwill. The Company adopted this ASU effective January 1, 2018.

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. The standard is effective January 1, 2019 and measurement and presentation of expenses will depend on classification as a finance or operating lease. In July 2018, the FASB issued ASU No. 2018-11, “Leases (Topic 842): Targeted Improvements,” which provides clarifications and improvements to ASU 2016-02, including options related to the transition method. The selected transition method enables entities to apply the transition requirements in this ASU as of January 1, 2019 rather than at the beginning of the earliest comparative period presented. The effect of initially applying the standard will be recognized as a cumulative-effect adjustment to retained earnings as of January 1, 2019 and is not expected to be material. The Company will adopt ASU 2016-02 effective January 1, 2019 using the modified retrospective approach with no restatement of comparative periods presented.

The Company has substantially completed its analysis of all of its leases and has identified changes to our business processes, systems and controls to support adoption of the new standard. The Company elected a suite of practical expedients, including retaining its current classification of leases, separating lease and non-lease components for certain asset classes and excluding leases expiring within twelve months. As a result, the Company anticipates that the initial impact of adopting this new standard on its consolidated statement of operations and consolidated statement of cash flows will not be material. The Company estimates a present value of approximately $115 million to $130 million of right-to-use assets and lease liabilities will be recognized in the consolidated balance sheet upon adoption.

Plant Closures and Discontinued Operations

12 Months Ended

Dec. 31, 2018

Discontinued Operations And Disposal Groups [Abstract]

Plant Closures and Discontinued Operations

4. Plant Closures and Discontinued Operations

Over the past four years, the Company has been restructuring its Carbon Materials and Chemicals (“CMC”) segment in order to concentrate its facilities in regions where the Company believes it holds key competitive advantages to better serve its global customers. These closure activities include:

	•	The cessation of naphthalene refining activities at the Company’s Follansbee, West Virginia coal tar distillation facility in the fourth quarter of 2018 subsequent to the commissioning of a new naphthalene refining plant in Stickney, Illinois.
	•	In September 2018, the Company sold its UK-based specialty chemicals business and recognized a loss on the transaction during the third quarter of 2018, which is included in Loss (gain) on sale of assets on the Consolidated Statement of Operations.

•

In November 2016, the Company sold its 30-percent interest in Tangshan Kailuan Koppers Carbon Chemical Company Limited (“TKK”) located in the Hebei Province in China.

•

In July 2016, the Company discontinued coal tar distillation activities at its CMC plant located in Clairton, Pennsylvania. In October 2018, the Company sold the facility and recognized a loss on the transaction during the fourth quarter of 2018, which is included in Loss (gain) on sale of assets in the consolidated statement of operations. As part of the transaction, the Company transferred cash to the buyer and the buyer assumed decommissioning, demolition and site restoration responsibilities.

•

In March 2016, the Company discontinued production at its 60-percent owned CMC plant located in Tangshan, China.

•

In February 2016, the Company ceased coal tar distillation and specialty pitch operations at both of its United Kingdom CMC facilities. In July 2016, the Company sold substantially all of its CMC 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.

•

In April 2014, the Company ceased its coal tar distillation activities at its CMC facility located in Uithoorn, the Netherlands.

Other closure and divestiture activity relates to the Company’s Railroad Utility Products and Services (“RUPS”) segment. These actions include:

•

In October 2016, the Company agreed to a long-term lease of its wood treatment facility in Houston, Texas to a third party.

•

In August 2015, the Company closed its RUPS plant located in Green Spring, West Virginia.

	•	In July 2015, the Company sold the assets of its 50-percent interest in KSA Limited Partnership, a concrete crosstie manufacturer.

In addition, in 2011, the Company ceased carbon black production at its CMC facility located in Kurnell, Australia. Costs associated with this closure are included in income (loss) from discontinued operations on the consolidated statement of operations and comprehensive (loss) income.

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, 2016	$	1.4		$	1.5		$	10.0		$	3.2		$	16.1
Accrual		0.9			2.1			4.7			6.9			14.6
Costs charged against assets		0.0			0.0			0.0			(6.3	)		(6.3	)
Reversal of accrued charges		(0.3	)		0.0			(1.8	)		0.0			(2.1	)
Cash paid		(0.3	)		(1.1	)		(2.4	)		(1.0	)		(4.8	)
Currency translation		0.0			0.2			0.1			0.5			0.8
Reserve at December 31, 2017	$	1.7		$	2.7		$	10.6		$	3.3		$	18.3
Accrual		0.0			0.9			1.8			2.2			4.9
Costs charged against assets		0.0			0.0			0.0			(2.1	)		(2.1	)
Reversal of accrued charges		0.0			0.0			(0.9	)		0.0			(0.9	)
Cash paid		0.0			(3.4	)		(7.9	)		(0.5	)		(11.8	)
Currency translation		0.0			(0.2	)		0.0			(0.1	)		(0.3	)
Reserve at December 31, 2018	$	1.7		$	0.0		$	3.6		$	2.8		$	8.1

Acquisitions

12 Months Ended

Dec. 31, 2018

Business Combinations [Abstract]

Acquisitions

5. Acquisitions

On April 10, 2018, Koppers Inc. acquired Cox Industries, Inc. (“Cox”) for net cash consideration of $201.3 million. The transaction was funded by borrowings on Koppers Inc.’s revolving credit facility discussed in “Note 16 - Debt.” Cox was renamed Koppers Utility and Industrial Products Inc. (“UIP”) subsequent to the acquisition. UIP is a manufacturer of treated wood transmission and distribution poles for utility companies and cooperative utility companies. It is also a manufacturer of treated wood pilings used for construction and marine applications. UIP manufactures and sells its treated wood poles and pilings through a network of eight manufacturing facilities and 19 distribution yards located throughout the United States. UIP treats its products with a variety of wood protection chemicals, including chromated copper arsenate and creosote, which are produced by the Company’s PC and CMC segments, respectively. UIP had revenues of approximately $147 million for the year ended December 31, 2017. Revenue from UIP included in our results for the year ended December 31, 2018 totaled $142 million.

On February 28, 2018, Koppers Inc. acquired M.A. Energy Resources, LLC (“MAER”) for net cash consideration of $62.8 million. The purchase price was funded by borrowings on Koppers Inc.’s revolving credit facility. MAER was renamed Koppers Recovery Resources LLC (“KRR”) subsequent to the acquisition. KRR is a vertically-integrated company that provides material recovery services for crossties that have been taken out of service and other biomass material. KRR converts this recovered material into alternative fuels, such as crosstie-derived fuel or biomass-derived fuel, that is used as a substitute for conventional higher-cost carbon-based fuel. KRR currently operates two processing facilities, each of which is located to serve its Class I railroad customer base. KRR had revenues of approximately $30 million for the year ended December 31, 2017. Revenue from KRR included in our results for the year ended December 31, 2018 totaled $21 million.

The valuation of identifiable assets acquired and liabilities assumed upon the acquisition of UIP and KRR are shown in the table below:

	UIP		KRR
(Dollars in millions)
Cash and cash equivalents	$	1.5	$	3.2
Accounts receivable		20.2		4.9
Inventory		43.1		0.0
Other current assets		1.2		0.3
Property, plant and equipment		19.6		6.6
Intangible assets, net		59.4		19.3
Goodwill		77.1		34.0
Other non-current assets		0.2		0.0
Total assets acquired		222.3		68.3
Accounts payable and accrued liabilities		18.7		2.3
Other non-current liabilities		0.8		0.0
Net assets acquired	$	202.8	$	66.0

Goodwill for both acquisitions has been allocated to the Company’s RUPS segment. The Company expects the goodwill recognized will be deductible for tax purposes. Recognized goodwill is attributable to the assembled workforce, expected synergies and other intangible assets that do not qualify for separate recognition. Net assets acquired include identifiable intangible assets with respect to customer contracts, non-compete agreements and trademarks as summarized in the following tables:

			UIP
(Dollars in millions)	Amount		Remaining Life
Customer contracts	$	58.2	15 years
Non-compete agreements		1.2	5 years
Total UIP	$	59.4

			KRR
(Dollars in millions)	Amount		Remaining Life
Customer contracts	$	18.7	15 years
Trademarks		0.6	2 years
Total KRR	$	19.3

Combined acquisition costs related to these two transactions were $6.5 million for year ended December 31, 2018 and are recorded within selling, general and administrative expenses in the consolidated statement of operations for the year ended December 31, 2018. Combined net sales of $163.0 million and loss before taxes of $4.2 million, including $6.0 million of inventory fair value purchase price accounting adjustments, was attributable to UIP and KRR and was included in the consolidated statement of operations for the year ended December 31, 2018.

The following unaudited pro forma information presents a summary of the Company’s revenues and income from continuing operations as if the UIP acquisition occurred on January 1, 2017 (the first day of the most recently completed fiscal year). The unaudited pro forma information is not necessarily indicative of operating results that would have been achieved had the acquisition been completed as of January 1, 2017 and is not intended to project the future financial results of the Company after the acquisition. The unaudited pro forma information is based on certain assumptions, which management believes are reasonable, and does not reflect the cost of any integration activities or the benefits from the acquisition and synergies that may be derived from any integration activities.

	Year Ended December 31,
	2018		2017
(Dollars in millions)
Pro forma revenue	$	1,760.9	$	1,622.5
Pro forma income from continuing operations attributable to Koppers		29.0		26.6
Pro forma income per share - continuing operations:
Basic -	$	1.39	$	1.28
Diluted -	$	1.36	$	1.21

Revenue Recognition

12 Months Ended

Dec. 31, 2018

Revenue From Contract With Customer [Abstract]

Revenue Recognition

6. Revenue Recognition

Effective January 1, 2018 the Company adopted ASC 606, Revenue from Contracts with Customers, using the modified retrospective method. The Company calculated the cumulative effect to the opening balance of retained earnings recognized at January 1, 2018 to be an increase of $0.3 million, consisting of $5.3 million in revenue and $5.0 million in cost of goods sold not previously recognized during the year ended December 31, 2017. Revenue and cost of goods sold recognized during the year ended December 31, 2018 from the adoption of Topic 606 was $3.1 million and $2.9 million, respectively, and, as such, the net impact of adopting Topic 606 for the year ended December 31, 2018 was a decrease in sales and cost of sales as follows:

	Year Ended December 31,
	2018
(Dollars in millions)
Sales	$	(2.2	)
Cost of sales		(2.1	)

Topic 606 impacted the timing of revenue recognized related to certain services to untreated cross-ties within the Company’s RUPS segment where those specific performance obligations were fulfilled prior to shipment and were historically not recognized as revenue until shipped. Refer to “Note 9 – Segment Information” for relevant disclosures regarding the disaggregation of revenue.

Contract Balances

The timing of revenue recognition and subsequent billings based on contractual terms and in accordance with Topic 606 results in both billed accounts receivable and unbilled receivables, both classified as accounts receivable, net of allowance within the consolidated balance sheet. In some instances, amounts are not billed at the time specific performance obligations are fulfilled, resulting in unbilled receivables or contract assets. Contract assets of $10.5 million and $5.3 million are recorded within accounts receivable, net of allowance within the consolidated balance sheet as of December 31, 2018 and January 1, 2018, respectively.

Earnings per Common Share

12 Months Ended

Dec. 31, 2018

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 is excluded from the computation of diluted loss per common share, if any.

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

	Year Ended December 31,
	2018		2017			2016
(Dollars in millions, except share amounts, in thousands, and per share amounts)
Net income attributable to Koppers	$	23.4	$	29.1		$	29.3
Income (loss) from discontinued operations		0.4		(0.8	)		0.6
Income from continuing operations attributable to Koppers	$	23.0	$	29.9		$	28.7
Weighted average common shares outstanding:
Basic		20,871		20,754			20,636
Effect of dilutive securities		455		1,246			419
Diluted		21,326		22,000			21,055
Earnings per common share – continuing operations:
Basic earnings per common share	$	1.10	$	1.44		$	1.39
Diluted earnings per common share		1.08		1.36			1.36
Other data:
Antidilutive securities excluded from computation of diluted earnings per common share		401		156			415

Stock-based Compensation

12 Months Ended

Dec. 31, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-based Compensation

8. Stock-based Compensation

The Company has outstanding stock-based compensation awards that were granted under the amended and restated 2005 Long-Term Incentive Plan (the “2005 LTIP”) and the 2018 Long-Term Incentive Plan (the “2018 LTIP”). Both the 2005 LTIP and the 2018 LTIP are collectively referred to as the ”LTIP”. On May 3, 2018, the 2018 LTIP was approved by our shareholders and the 2005 LTIP was frozen. Similar to the 2005 LTIP, the 2018 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 grants restricted stock units and performance stock units to certain employee participants (collectively, the “stock units”). For grants to most 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 employees in connection with employee compensation with vesting periods of two years or less.

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 have vesting 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 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 2015 exceeded the maximum value creation and vested at 200 percent in March 2018.

Performance stock units granted in 2016 and thereafter have vesting 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 relative to the Standard & Poor’s 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:

	May 2018 Grant			March 2018 Grant			March 2017 Grant			March 2016 Grant
Grant date price per share of performance award	$	39.10		$	41.60		$	44.10		$	18.11
Expected dividend yield per share		0.00	%		0.00	%		0.00	%		0.00	%
Expected volatility		39.40	%		39.40	%		43.50	%		40.86	%
Risk-free interest rate		2.35	%		2.38	%		1.54	%		0.96	%
Look-back period in years		2.84			2.84			2.83			2.84
Grant date fair value per share of performance award	$	44.29		$	47.12		$	64.02		$	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, 2018:

Performance Period

Minimum

Target

Maximum

2017 – 2019

110,262

220,524

2018 – 2020

128,093

256,186

Performance stock units for the 2016 – 2018 performance period will vest at 13 percent of the target share amount of 254,036 for participants who remain in service through the vesting date.

The following table shows a summary of the status and activity of non-vested stock awards for the year ended December 31, 2018:

	Restricted Stock Units			Performance Stock Units			Total Stock Units			Weighted Average Grant Date Fair Value per Unit
Non-vested at January 1, 2018		238,140			581,551			819,691		$	29.14
Granted		121,947			134,351			256,298		$	43.53
Performance share adjustment		0			(16,402	)		(16,402	)	$	24.85
Vested		(118,972	)		(409,732	)		(528,704	)	$	20.19
Forfeited		(17,554	)		(18,645	)		(36,199	)	$	37.80
Non-vested at December 31, 2018		223,561			271,123			494,684		$	45.65

Stock Options

Stock options to most executive officers vest and become exercisable in four equal annual installments. The stock options have a term of ten 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:

	May 2018 Grant			March 2018 Grant			March 2017 Grant			March 2016 Grant			March 2015 Grant
Grant date price per share of stock option award	$	39.10		$	41.60		$	44.10		$	18.11		$	17.57
Expected dividend yield per share		0.00	%		0.00	%		0.00	%		0.00	%		3.40	%
Expected life in years		5.73			5.73			5.77			5.96			5.75
Expected volatility		37.05	%		37.05	%		39.70	%		40.86	%		42.27	%
Risk-free interest rate		2.82	%		2.67	%		2.13	%		1.45	%		1.73	%
Grant date fair value per share of option awards	$	15.48		$	16.38		$	17.90		$	7.41		$	5.20

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 is based on historical exercise data of options previously granted by the Company. 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, 2018:

	Options			Weighted Average Exercise Price per Option		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in millions)
Outstanding at December 31, 2017		942,537		$	27.59
Granted		144,825		$	41.50
Exercised		(79,055	)	$	26.37
Forfeited		(26,367	)	$	31.67
Outstanding at December 31, 2018		981,940		$	29.63		5.80	$	0.00
Exercisable at December 31, 2018		642,092		$	29.03		4.50	$	0.00

Stock Compensation Expense

Total stock-based compensation expense recognized under the Company’s LTIP and employee stock purchase plan for the three years ended December 31, 2018 are as follows:

	Year Ended December 31,
	2018		2017		2016
(Dollars in millions)
Stock-based compensation expense recognized:
Selling, general and administrative expenses	$	12.5	$	10.6	$	8.9
Less related income tax benefit		3.1		4.1		3.6
Decrease in net income attributable to Koppers	$	9.4	$	6.5	$	5.3
Intrinsic value of exercised stock options	$	1.1	$	1.3	$	0.1
Cash received from the exercise of stock options	$	2.9	$	2.7	$	0.4

As of December 31, 2018, total future compensation expense related to non-vested stock-based compensation arrangements totaled $14.7 million and the weighted-average period over which this expense is expected to be recognized is approximately 25 months.

Segment Information

12 Months Ended

Dec. 31, 2018

Segment Reporting [Abstract]

Segment Information

9. Segment Information

The Company has three reportable segments: Railroad and Utility Products and Services, Performance Chemicals and Carbon Materials and Chemicals. The Company’s reportable segments contain multiple aggregated 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. The segment also operates a railroad services business that conducts engineering, design, repair and inspection services for railroad bridges and a business related to the recovery of used crossties. In April 2018, the Company acquired UIP, a manufacturer of treated wood utility transmission and distribution poles for utility companies and cooperative utility companies. It is also a manufacturer of treated wood pilings used for construction and marine applications. In February 2018, the Company acquired KRR, a vertically-integrated provider of crosstie recovery and disposal services. KRR converts recovered material into alternative fuels, such as crosstie-derived fuel or biomass-derived fuel, that is used as a substitute for conventional higher-cost carbon-based fuel.

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 used in the production of aluminum and 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 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 other (loss) income, interest expense, income taxes or operating costs of Koppers Holdings 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.

	Year Ended December 31,
	2018			2017			2016
(Dollars in millions)
Revenues from external customers:
Railroad and Utility Products and Services	$	634.8		$	512.6		$	586.5
Performance Chemicals		420.0			411.2			393.4
Carbon Materials and Chemicals		655.4			551.7			436.3
Total	$	1,710.2		$	1,475.5		$	1,416.2
Intersegment revenues:
Performance Chemicals	$	10.8		$	6.7		$	8.1
Carbon Materials and Chemicals		77.3			79.6			90.2
Total	$	88.1		$	86.3		$	98.3
Depreciation and amortization expense:
Railroad and Utility Products and Services	$	17.7		$	11.8		$	11.9
Performance Chemicals		17.8			17.9			18.7
Carbon Materials and Chemicals^(a)		15.3			20.1			22.3
Total	$	50.8		$	49.8		$	52.9
Operating profit (loss):
Railroad and Utility Products and Services^(b)	$	5.9		$	26.2		$	54.1
Performance Chemicals		36.2			71.4			63.5
Carbon Materials and Chemicals^(c)		70.7			28.0			(22.6	)
Corporate^(d)		(2.4	)		(2.0	)		(1.6	)
Total	$	110.4		$	123.6		$	93.4
Capital expenditures (excluding acquisitions):
Railroad and Utility Products and Services	$	19.2		$	10.6		$	11.2
Performance Chemicals		15.1			15.4			7.9
Carbon Materials and Chemicals		73.5			39.7			29.5
Corporate		1.9			1.8			1.3
Total	$	109.7		$	67.5		$	49.9

(a)	Excludes impairment charges of $3.7 million and $3.5 million in 2017 and 2016, respectively, for CMC.

(b)

Includes $6.0 million of inventory fair value purchase price accounting adjustments from our acquisition of UIP in 2018. Includes asset retirement obligation and other restructuring costs of $1.6 million for the restructuring of two facilities in the United States in 2017. Includes asset retirement obligation and other restructuring costs of $6.9 million for the restructuring of three facilities in the United States in 2016.

(c)	Includes plant closure costs of $3.9 million, $14.6 million and $13.2 million in 2018, 2017 and 2016, respectively, for CMC.

(d)	Operating loss for Corporate includes costs for Koppers Holdings Inc., the parent company of Koppers Inc., and acquisition-related 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,
	2018		2017
(Dollars in millions)
Segment assets:
Railroad and Utility Products and Services	$	538.0	$	249.7
Performance Chemicals		446.9		494.0
Carbon Materials and Chemicals		457.1		414.2
Segment assets		1,442.0		1,157.9
Cash and cash equivalents		2.1		0.7
Income tax receivable		2.8		1.7
Deferred taxes		20.5		29.4
Property, plant and equipment, net		6.0		5.2
Prepaid insurance and other assets		6.5		5.3
Total	$	1,479.9	$	1,200.2
Goodwill:
Railroad and Utility Products and Services	$	121.1	$	10.5
Performance Chemicals		175.4		177.7
Total	$	296.5	$	188.2

Revenues and Long-lived Assets by Geographic Area

	Year		Revenue		Long-lived assets
(Dollars in millions)
United States		2018	$	993.5	$	732.1
		2017		852.2		479.5
		2016		929.3		446.6
Australasia		2018		365.4		128.8
		2017		312.8		131.4
		2016		228.4		124.3
Europe		2018		214.6		44.8
		2017		173.1		44.8
		2016		140.2		31.9
Other countries		2018		136.7		18.3
		2017		137.4		19.4
		2016		118.3		19.5
Total		2018	$	1,710.2	$	924.1
		2017	$	1,475.5	$	675.1
		2016	$	1,416.2	$	622.3

Revenues by geographic area in the above table are attributed by the destination country of the sale. Revenues from non-U.S. countries totaled $716.6 million in 2018, $623.3 million in 2017 and $486.9 million in 2016.

Segment Revenues for Significant Product Lines

	Year Ended December 31,
	2018		2017		2016
(Dollars in millions)
Railroad and Utility Products and Services:
Railroad treated products	$	341.7	$	380.4	$	435.9
Utility poles		184.7		46.0		42.1
Rail joints		33.5		28.2		24.4
Railroad infrastructure services		36.9		34.8		43.4
Other products		38.0		23.2		40.7
		634.8		512.6		586.5
Performance Chemicals:
Wood preservative products		371.4		383.8		365.5
Other products		48.7		27.4		27.9
		420.0		411.2		393.4
Carbon Materials and Chemicals:
Pitch and related products		403.1		275.8		232.9
Creosote and distillates		84.1		83.7		73.2
Phthalic anhydride and other chemicals		84.6		89.8		73.3
Naphthalene		40.8		38.9		32.1
Other products		42.8		63.5		24.8
		655.4		551.7		436.3
Total	$	1,710.2	$	1,475.5	$	1,416.2

Income Taxes

12 Months Ended

Dec. 31, 2018

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,
	2018			2017			2016
(Dollars in millions)
Current:
Federal	$	(1.2	)	$	11.1		$	(1.9	)
State		0.1			0.6			1.3
Foreign		18.0			15.7			13.3
Total current tax provision		16.9			27.4			12.7
Deferred:
Federal		9.6			2.6			(1.6	)
State		(0.2	)		(1.2	)		0.5
Foreign		(0.3	)		0.2			(0.2	)
Total deferred tax provision (benefit)		9.1			1.6			(1.3	)
Total income tax provision	$	26.0		$	29.0		$	11.4

Income before income taxes for 2018, 2017 and 2016 included $106.1 million, $81.6 million and $48.2 million, respectively, from foreign operations.

On December 22, 2017, the Tax Cut and Jobs Act (“Tax Act”) was signed into law. The Tax Act significantly revised the U.S. corporate income tax system with changes that are effective in 2017 and 2018. The Tax Act lowered the U.S. corporate income tax rate to 21 percent from 35 percent and imposed a one-time transition tax on certain unrepatriated earnings of foreign subsidiaries. Changes in tax rates and tax laws and their impact on deferred taxes are accounted for in the period of legislative enactment.

The Company recorded income tax expense of $21.7 million for this one-time transition tax. In its December 31, 2017 income tax provision, the Company provisionally recorded income tax expense of $13.1 million. In 2018, the Company revised its original estimate and recorded additional income tax expense as a result of additional guidance issued by the IRS. Due to the availability of net operating losses, the Company’s cash payment for this one-time transition tax is approximately $5.1 million. The Company elected to pay this amount in pre-defined installments through 2024.

Deferred tax assets and liabilities are measured using enacted tax rates that are expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. In 2017, as a result of the U.S. corporate income tax rate reduction, the Company recorded a charge of $7.4 million to adjust the carrying value of its net deferred tax assets in the U.S. After further analysis and after the effect of filing its 2017 U.S. tax return, the Company revised this amount in 2018 and recorded an income tax benefit of $3.8 million.

The Tax Act introduced a new provision effective in 2018 that imposes a minimum tax on earnings of a foreign corporation that are deemed to exceed a certain threshold return relative to the underlying business investment. These earnings are referred to as global intangible low-taxed income (“GILTI”). The Company has included $6.6 million of income tax expense in its 2018 provision for the GILTI provision, net of foreign tax credits, which will not result in any cash tax payments since it is offset by net operating losses.

The Tax Act introduced a new provision that limits the amount of interest expense that can be deducted. Beginning in 2018, interest expense in excess of 30 percent of a taxpayer’s adjusted taxable income cannot be deducted. However, any interest expense that is disallowed in the current year can be carried forward to future years. The Company has concluded that, in the foreseeable future, it will not be able to benefit from the disallowed interest expense deduction. Therefore, a valuation allowance of $9.0 million has been recorded to offset this deferred tax asset.

The Tax Act introduces other new provisions that were effective for 2018 and changes how certain provisions are calculated beginning in 2018. Other than the GILTI provision and the interest expense limitation, the Company does not expect that any other new provisions or changes will have a material impact to its income tax provision.

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

	Year Ended December 31,
	2018			2017			2016
Federal income tax rate		21.0	%		35.0	%		35.0	%
State income taxes, net of federal tax benefit		(3.4	)		(1.6	)		(0.8	)
Foreign earnings taxed at different rates		1.7			(21.6	)		(10.1	)
Valuation allowance adjustments		6.2			0.9			(1.9	)
Transition tax from Tax Act		15.5			21.7			0.0
GILTI inclusion, net of foreign tax credits		12.0			0.0			0.0
Deferred tax adjustments		2.3			0.0			(0.2	)
Change in tax contingency reserves		(2.0	)		2.2			6.5
Deferred tax adjustments from Tax Act		(6.8	)		12.3			0.0
Other		0.9			(0.8	)		1.1
		47.4	%		48.1	%		29.6	%

As a result of the Tax Act and the one-time mandatory transition tax, all previously unremitted earnings for which a U.S. deferred tax liability had not been accrued have now been subject to U.S. tax. At December 31, 2018, there was approximately $457 million of such unremitted earnings. Substantially all unremitted earnings will remain indefinitely invested in our foreign subsidiaries for the foreseeable future. In the event these earnings are remitted as a dividend, they could be subject to taxation based on currency gains or losses, state taxes, and foreign withholding taxes. The Company estimates that it will not incur significant additional taxes on those potential remittances.

Taxes Excluded from Net Income Attributable to Koppers

The amount of income tax (benefit) expense included in comprehensive (loss) income but excluded from net income attributable to Koppers relating primarily to adjustments to copper swap contracts is $(10.0) million, $3.5 million, and $8.0 million for the years ended December 31, 2018, 2017 and 2016, respectively.

The amount of income tax (benefit) expense included in comprehensive (loss) income but excluded from net income attributable to Koppers relating to adjustments to reflect the unfunded status of employee post-retirement benefit plans is $(0.2) million, $2.8 million, and $2.0 million for the years ended December 31, 2018, 2017 and 2016, 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,
	2018			2017
(Dollars in millions)
Deferred tax assets:
Tax credits	$	27.0		$	15.0
Reserves, including insurance, environmental and deferred revenue		20.2			14.3
Federal and state tax loss carryforwards, expiring from 2019 to 2038		18.5			21.2
Pension and other postretirement benefits obligations		11.1			10.8
Asset retirement obligations		8.8			11.9
Foreign tax loss carryforwards, expiring beginning in 2019		5.5			9.3
Accrued employee compensation		5.4			6.3
Loss on derivative contracts		2.1			0.0
Book/tax inventory accounting differences		1.9			1.5
Other		4.9			6.1
Valuation allowance		(59.9	)		(44.5	)
Total deferred tax assets		45.5			51.9
Deferred tax liabilities:
Tax over book depreciation and amortization		35.7			33.2
Gain on derivative contracts		0.0			7.0
Other		1.1			0.7
Total deferred tax liabilities		36.8			40.9
Net deferred tax assets	$	8.7		$	11.0

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:

	December 31,
	2018		2017
Federal foreign tax credits	$	25.7	$	13.8
State temporary differences, net operating losses and tax credits		21.1		18.7
Federal temporary differences		7.0		0.0
Foreign temporary differences, net operating losses and capital losses		6.1		12.0
Total valuation allowances	$	59.9	$	44.5

In addition to the valuation allowance recorded with respect to deferred tax assets associated with disallowed interest expense deductions, the Company released a valuation allowance of $5.5 million for a subsidiary in China that had accumulated net operating losses. The Company utilized these net operating loss carryforwards in 2018 to offset current earnings.

Management evaluated the ability to realize the deferred tax assets that are related to our domestic operations, particularly in light of the Company’s domestic financial reporting losses. In assessing the need for a valuation allowance, management considered all positive and negative evidence related to the realization of the Company’s net deferred tax assets. The Company believes that it will be in a taxable income position in the foreseeable future due to certain provisions of the Tax Act and it will have sufficient taxable income to utilize deferred tax assets related to its domestic operations.

Unrecognized Tax Benefits

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

	December 31,
	2018			2017			2016
(Dollars in millions)
Balance at beginning of year	$	8.7		$	9.7		$	7.7
Additions based on tax provisions related to the current year		0.1			0.1			0.9
Additions for tax provisions of prior years		0.0			2.7			1.5
Reductions of tax provisions of prior years		(1.5	)		(3.4	)		0.0
Reductions resulting from a lapse in the statute of limitations		(0.3	)		(0.4	)		(0.4	)
Balance at end of year	$	7.0		$	8.7		$	9.7

As of December 31, 2018 and 2017, the total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate, was approximately $3.7 million and $4.4 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, 2018, 2017, and 2016, the Company recognized $(1.4) million, $(0.6) million and $1.2 million, respectively, in interest and penalties. As of December 31, 2018 and 2017, the Company had accrued interest and penalties of approximately $2.2 million and $3.6 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 $3.5 million due to the expirations of certain 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 the 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 2014.

Inventories

12 Months Ended

Dec. 31, 2018

Inventory Disclosure [Abstract]

Inventories

11. Inventories

Inventories as of December 31, 2018 and 2017 were as follows:

	December 31,
	2018		2017
(Dollars in millions)
Raw materials	$	199.5	$	173.6
Work in process		16.0		11.2
Finished goods		128.1		98.4
		343.6		283.2
Less revaluation to LIFO		58.9		46.3
Net	$	284.7	$	236.9

Fair Value Measurements

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Fair Value Measurements

12. Fair Value Measurements

Carrying amounts and the related estimated fair values of the Company’s financial instruments as of December 31, 2018 and 2017 are as follows:

	December 31, 2018				December 31, 2017
	Fair Value		Carrying Value		Fair Value		Carrying Value
(Dollars in millions)
Financial assets:
Cash and cash equivalents, including restricted cash	$	40.6	$	40.6	$	60.3	$	60.3
Investments and other assets		1.2		1.2		1.1		1.1
Financial liabilities:
Long-term debt (including current portion)	$	945.3	$	1,002.6	$	706.9	$	688.7

Cash and cash equivalents – The carrying value 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 issuances or on the current rates offered to the Company for debt of the same remaining maturities (Level 2). The fair value of the Company’s Revolving Credit Facility approximates carrying value due to the variable rate nature of this instrument.

Property, Plant and Equipment

12 Months Ended

Dec. 31, 2018

Property Plant And Equipment [Abstract]

Property, Plant and Equipment

13. Property, Plant and Equipment

Property, plant and equipment as of December 31, 2018 and 2017 were as follows:

	December 31,
	2018		2017
(Dollars in millions)
Land	$	17.5	$	17.6
Buildings		65.1		63.4
Machinery and equipment		800.9		756.6
		883.5	$	837.6
Less accumulated depreciation		465.6		509.6
Net	$	417.9	$	328.0

Depreciation expense, including impairment charges, for the years ended December 31, 2018, 2017 and 2016 amounted to $31.6 million, $37.5 million and $41.6 million, respectively.

Impairments – The Company did not incur impairment charges in 2018. Impairment charges for 2017 and 2016 were $3.7 million and $3.5 million, respectively. In 2017 and 2016, impairment charges primarily related to the decision to discontinue naphthalene and coal tar distillation activities at CMC plants located in the United States.

Goodwill and Other Identifiable Intangible Assets

12 Months Ended

Dec. 31, 2018

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, 2018 and December 31, 2017 was as follows:

	Railroad and Utility Products and Services			Performance Chemicals			Total
(Dollars in millions)
Balance at December 31, 2016	$	9.9		$	176.5		$	186.4
Currency translation		0.6			1.2			1.8
Balance at December 31, 2017	$	10.5		$	177.7		$	188.2
Acquisitions		111.1			0.0			111.1
Currency translation		(0.5	)		(2.3	)		(2.8	)
Balance at December 31, 2018	$	121.1		$	175.4		$	296.5

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 quarters of 2018 and 2017, the Company determined that the estimated fair values exceeded the carrying values of all the reporting units, and accordingly, there was no impairment of goodwill for the year ended December 31, 2018 and 2017, respectively.

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

					December 31,
					2018						2017
	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			12.3	$	228.8	$	56.5	$	172.3	$	154.7	$	43.9	$	110.8
Technology	4 to 12			4.0		26.7		16.2		10.5		26.8		12.5		14.3
Trademarks	2 to 17			4.0		7.6		3.5		4.1		6.5		2.7		3.8
Supply contracts		10		2.2		2.4		2.1		0.3		2.5		2.0		0.5
Non-compete agreements		12		6.8		1.6		0.8		0.8		1.4		1.2		0.2
Favorable lease agreements		3		0.0		0.7		0.7		0.0		0.7		0.7		0.0
Total				11.1	$	267.8	$	79.8	$	188.0	$	192.6	$	63.0	$	129.6

In 2018, the gross carrying value of identifiable intangible assets increased by $75.2 million. Total amortization expense related to these identifiable intangible assets was $19.2 million, $14.6 million and $14.8 million for the years ended December 31, 2018, 2017 and 2016, respectively. Estimated amortization expense for the next five years is summarized below:

	Estimated annual amortization
(Dollars in millions)
2019	$	20.3
2020		19.3
2021		17.3
2022		14.5
2023		13.0

Pensions and Post-Retirement Benefit Plans

12 Months Ended

Dec. 31, 2018

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 and two of the non-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 2017, the Company offered a cash lump sum or annuity buyout to its terminated deferred vested participants and completed an irrevocable transaction with an insurance company to annuitize approximately $31.3 million of retiree pension obligations for a selected group of retirees in its U.S. qualified defined benefit pension plan. The Company recorded a pension settlement charge of $10.0 million related to these two transactions.

In 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 and recorded a pension settlement charge of $4.4 million.

Expense related to defined contribution plans totaled $7.5 million, $8.9 million and $7.8 million for the years ended December 31, 2018, 2017 and 2016, respectively.

Net periodic pension costs for 2018, 2017 and 2016 were as follows:

	Year Ended December 31,
	Pension Benefits									Other Benefits
	2018			2017			2016			2018		2017			2016
(Dollars in millions)
Service cost	$	1.9		$	2.0		$	1.7		$	0.1	$	0.1		$	0.1
Interest cost		7.5			9.0			11.0			0.4		0.4			0.4
Expected return on plan assets		(8.5	)		(9.6	)		(10.5	)		0.0		0.0			0.0
Amortization of net loss (gain)		1.4			1.9			2.2			0.0		(0.2	)		(0.4	)
Settlements and curtailments		0.0			10.0			4.4			0.0		0.0			0.0
Net periodic benefit cost	$	2.3		$	13.3		$	8.8		$	0.5	$	0.3		$	0.1

The change in the funded status of the pension and postretirement plans as of December 31, 2018 and December 31, 2017 is as follows:

	Year Ended December 31,
	Pension Benefits						Other Benefits
	2018			2017			2018			2017
(Dollars in millions)
Change in benefit obligation:
Benefit obligation at beginning of year	$	219.1		$	243.6		$	11.1		$	10.0
Service cost		1.9			2.0			0.1			0.1
Interest cost		7.5			9.0			0.4			0.4
Actuarial (gains) losses		(13.2	)		7.3			(1.7	)		1.5
Plan amendments		0.7			0.0			0.0			0.0
Settlements		0.0			(36.9	)		0.0			0.0
Currency translation		(3.5	)		5.5			0.0			0.0
Benefits paid		(10.8	)		(11.4	)		(0.5	)		(0.9	)
Benefit obligation at end of year		201.7			219.1			9.4			11.1
Change in plan assets:
Fair value of plan assets at beginning of year		188.8			200.9			0.0			0.0
Actual return on plan assets		(8.6	)		19.5			0.0			0.0
Employer contribution		4.2			11.2			0.5			0.9
Settlements		0.0			(36.9	)		0.0			0.0
Currency translation		(4.0	)		5.5			0.0			0.0
Benefits paid		(10.8	)		(11.4	)		(0.5	)		(0.9	)
Fair value of plan assets at end of year		169.6			188.8			0.0			0.0
Funded status of the plan	$	(32.1	)	$	(30.3	)	$	(9.4	)	$	(11.1	)

In 2018, the net actuarial gain of $13.2 million is due principally to the increase in the discount rate used to measure the benefit obligation as of December 31, 2018 compared to the prior year.

Plan Data

	Year Ended December 31,
	Pension Benefits				Other Benefits
	2018		2017		2018		2017
(Dollars in millions)
Amounts recognized in the balance sheet consist of:
Noncurrent assets	$	8.9	$	7.0	$	0.0	$	0.0
Current liabilities		1.2		1.1		1.0		1.0
Noncurrent liabilities		39.8		36.2		8.4		10.1
Pension plans with projected benefit obligations in excess of plan assets:
Benefit obligation	$	148.6	$	159.9
Fair value of plan assets		107.7		122.6
Pension plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligation	$	148.4	$	159.6
Fair value of plan assets		107.7		122.6

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, 2018 and 2017 was $201.3 million and $218.7 million, respectively.

Expected Contributions for the 2019 Fiscal Year

The expected contributions by the Company for 2019 are estimated to be $2.7 million for pension plans and $0.9 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)
2019	$	11.2	$	0.9
2020		11.1		0.9
2021		11.3		0.7
2022		11.5		0.7
2023		11.6		0.6
Next five years		64.0		2.9

Weighted-Average Assumptions as of December 31

	December 31,
	Pension Benefits						Other Benefits
	2018			2017			2018			2017
Discount rate		4.03	%		3.51	%		4.45	%		3.88	%
Expected return on plan assets		4.83			4.62
Rate of compensation increase		3.41			3.50
Initial medical trend rate								5.90			6.10

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,
	2018			2017
Debt securities		72	%		64	%
Equity securities		24			30
Other		4			6
		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.

All 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, 2018 and December 31, 2017:

	As of December 31, 2018
	Quoted prices in active markets for identical assets (Level 1)		Significant observable inputs (Level 2)		Significant unobservable inputs (Level 3)		Total
(Dollars in millions)
U.S. equity securities	$	12.3	$	9.7	$	0.0	$	22.0
International equity securities		14.2		5.2		0.0		19.4
U.S. debt securities		34.3		39.0		0.0		73.3
International debt securities		5.3		43.1		0.0		48.4
Real estate and other investments		0.0		1.3		3.2		4.5
Cash and cash equivalents		0.0		2.0		0.0		2.0
	$	66.1	$	100.3	$	3.2	$	169.6

	As of December 31, 2017
	Quoted prices in active markets for identical assets (Level 1)		Significant observable inputs (Level 2)		Significant unobservable inputs (Level 3)		Total
(Dollars in millions)
U.S. equity securities	$	18.6	$	12.7	$	0.0	$	31.3
International equity securities		15.0		10.2		0.0	25.2
U.S. debt securities	21.4			53.0		2.5	76.9
International debt securities		7.5	34.8			1.0	43.3
Real estate and other investments	0.5		0.8			8.3	9.6
Cash and cash equivalents		0.0	2.5			0.0	2.5
	$	63.0	$	114.0	$	11.8	$	188.8

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, 2018:

	As of December 31, 2018
	Other Investments			Debt Securities
(Dollars in millions)
Balance at beginning of year	$	8.3		$	3.5
Purchases, sales, issuances and settlements		(4.3	)		(3.4	)
Realized and unrealized gains		(0.8	)		(0.1	)
Balance at the end of year	$	3.2		$	0.0
The amount of total losses during the period attributable to the change in unrealized losses relating to Level 3 net assets still held at the reporting date	$	(0.1	)	$	0.0

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 $10.3 million in 2018, $11.2 million in 2017 and $10.4 million in 2016.

Debt

12 Months Ended

Dec. 31, 2018

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Debt

16. Debt

Debt as of December 31, 2018 and 2017 was as follows:

					December 31,
	Weighted Average Interest Rate			Maturity	2018		2017
Term Loan		5.65	%	2023	$	92.5	$	0.0
Revolving Credit Facility		5.65	%	2023		390.0		155.0
Construction and other loans		4.59	%	2020		20.1		33.7
Senior Notes due 2025		6.00	%	2025		500.0		500.0
Total debt						1,002.6		688.7
Less short-term debt and current maturities of long-term debt						11.6		11.4
Less unamortized debt issuance costs						12.2		11.7
Long-term debt					$	978.8	$	665.6

Senior Notes due 2025

The 2025 Notes are senior obligations, are unsecured and are guaranteed by Koppers Holdings Inc. and certain of Koppers Inc.’s domestic subsidiaries. The 2025 Notes pay interest semi-annually in arrears on February 15 and August 15 and will mature on February 15, 2025 unless earlier redeemed or repurchased. On or after February 15, 2020, the Company is entitled to redeem all or a portion of the 2025 Senior Notes at a redemption price of 104.5 percent of principal value, declining to a redemption price of 101.5 percent on or after February 15, 2022 until the redemption price is equivalent to the principal value on April 15, 2023.

The indenture governing the 2025 Senior Notes includes customary covenants that restrict, among other things, the ability of Koppers Inc. and its restricted subsidiaries to incur additional debt, pay dividends or make certain other restricted payments, incur liens, merge or sell all or substantially all of the assets of Koppers Inc. or its subsidiaries or enter into various transactions with affiliates.

Revolving Credit Facility

On April 10, 2018, the Company amended its $600 million Revolving Credit Facility to enter into a new Secured Term Loan Facility. The new Secured Term Loan Facility includes the $600 million Revolving Credit Facility and a secured term loan of $100 million with a quarterly amortization of $2.5 million and a five-year maturity. In addition, the maturity date of the amended Revolving Credit Facility was extended one year to April 2023. The interest rate on the amended Revolving Credit Facility is variable and is based on LIBOR.

Borrowings under the Revolving Credit Facility are 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 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, 2018, the Company had $179.0 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, 2018, $31.9 million of commitments were utilized by outstanding letters of credit.

Loss on Extinguishment of Debt

In February 2017, all of the outstanding Koppers Inc. senior notes due 2019 were repurchased at a premium to carrying value and accordingly, the Company realized a loss on extinguishment of debt totaling $10.0 million consisting of $7.3 million for bond premium and bond tender expenses and $2.7 million for the write-off of unamortized debt issuance costs.

Also in February 2017, Koppers Inc. repaid its term loan in full and entered into the Revolving Credit Facility. Accordingly, the Company realized a loss of $3.3 million for the write-off of unamortized debt issuance costs.

Construction Loan

The Company’s 75-percent owned subsidiary, Koppers (Jiangsu) Carbon Chemical Company Limited (“KJCC”) entered into a committed loan facility agreement with a third-party bank. Borrowings under the third-party bank facility, which includes a construction loan and a working capital facility, totaled $19.7 million at December 31, 2018 and are secured by a letter of credit issued by a bank under the Revolving Credit Facility. KJCC began repaying the construction loan portion of the third-party commitment, which requires semi-annual installments every six months starting in June 2018 with a final repayment in December 2020.

Debt Maturities and Deferred Financing Costs

At December 31, 2018 the aggregate debt maturities for the next five years are as follows:


(Dollars in millions)
2019	$	11.6
2020		28.4
2021		10.0
2022		452.6
2023		0.0
Thereafter		500.0
Total debt	$	1,002.6

Unamortized debt issuance costs (net of accumulated amortization of $4.2 million and $1.8 million at December 31, 2018 and 2017, respectively) were $12.2 million and $11.7 million at December 31, 2018 and 2017, respectively, and are included as a deduction from the carrying amount of long-term debt.

Leases

12 Months Ended

Dec. 31, 2018

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)
2019	$	30.3
2020		23.7
2021		18.3
2022		14.9
2023		10.9
Thereafter		36.0
Total	$	134.1

Operating lease expense for 2018, 2017 and 2016 was $49.4 million, $50.4 million and $50.3 million, respectively.

Derivative Financial Instruments

12 Months Ended

Dec. 31, 2018

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 2020. The Company enters into foreign currency forward contracts to manage foreign currency risk associated with the Company’s receivable and payable balances in addition to foreign-denominated sales. 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.

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. These amounts are classified in cost of sales in the consolidated statement of operations.

As of December 31, 2018 and December 31, 2017, the Company had outstanding copper swap contracts of the following amounts:

	Units Outstanding (in Pounds)			Net Fair Value - Asset (Liability)
	December 31,			December 31,
	2018		2017	2018			2017
(Amounts in millions)
Cash flow hedges		35.5	37.8	$	(6.8	)	$	25.5
Not designated as hedges		13.3	11.3		(2.4	)		4.5
Total		48.8	49.1	$	(9.2	)	$	30.0

As of December 31, 2018 and December 31, 2017, the fair value of the outstanding copper swap contracts is recorded in the balance sheet as follows:

	December 31,
	2018			2017
(Dollars in millions)
Other current assets	$	0.0		$	21.8
Other assets		0.0			8.2
Accrued liabilities		(9.0	)		0.0
Other long-term liabilities		(0.2	)		0.0
Net (liability) asset on balance sheet	$	(9.2	)	$	30.0
Accumulated other comprehensive (loss) gain, net of tax	$	(5.3	)	$	15.8

In the next twelve months the Company estimates that $4.0 million of unrealized losses, net of tax, related to commodity price hedging will be reclassified from other comprehensive (loss) income into earnings.

See the consolidated statement of comprehensive (loss) 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 years ended December 31, 2018 and 2017, the following amounts were recognized in earnings related to copper swap contracts:

	Year Ended December 31,
	2018			2017
(Dollars in millions)
Gain from ineffectiveness of cash flow hedges	$	0.0		$	5.6
(Loss) gain from contracts not designated as hedges		(6.9	)		3.5
Net	$	(6.9	)	$	9.1

The fair value associated with forward contracts related to foreign currency that are not designated as hedges are immediately charged to earnings. These amounts are classified in cost of sales in the consolidated statement of operations. As of December 31, 2018 and December 31, 2017, the fair value of outstanding foreign currency forward contracts is recorded in the balance sheet as follows:

	December 31,
	2018			2017
(Dollars in millions)
Other current assets	$	0.9		$	0.3
Accrued liabilities		(1.0	)		(0.2	)
Net (liability) asset on balance sheet	$	(0.1	)	$	0.1

As of December 31, 2018 and 2017, the net currency units outstanding were:

	December 31,
	2018		2017
(In millions)
British Pounds		GBP 5.7		GBP 7.0
New Zealand Dollars		NZD 16.0		NZD 15.5
United States Dollars		USD 6.0		USD 12.5
Canadian Dollars		CAD 0.0		CAD 2.5
Euro		EUR 1.2		EUR 0.0

Common Stock and Senior Convertible Preferred Stock

12 Months Ended

Dec. 31, 2018

Equity [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, 2018 are as follows:

	December 31,
	2018			2017			2016
(Shares in thousands)
Senior Convertible Preferred Stock:
Balance at beginning and end of year		0			0			0
Common Stock:
Balance at beginning of year		22,384			22,141			22,016
Issued for employee stock plans		645			243			125
Balance at end of year		23,029			22,384			22,141
Treasury Stock:
Balance at beginning of year		(1,606	)		(1,476	)		(1,459	)
Shares repurchased		(874	)		(130	)		(17	)
Balance at end of year		(2,480	)		(1,606	)		(1,476	)

Commitments and Contingent Liabilities

12 Months Ended

Dec. 31, 2018

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, 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 65 plaintiffs in 35 cases pending as of December 31, 2018, compared to 87 plaintiffs in 48 cases pending as of December 31, 2017. As of December 31, 2018, there were 34 cases pending in state court in Pennsylvania, and one case pending in state court in Tennessee.

The plaintiffs in all 35 pending cases seek to recover compensatory damages. Plaintiffs in 30 of those cases also seek to recover punitive damages. The plaintiffs in the 34 cases filed in Pennsylvania 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.

Pavement Sealer Cases. Koppers Inc. is one of seven defendants in separate federal lawsuits recently filed by nine municipalities in the state of Minnesota. These lawsuits were filed in December 2018 and January 2019 in federal district court in Minnesota. Each of the complaints allege that contamination caused by coal tar-based pavement sealer products has impacted their stormwater retention ponds resulting in substantially increased disposal costs when the ponds are periodically dredged. The plaintiffs seek to recover compensatory damages and other costs in addition to compelling the defendants to remove the alleged contamination from the plaintiffs’ stormwater retention ponds and other stormwater-management devices.

The Company has not provided a reserve for the coal tar pitch or pavement sealer 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.

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, 2018, amounts paid by Beazer East as a result of its environmental remediation obligations under the Indemnity have averaged, in total, approximately $11 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. On June 4, 2018, Koppers Inc. received a letter from the U.S. Environmental Protection Agency ("EPA") concerning potential violations of the Clean Water Act observed during inspections and review of Spill Prevention, Control and Countermeasure Plans and Facility Response Plans at the Company’s facilities in Follansbee, WV; Green Spring, WV; and Clairton, PA. In addition, the EPA reviewed one facility’s compliance with an earlier consent order regarding above ground storage tank integrity testing. The Company continues to meet and correspond with the EPA to discuss and present relevant information related to the allegations. The Company currently cannot estimate the potential penalties, fines or other expenditures, if any, that may result from any EPA actions relating to the alleged potential violations and, therefore, the Company cannot determine if the ultimate outcome of this matter will have a material impact on the Company's financial position, results of operations or cash flows.

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 a private 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 minimis contributor at the site.

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 private allocation process which is ongoing.

Additionally, the Company is involved in two separate natural resource damages assessments at the Portland Harbor site. An assessment is intended to identify damages to natural resources caused by the releases of hazardous substances to the Willamette River and to serve as the foundation to estimate liabilities for settlements of natural resource damages claims or litigation to recover from those who do not settle with the trustee groups. One of the natural resource damage assessments was filed in January 2017 by the Yakama Nation in Oregon federal court. Yakama Nation seeks recovery for future response costs and the costs of assessing injury to natural resources and recovery for past costs of overseeing investigations conducted on the site. The Yakama Nation case has been stayed by the court pending completion of the private allocation process for the Portland Harbor CERCLA site.

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 minimis 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 $2.2 million at December 31, 2018. 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.

There are two plant sites in the United States related to the Performance Chemicals business where the Company has recorded an environmental remediation liability for soil and groundwater contamination which occurred prior to the Company’s acquisition of the business. As of December 31, 2018, the Company’s estimated environmental remediation liability for these acquired sites totals $3.1 million.

There is one plant site in the United States related to the Utility and Industrial Products business where the Company has recorded an environmental remediation liability for soil and groundwater contamination which occurred prior to the Company’s acquisition of the business. As of December 31, 2018, the Company’s estimated environmental remediation liability for the acquired site totals $1.9 million.

Foreign Environmental Matters. There is one plant site related to the Performance Chemicals business located in Australia where the Company has recorded an environmental remediation liability for soil and groundwater contamination which occurred prior to the acquisition of the business. As of December 31, 2018, the Company’s estimated environmental remediation liability for the acquired site totals $1.5 million.

In December 2011, the Company ceased manufacturing operations at its Continental Carbon facility located in Kurnell, Australia. As of December 31, 2018, the Company believes it has fully satisfied all site remediation responsibilities resulting from the closure.

Environmental Reserves Rollforward. The following table reflects changes in the accrued liability for environmental matters, of which $3.5 million and $5.1 million are classified as current liabilities at December 31, 2018 and 2017:

	December 31,
	2018			2017
(Dollars in millions)
Balance at beginning of year	$	13.9		$	12.9
Expense		0.9			3.2
Revision of reserves		(2.4	)		(0.7	)
Cash expenditures		(3.8	)		(1.8	)
Acquisition		1.9			0.0
Currency translation		(0.4	)		0.3
Balance at end of period	$	10.1		$	13.9

Selected Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2018

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, 2018 and 2017:

	Year Ended December 31, 2018
	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	$	406.1	$	436.0	$	442.7	$	425.4		$	1,710.2
Operating profit		43.3		22.3		31.2		13.6			110.4
Income (loss) from continuing operations ^(a)		23.8		0.5		6.9		(2.4	)		28.8
Net income (loss) ^(a)		23.7		1.0		6.9		(2.4	)		29.2
Net income (loss) attributable to Koppers^(a)		17.8		0.6		7.6		(2.6	)		23.4
Common stock data:
Earnings (loss) per common share attributable to Koppers common shareholders: ^(a)(b)
Basic –
Continuing operations	$	0.86	$	0.01	$	0.36	$	(0.13	)	$	1.10
Discontinued operations		0.00		0.02		0.00		0.00			0.02
Earnings (loss) per basic common share	$	0.86	$	0.03	$	0.36	$	(0.13	)	$	1.12
Diluted –
Continuing operations	$	0.81	$	0.01	$	0.35	$	(0.13	)	$	1.08
Discontinued operations		0.00		0.02		0.00		0.00			0.02
Earnings (loss) per diluted common share	$	0.81	$	0.03	$	0.35	$	(0.13	)	$	1.10

	Year Ended December 31, 2017
	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	$	346.6	$	378.0		$	384.8	$	366.1		$	1,475.50
Operating profit ^(c)		28.1		38.1			43.8		13.6			123.6
Income (loss) from continuing operations		4.7		20.9			20.0		(14.3	)		31.3
Net income (loss)		4.6		19.8			19.9		(13.8	)		30.5
Net income (loss) attributable to Koppers		4.4		19.7			19.8		(14.8	)		29.1
Common stock data:
Earnings (loss) per common share attributable to Koppers common shareholders: ^(b)
Basic –
Continuing operations	$	0.21	$	1.00		$	0.96	$	(0.73	)	$	1.44
Discontinued operations		0.00		(0.06	)		0.00		0.02			(0.04	)
Earnings (loss) per basic common share	$	0.21	$	0.94		$	0.96	$	(0.71	)	$	1.40
Diluted –
Continuing operations	$	0.20	$	0.95		$	0.91	$	(0.73	)	$	1.36
Discontinued operations		0.00		(0.05	)		0.00		0.02			(0.04	)
Earnings (loss) per diluted common share	$	0.20	$	0.90		$	0.91	$	(0.71	)	$	1.32

(a) Income tax expense for the fourth quarter of 2017 was increased by $20.5 million due to the impact of the Tax Cuts and Jobs Act which was signed into law on December 22, 2017.

(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.

(c) Operating profit for the third quarter of 2017 was increased by $8.8 million due to the impact of reclassifying the loss on pension settlement to below the operating profit line item in connection with adopting ASU No. 2017-07, “Compensation – Retirement Benefits (Topic 715)” in 2018.

Subsidiary Guarantor Information for Koppers Inc. Shelf Registration

12 Months Ended

Dec. 31, 2018

Subsidiary Guarantor Information for Koppers Inc. Shelf Registration

22. Subsidiary Guarantor Information for Koppers Inc. Shelf Registration

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 supplemental indenture which the trustee and the issuing company would enter into concurrently 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. The Revolving 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. Revolving Credit Facility agreement provides for a revolving credit facility 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, 2018, Koppers Inc.’s assets exceeded its liabilities by $56.6 million. The amount of restricted net assets unavailable for distribution to Koppers Holdings Inc. by Koppers Inc. totals $36.8 million as of December 31, 2018. Cash dividends paid to Koppers Holdings Inc. by its subsidiaries totaled $31.8 million, $3.8 million and $1.2 million for the years ended December 31, 2018, 2017 and 2016, respectively.

Condensed Consolidating Statement of Comprehensive (Loss) Income

For the Year Ended December 31, 2018

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries		Consolidating Adjustments			Consolidated
(Dollars in millions)
Net sales	$	0.0		$	569.6		$	350.2		$	874.4	$	(84.0	)	$	1,710.2
Cost of sales including depreciation, amortization and restructuring		0.0			530.8			272.0			711.3		(84.2	)		1,429.9
Gain on sale of assets		0.0			6.2			0.0			2.1		0.0			8.3
Selling, general and administrative		2.4			52.2			46.4			60.6		0.0			161.6
Operating profit (loss)		(2.4	)		(19.6	)		31.8			100.4		0.2			110.4
Other income (loss)		0.0			(4.0	)		1.5			3.2		0.0			0.7
Equity income of subsidiaries		25.3			88.4			82.4			0.0		(196.1	)		0.0
Interest expense (income)		0.0			53.9			(0.1	)		2.5		0.0			56.3
Income taxes		(0.5	)		(14.4	)		24.0			16.9		0.0			26.0
Income (loss) from continuing operations		23.4			25.3			91.8			84.2		(195.9	)		28.8
Discontinued operations		0.0			0.0			0.0			0.4		0.0			0.4
Noncontrolling interests		0.0			0.0			0.0			5.8		0.0			5.8
Net income (loss) attributable to Koppers	$	23.4		$	25.3		$	91.8		$	78.8	$	(195.9	)	$	23.4
Comprehensive (loss) income attributable to Koppers	$	(27.4	)	$	(25.4	)	$	41.0		$	52.9	$	(68.5	)	$	(27.4	)

Condensed Consolidating Statement of Comprehensive (Loss) Income

For the Year Ended December 31, 2017

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries		Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Net sales	$	0.0		$	590.6		$	344.9	$	623.3		$	(83.3	)	$	1,475.5
Cost of sales including depreciation and amortization		0.0			570.2			235.0		496.3			(82.1	)		1,219.4
Selling, general and administrative		1.9			46.9			43.3		40.4			0.0			132.5
Operating profit (loss)		(1.9	)		(26.5	)		66.6		86.6			(1.2	)		123.6
Other income (loss)		0.0			(1.0	)		2.4		2.3			(1.2	)		2.5
Equity income of subsidiaries		30.3			103.8			64.7		0.0			(198.8	)		0.0
Interest expense		0.0			39.0			0.0		4.7			(1.2	)		42.5
Loss on pension settlement		0.0			10.0			0.0		0.0			0.0			10.0
Loss on extinguishment of debt		0.0			13.3			0.0		0.0			0.0			13.3
Income taxes		(0.7	)		(16.4	)		30.0		16.2			(0.1	)		29.0
Income (loss) from continuing operations		29.1			30.4			103.7		68.0			(199.9	)		31.3
Discontinued operations		0.0			0.0			0.0		(0.8	)		0.0			(0.8	)
Noncontrolling interests		0.0			0.0			0.0		1.4			0.0			1.4
Net income (loss) attributable to Koppers	$	29.1		$	30.4		$	103.7	$	65.8		$	(199.9	)	$	29.1
Comprehensive income (loss) attributable to Koppers	$	60.7		$	61.8		$	132.8	$	89.2		$	(283.8	)	$	60.7

Condensed Consolidating Statement of Comprehensive (Loss) Income

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			635.7			252.3		412.4			(101.2	)		1,199.2
Gain on sale of assets		0.0			0.0			0.0		(2.1	)		0.0			(2.1	)
Selling, general and administrative		1.9			42.4			38.2		43.2			0.0			125.7
Operating profit (loss)		(1.9	)		(17.4	)		60.1		51.2			1.4			93.4
Other income (loss)		0.0			(2.3	)		4.1		0.3			(1.8	)		0.3
Equity income of subsidiaries		30.6			79.1			35.9		0.0			(145.6	)		0.0
Interest expense		0.0			47.6			0.0		5.0			(1.8	)		50.8
Loss on pension settlement		0.0			4.4			0.0		0.0			0.0			4.4
Income taxes		(0.6	)		(23.2	)		22.2		13.0			0.0			11.4
Income (loss) 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 (loss) 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 Balance Sheet

December 31, 2018

	Parent		Koppers Inc.		Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries		Consolidating Adjustments			Consolidated
(Dollars in millions)
ASSETS
Cash and cash equivalents	$	0.0	$	2.1	$	0.0		$	38.5	$	0.0		$	40.6
Receivables, net		0.0		57.8		28.5			106.2		0.0			192.5
Affiliated receivables		0.5		69.2		16.6			3.1		(89.4	)		0.0
Inventories, net		0.0		105.6		30.2			150.8		(1.9	)		284.7
Other current assets		0.0		3.8		2.2			16.3		0.2			22.5
Total current assets		0.5		238.5		77.5			314.9		(91.1	)		540.3
Equity investments		55.7		984.4		333.1			0.0		(1,373.2	)		0.0
Property, plant and equipment, net		0.0		212.0		51.4			154.5		0.0			417.9
Goodwill		0.0		0.8		153.1			142.6		0.0			296.5
Intangible assets, net		0.0		6.5		86.5			95.0		0.0			188.0
Deferred tax assets		0.0		20.5		(7.3	)		2.3		0.0			15.5
Affiliated loan receivables		0.0		27.2		148.3			18.4		(193.9	)		0.0
Other assets		0.0		4.8		4.7			12.2		0.0			21.7
Total assets	$	56.2	$	1,494.7	$	847.3		$	739.9	$	(1,658.2	)	$	1,479.9
LIABILITIES AND EQUITY
Accounts payable	$	0.0	$	76.9	$	43.0		$	57.3	$	0.0		$	177.2
Affiliated payables		0.0		81.4		0.4			7.6		(89.4	)		0.0
Accrued liabilities		0.0		53.9		22.4			33.6		0.0			109.9
Current maturities of long-term debt		0.0		10.0		0.1			1.5		0.0			11.6
Total current liabilities		0.0		222.2		65.9			100.0		(89.4	)		298.7
Long-term debt		0.0		960.3		0.1			18.4		0.0			978.8
Affiliated debt		0.0		166.7		18.7			8.5		(193.9	)		0.0
Other long-term liabilities		0.0		88.9		8.6			37.9		0.0			135.4
Total liabilities		0.0		1,438.1		93.3			164.8		(283.3	)		1,412.9
Koppers shareholders’ equity		56.2		56.6		754.0			564.3		(1,374.9	)		56.2
Noncontrolling interests		0.0		0.0		0.0			10.8		0.0			10.8
Total liabilities and equity	$	56.2	$	1,494.7	$	847.3		$	739.9	$	(1,658.2	)	$	1,479.9

Condensed Consolidating Balance Sheet

December 31, 2017

	Parent		Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
ASSETS
Cash and cash equivalents	$	0.0	$	0.7		$	0.0		$	59.6		$	0.0		$	60.3
Receivables, net		0.0		48.6			27.7			84.6			0.0			160.9
Affiliated receivables		0.6		19.4			(83.0	)		(12.1	)		75.1			0.0
Inventories, net		0.0		80.4			40.5			117.9			(1.9	)		236.9
Deferred tax assets		0.0		0.0			0.0			(0.1	)		0.1			0.0
Other current assets		0.0		6.6			23.0			18.8			0.2			48.6
Total current assets		0.6		155.7			8.2			268.7			73.5			506.7
Equity investments		99.3		716.3			276.8			(0.1	)		(1,092.3	)		0.0
Property, plant and equipment, net		0.0		155.2			47.3			125.5			0.0			328.0
Goodwill		0.0		0.8			153.1			34.3			0.0			188.2
Intangible assets, net		0.0		7.2			96.7			25.7			0.0			129.6
Deferred tax assets		0.0		29.4			(13.2	)		2.2			0.0			18.4
Affiliated loan receivables		0.0		34.9			224.3			21.4			(280.6	)		0.0
Other assets		0.0		4.4			15.3			9.6			0.0			29.3
Total assets	$	99.9	$	1,103.9		$	808.5		$	487.3		$	(1,299.4	)	$	1,200.2
LIABILITIES AND EQUITY
Accounts payable	$	0.0	$	65.1		$	32.4		$	44.4		$	0.0		$	141.9
Affiliated payables		0.0		(90.3	)		13.8			2.2			74.3			0.0
Accrued liabilities		0.0		59.9			16.4			51.6			0.0			127.9
Current maturities of long-term debt		0.0		0.1			0.0			11.3			0.0			11.4
Total current liabilities		0.0		34.8			62.6			109.5			74.3			281.2
Long-term debt		0.0		643.3			0.0			22.3			0.0			665.6
Affiliated debt		0.0		233.7			19.3			27.6			(280.6	)		0.0
Other long-term liabilities		0.0		92.0			14.4			41.2			0.0			147.6
Total liabilities		0.0		1,003.8			96.3			200.6			(206.3	)		1,094.4
Koppers shareholders’ equity		99.9		100.1			712.2			280.8			(1,093.1	)		99.9
Noncontrolling interests		0.0		0.0			0.0			5.9			0.0			5.9
Total liabilities and equity	$	99.9	$	1,103.9		$	808.5		$	487.3		$	(1,299.4	)	$	1,200.2

Condensed Consolidating Statement of Cash Flows

For the Year Ended December 31, 2018

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Cash provided by (used in) operating activities	$	28.9		$	8.9		$	30.3		$	42.0		$	(31.8	)	$	78.3
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions		0.0			(338.0	)		(9.1	)		(26.6	)		0.0			(373.7	)
Repayments (loans to) from affiliates		0.0			13.9			(7.2	)		(14.6	)		7.9			0.0
Insurance proceeds received		0.0			0.0			0.0			1.5			0.0			1.5
Net cash proceeds (payments) from divestitures and asset sales		0.0			(8.5	)		0.0			4.3			0.0			(4.2	)
Net cash (used in) provided by investing activities		0.0			(332.6	)		(16.3	)		(35.4	)		7.9			(376.4	)
Cash provided by (used in) financing activities:
Borrowings (repayments) of long-term debt		0.0			327.4			(0.1	)		(12.7	)		0.0			314.6
Borrowings (repayments) of affiliated debt		0.0			32.4			(13.9	)		(10.6	)		(7.9	)		0.0
Deferred financing costs		0.0			(2.9	)		0.0			0.0			0.0			(2.9	)
Dividends paid		0.0			(31.8	)		(0.0	)		(0.0	)		31.8			0.0
Stock repurchased		(28.9	)		0.0			0.0			0.0			0.0			(28.9	)
Net cash provided by (used in) financing activities		(28.9	)		325.1			(14.0	)		(23.3	)		23.9			282.8
Effect of exchange rates on cash		0.0			0.0			0.0			(4.4	)		0.0			(4.4	)
Net increase (decrease) in cash and cash equivalents		0.0			1.4			0.0			(21.1	)		0.0			(19.7	)
Cash and cash equivalents at beginning of year		0.0			0.7			0.0			59.6			0.0			60.3
Cash and cash equivalents at end of period	$	0.0		$	2.1		$	0.0		$	38.5		$	0.0		$	40.6

Condensed Consolidating Statement of Cash Flows

For the Year Ended December 31, 2017

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Cash provided by (used in) operating activities	$	2.5		$	116.8		$	39.3		$	60.7		$	(117.5	)	$	101.8
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions		0.0			(42.2	)		(13.5	)		(11.8	)		0.0			(67.5	)
Repayments (loans to) from affiliates		0.0			(0.6	)		64.2			18.1			(81.7	)		0.0
Repayment of loan		0.0			0.0			0.0			9.5			0.0			9.5
Net proceeds (payments) from divestitures and asset sales		0.0			0.1			1.0			0.4			0.0			1.5
Net cash (used in) provided by investing activities		0.0			(42.7	)		51.7			16.2			(81.7	)		(56.5	)
Cash provided by (used in) financing activities:
Borrowings (repayments) of long-term debt		0.0			17.0			0.0			(9.3	)		(0.1	)		7.6
Borrowings (repayments) of affiliated debt		0.0			(75.6	)		9.1			(15.2	)		81.7			0.0
Deferred financing costs		0.0			(11.0	)		0.0			0.0			0.0			(11.0	)
Dividends paid		0.0			(3.8	)		(100.1	)		(13.7	)		117.6			0.0
Stock repurchased		(2.5	)		0.0			0.0			0.0			0.0			(2.5	)
Net cash used in financing activities		(2.5	)		(73.4	)		(91.0	)		(38.2	)		199.2			(5.9	)
Effect of exchange rates on cash		0.0			0.0			0.0			0.1			0.0			0.1
Net increase in cash and cash equivalents		0.0			0.7			0.0			38.8			0.0			39.5
Cash and cash equivalents at beginning of year		0.0			0.0			0.0			20.8			0.0			20.8
Cash and cash equivalents at end of period	$	0.0		$	0.7		$	0.0		$	59.6		$	0.0		$	60.3

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 (used in) provided by operating activities	$	(0.1	)	$	106.6		$	77.0		$	29.1		$	(93.1	)	$	119.5
Cash (used in) provided by 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 proceeds (payments) from divestitures and asset sales		0.0			0.0			0.9			(4.7	)		0.0			(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			0.0
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) provided by 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 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

Related Party Transactions and Equity Investments

12 Months Ended

Dec. 31, 2018

23. Related Party Transactions and Equity Investments

During 2016, the Company sold its 30 percent interest in TKK. The Company had loaned $10.0 million, gross of accumulated equity losses of $1.1 million, to TKK, including interest. The loan and interest was fully repaid and the Company recorded a gain of $1.3 million in 2017.

At December 31, 2017, KJCC had an outstanding loan from its 25-percent non-controlling shareholder of $2.5 million. This loan was repaid in November 2018.

Schedule II - Valuation and Qualifying Accounts

12 Months Ended

Dec. 31, 2018

Valuation And Qualifying Accounts [Abstract]

Schedule II - Valuation and Qualifying Accounts

SCHEDULE II – VALUATION AND QUALIFYING ACCOUNTS

For the years ended December 31, 2018, 2017 and 2016


	Balance at										Balance
	Beginning		Increase		Net			Currency			at End
	of Year		to Expense		Write-offs			Translation			of Year
(Dollars in millions)
2018
Allowance for doubtful accounts	$	2.5	$	0.7	$	(0.7	)	$	0.0		$	2.5
Deferred tax valuation allowance	$	44.5	$	15.8	$	0.0		$	(0.4	)	$	59.9
2017
Allowance for doubtful accounts	$	3.8	$	0.4	$	(1.8	)	$	0.1		$	2.5
Deferred tax valuation allowance	$	40.2	$	4.0	$	(0.5	)	$	0.8		$	44.5
2016
Allowance for doubtful accounts	$	6.5	$	0.7	$	(3.40	)	$	0.0		$	3.8
Deferred tax valuation allowance	$	41.9	$	0.9	$	(1.50	)	$	(1.1	)	$	40.2

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2018

Cash and Cash Equivalents

Basis of Presentation

Use of Estimates

Revenue Recognition

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

Asset Retirement Obligations

The following table describes changes to the Company’s asset retirement obligation liabilities:

	December 31,
	2018			2017
(Dollars in millions)
Asset retirement obligation at beginning of year	$	37.1		$	36.0
Accretion expense		1.7			2.4
Revision in estimated cash flows ^(a)		0.8			9.4
Cash expenditures		(12.5	)		(10.9	)
Currency translation		(0.1	)		0.2
Balance at end of period	$	27.0		$	37.1

Litigation and Contingencies

Environmental Liabilities

New Accounting Pronouncements

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Summary of Asset Retirement Obligation Liabilities

The following table describes changes to the Company’s asset retirement obligation liabilities:

	December 31,
	2018			2017
(Dollars in millions)
Asset retirement obligation at beginning of year	$	37.1		$	36.0
Accretion expense		1.7			2.4
Revision in estimated cash flows ^(a)		0.8			9.4
Cash expenditures		(12.5	)		(10.9	)
Currency translation		(0.1	)		0.2
Balance at end of period	$	27.0		$	37.1

Plant Closures and Discontinued Operations (Tables)

12 Months Ended

Dec. 31, 2018

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, 2016	$	1.4		$	1.5		$	10.0		$	3.2		$	16.1
Accrual		0.9			2.1			4.7			6.9			14.6
Costs charged against assets		0.0			0.0			0.0			(6.3	)		(6.3	)
Reversal of accrued charges		(0.3	)		0.0			(1.8	)		0.0			(2.1	)
Cash paid		(0.3	)		(1.1	)		(2.4	)		(1.0	)		(4.8	)
Currency translation		0.0			0.2			0.1			0.5			0.8
Reserve at December 31, 2017	$	1.7		$	2.7		$	10.6		$	3.3		$	18.3
Accrual		0.0			0.9			1.8			2.2			4.9
Costs charged against assets		0.0			0.0			0.0			(2.1	)		(2.1	)
Reversal of accrued charges		0.0			0.0			(0.9	)		0.0			(0.9	)
Cash paid		0.0			(3.4	)		(7.9	)		(0.5	)		(11.8	)
Currency translation		0.0			(0.2	)		0.0			(0.1	)		(0.3	)
Reserve at December 31, 2018	$	1.7		$	0.0		$	3.6		$	2.8		$	8.1

Acquisitions (Tables)

12 Months Ended

Dec. 31, 2018

Business Combinations [Abstract]

Summary of Valuation of Identifiable Assets Acquired and Liabilities Assumed Upon Acquisition

The valuation of identifiable assets acquired and liabilities assumed upon the acquisition of UIP and KRR are shown in the table below:

	UIP		KRR
(Dollars in millions)
Cash and cash equivalents	$	1.5	$	3.2
Accounts receivable		20.2		4.9
Inventory		43.1		0.0
Other current assets		1.2		0.3
Property, plant and equipment		19.6		6.6
Intangible assets, net		59.4		19.3
Goodwill		77.1		34.0
Other non-current assets		0.2		0.0
Total assets acquired		222.3		68.3
Accounts payable and accrued liabilities		18.7		2.3
Other non-current liabilities		0.8		0.0
Net assets acquired	$	202.8	$	66.0

Schedule of Identifiable Intangible Assets Acquired

Net assets acquired include identifiable intangible assets with respect to customer contracts, non-compete agreements and trademarks as summarized in the following tables:

			UIP
(Dollars in millions)	Amount		Remaining Life
Customer contracts	$	58.2	15 years
Non-compete agreements		1.2	5 years
Total UIP	$	59.4

			KRR
(Dollars in millions)	Amount		Remaining Life
Customer contracts	$	18.7	15 years
Trademarks		0.6	2 years
Total KRR	$	19.3

Summary of Revenue and Income from Continuing Operations

	Year Ended December 31,
	2018		2017
(Dollars in millions)
Pro forma revenue	$	1,760.9	$	1,622.5
Pro forma income from continuing operations attributable to Koppers		29.0		26.6
Pro forma income per share - continuing operations:
Basic -	$	1.39	$	1.28
Diluted -	$	1.36	$	1.21

Revenue Recognition (Tables)

12 Months Ended

Dec. 31, 2018

Revenue From Contract With Customer [Abstract]

Schedule of Revenue and Cost of Goods Sold Recognized Net Impact of Adopting Topic 606 Decrease in Sales and Cost of Sales

Revenue and cost of goods sold recognized during the year ended December 31, 2018 from the adoption of Topic 606 was $3.1 million and $2.9 million, respectively, and, as such, the net impact of adopting Topic 606 for the year ended December 31, 2018 was a decrease in sales and cost of sales as follows:

	Year Ended December 31,
	2018
(Dollars in millions)
Sales	$	(2.2	)
Cost of sales		(2.1	)

Earnings per Common Share (Tables)

12 Months Ended

Dec. 31, 2018

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,
	2018		2017			2016
(Dollars in millions, except share amounts, in thousands, and per share amounts)
Net income attributable to Koppers	$	23.4	$	29.1		$	29.3
Income (loss) from discontinued operations		0.4		(0.8	)		0.6
Income from continuing operations attributable to Koppers	$	23.0	$	29.9		$	28.7
Weighted average common shares outstanding:
Basic		20,871		20,754			20,636
Effect of dilutive securities		455		1,246			419
Diluted		21,326		22,000			21,055
Earnings per common share – continuing operations:
Basic earnings per common share	$	1.10	$	1.44		$	1.39
Diluted earnings per common share		1.08		1.36			1.36
Other data:
Antidilutive securities excluded from computation of diluted earnings per common share		401		156			415

Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2018

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

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:

	May 2018 Grant			March 2018 Grant			March 2017 Grant			March 2016 Grant			March 2015 Grant
Grant date price per share of stock option award	$	39.10		$	41.60		$	44.10		$	18.11		$	17.57
Expected dividend yield per share		0.00	%		0.00	%		0.00	%		0.00	%		3.40	%
Expected life in years		5.73			5.73			5.77			5.96			5.75
Expected volatility		37.05	%		37.05	%		39.70	%		40.86	%		42.27	%
Risk-free interest rate		2.82	%		2.67	%		2.13	%		1.45	%		1.73	%
Grant date fair value per share of option awards	$	15.48		$	16.38		$	17.90		$	7.41		$	5.20

Summary of Performance Stock Units

The following table shows a summary of the performance stock units as of December 31, 2018:

Performance Period

Minimum

Target

Maximum

2017 – 2019

110,262

220,524

2018 – 2020

128,093

256,186

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, 2018:

	Restricted Stock Units			Performance Stock Units			Total Stock Units			Weighted Average Grant Date Fair Value per Unit
Non-vested at January 1, 2018		238,140			581,551			819,691		$	29.14
Granted		121,947			134,351			256,298		$	43.53
Performance share adjustment		0			(16,402	)		(16,402	)	$	24.85
Vested		(118,972	)		(409,732	)		(528,704	)	$	20.19
Forfeited		(17,554	)		(18,645	)		(36,199	)	$	37.80
Non-vested at December 31, 2018		223,561			271,123			494,684		$	45.65

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, 2018:

	Options			Weighted Average Exercise Price per Option		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in millions)
Outstanding at December 31, 2017		942,537		$	27.59
Granted		144,825		$	41.50
Exercised		(79,055	)	$	26.37
Forfeited		(26,367	)	$	31.67
Outstanding at December 31, 2018		981,940		$	29.63		5.80	$	0.00
Exercisable at December 31, 2018		642,092		$	29.03		4.50	$	0.00

Schedule of Stock-based Compensation Expense Recognized

Stock Compensation Expense

Total stock-based compensation expense recognized under the Company’s LTIP and employee stock purchase plan for the three years ended December 31, 2018 are as follows:

	Year Ended December 31,
	2018		2017		2016
(Dollars in millions)
Stock-based compensation expense recognized:
Selling, general and administrative expenses	$	12.5	$	10.6	$	8.9
Less related income tax benefit		3.1		4.1		3.6
Decrease in net income attributable to Koppers	$	9.4	$	6.5	$	5.3
Intrinsic value of exercised stock options	$	1.1	$	1.3	$	0.1
Cash received from the exercise of stock options	$	2.9	$	2.7	$	0.4

Performance Stock Units [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

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:

	May 2018 Grant			March 2018 Grant			March 2017 Grant			March 2016 Grant
Grant date price per share of performance award	$	39.10		$	41.60		$	44.10		$	18.11
Expected dividend yield per share		0.00	%		0.00	%		0.00	%		0.00	%
Expected volatility		39.40	%		39.40	%		43.50	%		40.86	%
Risk-free interest rate		2.35	%		2.38	%		1.54	%		0.96	%
Look-back period in years		2.84			2.84			2.83			2.84
Grant date fair value per share of performance award	$	44.29		$	47.12		$	64.02		$	23.70

Segment Information (Tables)

12 Months Ended

Dec. 31, 2018

Segment Reporting [Abstract]

Summary of Results of Segment Operations

	Year Ended December 31,
	2018			2017			2016
(Dollars in millions)
Revenues from external customers:
Railroad and Utility Products and Services	$	634.8		$	512.6		$	586.5
Performance Chemicals		420.0			411.2			393.4
Carbon Materials and Chemicals		655.4			551.7			436.3
Total	$	1,710.2		$	1,475.5		$	1,416.2
Intersegment revenues:
Performance Chemicals	$	10.8		$	6.7		$	8.1
Carbon Materials and Chemicals		77.3			79.6			90.2
Total	$	88.1		$	86.3		$	98.3
Depreciation and amortization expense:
Railroad and Utility Products and Services	$	17.7		$	11.8		$	11.9
Performance Chemicals		17.8			17.9			18.7
Carbon Materials and Chemicals^(a)		15.3			20.1			22.3
Total	$	50.8		$	49.8		$	52.9
Operating profit (loss):
Railroad and Utility Products and Services^(b)	$	5.9		$	26.2		$	54.1
Performance Chemicals		36.2			71.4			63.5
Carbon Materials and Chemicals^(c)		70.7			28.0			(22.6	)
Corporate^(d)		(2.4	)		(2.0	)		(1.6	)
Total	$	110.4		$	123.6		$	93.4
Capital expenditures (excluding acquisitions):
Railroad and Utility Products and Services	$	19.2		$	10.6		$	11.2
Performance Chemicals		15.1			15.4			7.9
Carbon Materials and Chemicals		73.5			39.7			29.5
Corporate		1.9			1.8			1.3
Total	$	109.7		$	67.5		$	49.9

(a)	Excludes impairment charges of $3.7 million and $3.5 million in 2017 and 2016, respectively, for CMC.

(b)

(c)	Includes plant closure costs of $3.9 million, $14.6 million and $13.2 million in 2018, 2017 and 2016, respectively, for CMC.

(d)	Operating loss for Corporate includes costs for Koppers Holdings Inc., the parent company of Koppers Inc., and acquisition-related costs.

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,
	2018		2017
(Dollars in millions)
Segment assets:
Railroad and Utility Products and Services	$	538.0	$	249.7
Performance Chemicals		446.9		494.0
Carbon Materials and Chemicals		457.1		414.2
Segment assets		1,442.0		1,157.9
Cash and cash equivalents		2.1		0.7
Income tax receivable		2.8		1.7
Deferred taxes		20.5		29.4
Property, plant and equipment, net		6.0		5.2
Prepaid insurance and other assets		6.5		5.3
Total	$	1,479.9	$	1,200.2
Goodwill:
Railroad and Utility Products and Services	$	121.1	$	10.5
Performance Chemicals		175.4		177.7
Total	$	296.5	$	188.2

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		2018	$	993.5	$	732.1
		2017		852.2		479.5
		2016		929.3		446.6
Australasia		2018		365.4		128.8
		2017		312.8		131.4
		2016		228.4		124.3
Europe		2018		214.6		44.8
		2017		173.1		44.8
		2016		140.2		31.9
Other countries		2018		136.7		18.3
		2017		137.4		19.4
		2016		118.3		19.5
Total		2018	$	1,710.2	$	924.1
		2017	$	1,475.5	$	675.1
		2016	$	1,416.2	$	622.3

Schedule of Segment Revenues for Significant Product Lines

Segment Revenues for Significant Product Lines

	Year Ended December 31,
	2018		2017		2016
(Dollars in millions)
Railroad and Utility Products and Services:
Railroad treated products	$	341.7	$	380.4	$	435.9
Utility poles		184.7		46.0		42.1
Rail joints		33.5		28.2		24.4
Railroad infrastructure services		36.9		34.8		43.4
Other products		38.0		23.2		40.7
		634.8		512.6		586.5
Performance Chemicals:
Wood preservative products		371.4		383.8		365.5
Other products		48.7		27.4		27.9
		420.0		411.2		393.4
Carbon Materials and Chemicals:
Pitch and related products		403.1		275.8		232.9
Creosote and distillates		84.1		83.7		73.2
Phthalic anhydride and other chemicals		84.6		89.8		73.3
Naphthalene		40.8		38.9		32.1
Other products		42.8		63.5		24.8
		655.4		551.7		436.3
Total	$	1,710.2	$	1,475.5	$	1,416.2

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

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,
	2018			2017			2016
(Dollars in millions)
Current:
Federal	$	(1.2	)	$	11.1		$	(1.9	)
State		0.1			0.6			1.3
Foreign		18.0			15.7			13.3
Total current tax provision		16.9			27.4			12.7
Deferred:
Federal		9.6			2.6			(1.6	)
State		(0.2	)		(1.2	)		0.5
Foreign		(0.3	)		0.2			(0.2	)
Total deferred tax provision (benefit)		9.1			1.6			(1.3	)
Total income tax provision	$	26.0		$	29.0		$	11.4

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,
	2018			2017			2016
Federal income tax rate		21.0	%		35.0	%		35.0	%
State income taxes, net of federal tax benefit		(3.4	)		(1.6	)		(0.8	)
Foreign earnings taxed at different rates		1.7			(21.6	)		(10.1	)
Valuation allowance adjustments		6.2			0.9			(1.9	)
Transition tax from Tax Act		15.5			21.7			0.0
GILTI inclusion, net of foreign tax credits		12.0			0.0			0.0
Deferred tax adjustments		2.3			0.0			(0.2	)
Change in tax contingency reserves		(2.0	)		2.2			6.5
Deferred tax adjustments from Tax Act		(6.8	)		12.3			0.0
Other		0.9			(0.8	)		1.1
		47.4	%		48.1	%		29.6	%

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,
	2018			2017
(Dollars in millions)
Deferred tax assets:
Tax credits	$	27.0		$	15.0
Reserves, including insurance, environmental and deferred revenue		20.2			14.3
Federal and state tax loss carryforwards, expiring from 2019 to 2038		18.5			21.2
Pension and other postretirement benefits obligations		11.1			10.8
Asset retirement obligations		8.8			11.9
Foreign tax loss carryforwards, expiring beginning in 2019		5.5			9.3
Accrued employee compensation		5.4			6.3
Loss on derivative contracts		2.1			0.0
Book/tax inventory accounting differences		1.9			1.5
Other		4.9			6.1
Valuation allowance		(59.9	)		(44.5	)
Total deferred tax assets		45.5			51.9
Deferred tax liabilities:
Tax over book depreciation and amortization		35.7			33.2
Gain on derivative contracts		0.0			7.0
Other		1.1			0.7
Total deferred tax liabilities		36.8			40.9
Net deferred tax assets	$	8.7		$	11.0

Summary of Valuation Allowances Recorded to Offset Deferred Tax Assets

	December 31,
	2018		2017
Federal foreign tax credits	$	25.7	$	13.8
State temporary differences, net operating losses and tax credits		21.1		18.7
Federal temporary differences		7.0		0.0
Foreign temporary differences, net operating losses and capital losses		6.1		12.0
Total valuation allowances	$	59.9	$	44.5

Summary of Unrecognized Tax Benefits

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

	December 31,
	2018			2017			2016
(Dollars in millions)
Balance at beginning of year	$	8.7		$	9.7		$	7.7
Additions based on tax provisions related to the current year		0.1			0.1			0.9
Additions for tax provisions of prior years		0.0			2.7			1.5
Reductions of tax provisions of prior years		(1.5	)		(3.4	)		0.0
Reductions resulting from a lapse in the statute of limitations		(0.3	)		(0.4	)		(0.4	)
Balance at end of year	$	7.0		$	8.7		$	9.7

Inventories (Tables)

12 Months Ended

Dec. 31, 2018

Inventory Disclosure [Abstract]

Components of Inventories

Inventories as of December 31, 2018 and 2017 were as follows:

	December 31,
	2018		2017
(Dollars in millions)
Raw materials	$	199.5	$	173.6
Work in process		16.0		11.2
Finished goods		128.1		98.4
		343.6		283.2
Less revaluation to LIFO		58.9		46.3
Net	$	284.7	$	236.9

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2018

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, 2018 and 2017 are as follows:

	December 31, 2018				December 31, 2017
	Fair Value		Carrying Value		Fair Value		Carrying Value
(Dollars in millions)
Financial assets:
Cash and cash equivalents, including restricted cash	$	40.6	$	40.6	$	60.3	$	60.3
Investments and other assets		1.2		1.2		1.1		1.1
Financial liabilities:
Long-term debt (including current portion)	$	945.3	$	1,002.6	$	706.9	$	688.7

Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2018

Property Plant And Equipment [Abstract]

Property, Plant and Equipment

Property, plant and equipment as of December 31, 2018 and 2017 were as follows:

	December 31,
	2018		2017
(Dollars in millions)
Land	$	17.5	$	17.6
Buildings		65.1		63.4
Machinery and equipment		800.9		756.6
		883.5	$	837.6
Less accumulated depreciation		465.6		509.6
Net	$	417.9	$	328.0

Goodwill and Other Identifiable Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2018

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, 2018 and December 31, 2017 was as follows:

	Railroad and Utility Products and Services			Performance Chemicals			Total
(Dollars in millions)
Balance at December 31, 2016	$	9.9		$	176.5		$	186.4
Currency translation		0.6			1.2			1.8
Balance at December 31, 2017	$	10.5		$	177.7		$	188.2
Acquisitions		111.1			0.0			111.1
Currency translation		(0.5	)		(2.3	)		(2.8	)
Balance at December 31, 2018	$	121.1		$	175.4		$	296.5

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,
					2018						2017
	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			12.3	$	228.8	$	56.5	$	172.3	$	154.7	$	43.9	$	110.8
Technology	4 to 12			4.0		26.7		16.2		10.5		26.8		12.5		14.3
Trademarks	2 to 17			4.0		7.6		3.5		4.1		6.5		2.7		3.8
Supply contracts		10		2.2		2.4		2.1		0.3		2.5		2.0		0.5
Non-compete agreements		12		6.8		1.6		0.8		0.8		1.4		1.2		0.2
Favorable lease agreements		3		0.0		0.7		0.7		0.0		0.7		0.7		0.0
Total				11.1	$	267.8	$	79.8	$	188.0	$	192.6	$	63.0	$	129.6

Schedule of Future Amortization Expense

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

	Estimated annual amortization
(Dollars in millions)
2019	$	20.3
2020		19.3
2021		17.3
2022		14.5
2023		13.0

Pensions and Post-Retirement Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2018

Compensation And Retirement Disclosure [Abstract]

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

Net periodic pension costs for 2018, 2017 and 2016 were as follows:

	Year Ended December 31,
	Pension Benefits									Other Benefits
	2018			2017			2016			2018		2017			2016
(Dollars in millions)
Service cost	$	1.9		$	2.0		$	1.7		$	0.1	$	0.1		$	0.1
Interest cost		7.5			9.0			11.0			0.4		0.4			0.4
Expected return on plan assets		(8.5	)		(9.6	)		(10.5	)		0.0		0.0			0.0
Amortization of net loss (gain)		1.4			1.9			2.2			0.0		(0.2	)		(0.4	)
Settlements and curtailments		0.0			10.0			4.4			0.0		0.0			0.0
Net periodic benefit cost	$	2.3		$	13.3		$	8.8		$	0.5	$	0.3		$	0.1

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, 2018 and December 31, 2017 is as follows:

	Year Ended December 31,
	Pension Benefits						Other Benefits
	2018			2017			2018			2017
(Dollars in millions)
Change in benefit obligation:
Benefit obligation at beginning of year	$	219.1		$	243.6		$	11.1		$	10.0
Service cost		1.9			2.0			0.1			0.1
Interest cost		7.5			9.0			0.4			0.4
Actuarial (gains) losses		(13.2	)		7.3			(1.7	)		1.5
Plan amendments		0.7			0.0			0.0			0.0
Settlements		0.0			(36.9	)		0.0			0.0
Currency translation		(3.5	)		5.5			0.0			0.0
Benefits paid		(10.8	)		(11.4	)		(0.5	)		(0.9	)
Benefit obligation at end of year		201.7			219.1			9.4			11.1
Change in plan assets:
Fair value of plan assets at beginning of year		188.8			200.9			0.0			0.0
Actual return on plan assets		(8.6	)		19.5			0.0			0.0
Employer contribution		4.2			11.2			0.5			0.9
Settlements		0.0			(36.9	)		0.0			0.0
Currency translation		(4.0	)		5.5			0.0			0.0
Benefits paid		(10.8	)		(11.4	)		(0.5	)		(0.9	)
Fair value of plan assets at end of year		169.6			188.8			0.0			0.0
Funded status of the plan	$	(32.1	)	$	(30.3	)	$	(9.4	)	$	(11.1	)

Plan Data

	Year Ended December 31,
	Pension Benefits				Other Benefits
	2018		2017		2018		2017
(Dollars in millions)
Amounts recognized in the balance sheet consist of:
Noncurrent assets	$	8.9	$	7.0	$	0.0	$	0.0
Current liabilities		1.2		1.1		1.0		1.0
Noncurrent liabilities		39.8		36.2		8.4		10.1
Pension plans with projected benefit obligations in excess of plan assets:
Benefit obligation	$	148.6	$	159.9
Fair value of plan assets		107.7		122.6
Pension plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligation	$	148.4	$	159.6
Fair value of plan assets		107.7		122.6

Schedule of Projected Benefit Payments

	Pension Benefits		Other Benefits
(Dollars in millions)
2019	$	11.2	$	0.9
2020		11.1		0.9
2021		11.3		0.7
2022		11.5		0.7
2023		11.6		0.6
Next five years		64.0		2.9

Schedule of Weighted-Average Assumptions

Weighted-Average Assumptions as of December 31

	December 31,
	Pension Benefits						Other Benefits
	2018			2017			2018			2017
Discount rate		4.03	%		3.51	%		4.45	%		3.88	%
Expected return on plan assets		4.83			4.62
Rate of compensation increase		3.41			3.50
Initial medical trend rate								5.90			6.10

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,
	2018			2017
Debt securities		72	%		64	%
Equity securities		24			30
Other		4			6
		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, 2018 and December 31, 2017:

	As of December 31, 2018
	Quoted prices in active markets for identical assets (Level 1)		Significant observable inputs (Level 2)		Significant unobservable inputs (Level 3)		Total
(Dollars in millions)
U.S. equity securities	$	12.3	$	9.7	$	0.0	$	22.0
International equity securities		14.2		5.2		0.0		19.4
U.S. debt securities		34.3		39.0		0.0		73.3
International debt securities		5.3		43.1		0.0		48.4
Real estate and other investments		0.0		1.3		3.2		4.5
Cash and cash equivalents		0.0		2.0		0.0		2.0
	$	66.1	$	100.3	$	3.2	$	169.6

	As of December 31, 2017
	Quoted prices in active markets for identical assets (Level 1)		Significant observable inputs (Level 2)		Significant unobservable inputs (Level 3)		Total
(Dollars in millions)
U.S. equity securities	$	18.6	$	12.7	$	0.0	$	31.3
International equity securities		15.0		10.2		0.0	25.2
U.S. debt securities	21.4			53.0		2.5	76.9
International debt securities		7.5	34.8			1.0	43.3
Real estate and other investments	0.5		0.8			8.3	9.6
Cash and cash equivalents		0.0	2.5			0.0	2.5
	$	63.0	$	114.0	$	11.8	$	188.8

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, 2018:

	As of December 31, 2018
	Other Investments			Debt Securities
(Dollars in millions)
Balance at beginning of year	$	8.3		$	3.5
Purchases, sales, issuances and settlements		(4.3	)		(3.4	)
Realized and unrealized gains		(0.8	)		(0.1	)
Balance at the end of year	$	3.2		$	0.0
The amount of total losses during the period attributable to the change in unrealized losses relating to Level 3 net assets still held at the reporting date	$	(0.1	)	$	0.0

Debt (Tables)

12 Months Ended

Dec. 31, 2018

Schedule of Long-Term Debt Instruments

Debt as of December 31, 2018 and 2017 was as follows:

					December 31,
	Weighted Average Interest Rate			Maturity	2018		2017
Term Loan		5.65	%	2023	$	92.5	$	0.0
Revolving Credit Facility		5.65	%	2023		390.0		155.0
Construction and other loans		4.59	%	2020		20.1		33.7
Senior Notes due 2025		6.00	%	2025		500.0		500.0
Total debt						1,002.6		688.7
Less short-term debt and current maturities of long-term debt						11.6		11.4
Less unamortized debt issuance costs						12.2		11.7
Long-term debt					$	978.8	$	665.6

Schedule of Debt Maturities

At December 31, 2018 the aggregate debt maturities for the next five years are as follows:


(Dollars in millions)
2019	$	11.6
2020		28.4
2021		10.0
2022		452.6
2023		0.0
Thereafter		500.0
Total debt	$	1,002.6

- 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://fasb.org/us-gaap/role/ref/legacyRef
-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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28541-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21521-112644

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21538-112644

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

+ Details

Leases (Tables)

12 Months Ended

Dec. 31, 2018

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)
2019	$	30.3
2020		23.7
2021		18.3
2022		14.9
2023		10.9
Thereafter		36.0
Total	$	134.1

Derivative Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2018

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Schedule of Outstanding Copper Swap Contracts

As of December 31, 2018 and December 31, 2017, the Company had outstanding copper swap contracts of the following amounts:

	Units Outstanding (in Pounds)			Net Fair Value - Asset (Liability)
	December 31,			December 31,
	2018		2017	2018			2017
(Amounts in millions)
Cash flow hedges		35.5	37.8	$	(6.8	)	$	25.5
Not designated as hedges		13.3	11.3		(2.4	)		4.5
Total		48.8	49.1	$	(9.2	)	$	30.0

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

As of December 31, 2018 and December 31, 2017, the fair value of the outstanding copper swap contracts is recorded in the balance sheet as follows:

	December 31,
	2018			2017
(Dollars in millions)
Other current assets	$	0.0		$	21.8
Other assets		0.0			8.2
Accrued liabilities		(9.0	)		0.0
Other long-term liabilities		(0.2	)		0.0
Net (liability) asset on balance sheet	$	(9.2	)	$	30.0
Accumulated other comprehensive (loss) gain, net of tax	$	(5.3	)	$	15.8

Summary of Amount Recognized in Earnings Related to Copper Swap Contracts

	Year Ended December 31,
	2018			2017
(Dollars in millions)
Gain from ineffectiveness of cash flow hedges	$	0.0		$	5.6
(Loss) gain from contracts not designated as hedges		(6.9	)		3.5
Net	$	(6.9	)	$	9.1

Schedule of Fair Value of Outstanding Foreign Currency Forward Contracts

As of December 31, 2018 and December 31, 2017, the fair value of outstanding foreign currency forward contracts is recorded in the balance sheet as follows:

	December 31,
	2018			2017
(Dollars in millions)
Other current assets	$	0.9		$	0.3
Accrued liabilities		(1.0	)		(0.2	)
Net (liability) asset on balance sheet	$	(0.1	)	$	0.1

Summary of Net Currency Units Outstanding

As of December 31, 2018 and 2017, the net currency units outstanding were:

	December 31,
	2018		2017
(In millions)
British Pounds		GBP 5.7		GBP 7.0
New Zealand Dollars		NZD 16.0		NZD 15.5
United States Dollars		USD 6.0		USD 12.5
Canadian Dollars		CAD 0.0		CAD 2.5
Euro		EUR 1.2		EUR 0.0

Common Stock and Senior Convertible Preferred Stock (Tables)

12 Months Ended

Dec. 31, 2018

Equity [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, 2018 are as follows:

	December 31,
	2018			2017			2016
(Shares in thousands)
Senior Convertible Preferred Stock:
Balance at beginning and end of year		0			0			0
Common Stock:
Balance at beginning of year		22,384			22,141			22,016
Issued for employee stock plans		645			243			125
Balance at end of year		23,029			22,384			22,141
Treasury Stock:
Balance at beginning of year		(1,606	)		(1,476	)		(1,459	)
Shares repurchased		(874	)		(130	)		(17	)
Balance at end of year		(2,480	)		(1,606	)		(1,476	)

- 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

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+ Details

Commitments and Contingent Liabilities (Tables)

12 Months Ended

Dec. 31, 2018

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 $3.5 million and $5.1 million are classified as current liabilities at December 31, 2018 and 2017

	December 31,
	2018			2017
(Dollars in millions)
Balance at beginning of year	$	13.9		$	12.9
Expense		0.9			3.2
Revision of reserves		(2.4	)		(0.7	)
Cash expenditures		(3.8	)		(1.8	)
Acquisition		1.9			0.0
Currency translation		(0.4	)		0.3
Balance at end of period	$	10.1		$	13.9

Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2018

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, 2018 and 2017:

	Year Ended December 31, 2018
	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	$	406.1	$	436.0	$	442.7	$	425.4		$	1,710.2
Operating profit		43.3		22.3		31.2		13.6			110.4
Income (loss) from continuing operations ^(a)		23.8		0.5		6.9		(2.4	)		28.8
Net income (loss) ^(a)		23.7		1.0		6.9		(2.4	)		29.2
Net income (loss) attributable to Koppers^(a)		17.8		0.6		7.6		(2.6	)		23.4
Common stock data:
Earnings (loss) per common share attributable to Koppers common shareholders: ^(a)(b)
Basic –
Continuing operations	$	0.86	$	0.01	$	0.36	$	(0.13	)	$	1.10
Discontinued operations		0.00		0.02		0.00		0.00			0.02
Earnings (loss) per basic common share	$	0.86	$	0.03	$	0.36	$	(0.13	)	$	1.12
Diluted –
Continuing operations	$	0.81	$	0.01	$	0.35	$	(0.13	)	$	1.08
Discontinued operations		0.00		0.02		0.00		0.00			0.02
Earnings (loss) per diluted common share	$	0.81	$	0.03	$	0.35	$	(0.13	)	$	1.10

	Year Ended December 31, 2017
	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	$	346.6	$	378.0		$	384.8	$	366.1		$	1,475.50
Operating profit ^(c)		28.1		38.1			43.8		13.6			123.6
Income (loss) from continuing operations		4.7		20.9			20.0		(14.3	)		31.3
Net income (loss)		4.6		19.8			19.9		(13.8	)		30.5
Net income (loss) attributable to Koppers		4.4		19.7			19.8		(14.8	)		29.1
Common stock data:
Earnings (loss) per common share attributable to Koppers common shareholders: ^(b)
Basic –
Continuing operations	$	0.21	$	1.00		$	0.96	$	(0.73	)	$	1.44
Discontinued operations		0.00		(0.06	)		0.00		0.02			(0.04	)
Earnings (loss) per basic common share	$	0.21	$	0.94		$	0.96	$	(0.71	)	$	1.40
Diluted –
Continuing operations	$	0.20	$	0.95		$	0.91	$	(0.73	)	$	1.36
Discontinued operations		0.00		(0.05	)		0.00		0.02			(0.04	)
Earnings (loss) per diluted common share	$	0.20	$	0.90		$	0.91	$	(0.71	)	$	1.32

(a) Income tax expense for the fourth quarter of 2017 was increased by $20.5 million due to the impact of the Tax Cuts and Jobs Act which was signed into law on December 22, 2017.

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

12 Months Ended

Dec. 31, 2018

Condensed Consolidating Statement of Comprehensive (Loss) Income

For the Year Ended December 31, 2018

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries		Consolidating Adjustments			Consolidated
(Dollars in millions)
Net sales	$	0.0		$	569.6		$	350.2		$	874.4	$	(84.0	)	$	1,710.2
Cost of sales including depreciation, amortization and restructuring		0.0			530.8			272.0			711.3		(84.2	)		1,429.9
Gain on sale of assets		0.0			6.2			0.0			2.1		0.0			8.3
Selling, general and administrative		2.4			52.2			46.4			60.6		0.0			161.6
Operating profit (loss)		(2.4	)		(19.6	)		31.8			100.4		0.2			110.4
Other income (loss)		0.0			(4.0	)		1.5			3.2		0.0			0.7
Equity income of subsidiaries		25.3			88.4			82.4			0.0		(196.1	)		0.0
Interest expense (income)		0.0			53.9			(0.1	)		2.5		0.0			56.3
Income taxes		(0.5	)		(14.4	)		24.0			16.9		0.0			26.0
Income (loss) from continuing operations		23.4			25.3			91.8			84.2		(195.9	)		28.8
Discontinued operations		0.0			0.0			0.0			0.4		0.0			0.4
Noncontrolling interests		0.0			0.0			0.0			5.8		0.0			5.8
Net income (loss) attributable to Koppers	$	23.4		$	25.3		$	91.8		$	78.8	$	(195.9	)	$	23.4
Comprehensive (loss) income attributable to Koppers	$	(27.4	)	$	(25.4	)	$	41.0		$	52.9	$	(68.5	)	$	(27.4	)

Condensed Consolidating Statement of Comprehensive (Loss) Income

For the Year Ended December 31, 2017

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries		Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Net sales	$	0.0		$	590.6		$	344.9	$	623.3		$	(83.3	)	$	1,475.5
Cost of sales including depreciation and amortization		0.0			570.2			235.0		496.3			(82.1	)		1,219.4
Selling, general and administrative		1.9			46.9			43.3		40.4			0.0			132.5
Operating profit (loss)		(1.9	)		(26.5	)		66.6		86.6			(1.2	)		123.6
Other income (loss)		0.0			(1.0	)		2.4		2.3			(1.2	)		2.5
Equity income of subsidiaries		30.3			103.8			64.7		0.0			(198.8	)		0.0
Interest expense		0.0			39.0			0.0		4.7			(1.2	)		42.5
Loss on pension settlement		0.0			10.0			0.0		0.0			0.0			10.0
Loss on extinguishment of debt		0.0			13.3			0.0		0.0			0.0			13.3
Income taxes		(0.7	)		(16.4	)		30.0		16.2			(0.1	)		29.0
Income (loss) from continuing operations		29.1			30.4			103.7		68.0			(199.9	)		31.3
Discontinued operations		0.0			0.0			0.0		(0.8	)		0.0			(0.8	)
Noncontrolling interests		0.0			0.0			0.0		1.4			0.0			1.4
Net income (loss) attributable to Koppers	$	29.1		$	30.4		$	103.7	$	65.8		$	(199.9	)	$	29.1
Comprehensive income (loss) attributable to Koppers	$	60.7		$	61.8		$	132.8	$	89.2		$	(283.8	)	$	60.7

Condensed Consolidating Statement of Comprehensive (Loss) Income

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			635.7			252.3		412.4			(101.2	)		1,199.2
Gain on sale of assets		0.0			0.0			0.0		(2.1	)		0.0			(2.1	)
Selling, general and administrative		1.9			42.4			38.2		43.2			0.0			125.7
Operating profit (loss)		(1.9	)		(17.4	)		60.1		51.2			1.4			93.4
Other income (loss)		0.0			(2.3	)		4.1		0.3			(1.8	)		0.3
Equity income of subsidiaries		30.6			79.1			35.9		0.0			(145.6	)		0.0
Interest expense		0.0			47.6			0.0		5.0			(1.8	)		50.8
Loss on pension settlement		0.0			4.4			0.0		0.0			0.0			4.4
Income taxes		(0.6	)		(23.2	)		22.2		13.0			0.0			11.4
Income (loss) 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 (loss) 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 Balance Sheet

December 31, 2018

	Parent		Koppers Inc.		Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries		Consolidating Adjustments			Consolidated
(Dollars in millions)
ASSETS
Cash and cash equivalents	$	0.0	$	2.1	$	0.0		$	38.5	$	0.0		$	40.6
Receivables, net		0.0		57.8		28.5			106.2		0.0			192.5
Affiliated receivables		0.5		69.2		16.6			3.1		(89.4	)		0.0
Inventories, net		0.0		105.6		30.2			150.8		(1.9	)		284.7
Other current assets		0.0		3.8		2.2			16.3		0.2			22.5
Total current assets		0.5		238.5		77.5			314.9		(91.1	)		540.3
Equity investments		55.7		984.4		333.1			0.0		(1,373.2	)		0.0
Property, plant and equipment, net		0.0		212.0		51.4			154.5		0.0			417.9
Goodwill		0.0		0.8		153.1			142.6		0.0			296.5
Intangible assets, net		0.0		6.5		86.5			95.0		0.0			188.0
Deferred tax assets		0.0		20.5		(7.3	)		2.3		0.0			15.5
Affiliated loan receivables		0.0		27.2		148.3			18.4		(193.9	)		0.0
Other assets		0.0		4.8		4.7			12.2		0.0			21.7
Total assets	$	56.2	$	1,494.7	$	847.3		$	739.9	$	(1,658.2	)	$	1,479.9
LIABILITIES AND EQUITY
Accounts payable	$	0.0	$	76.9	$	43.0		$	57.3	$	0.0		$	177.2
Affiliated payables		0.0		81.4		0.4			7.6		(89.4	)		0.0
Accrued liabilities		0.0		53.9		22.4			33.6		0.0			109.9
Current maturities of long-term debt		0.0		10.0		0.1			1.5		0.0			11.6
Total current liabilities		0.0		222.2		65.9			100.0		(89.4	)		298.7
Long-term debt		0.0		960.3		0.1			18.4		0.0			978.8
Affiliated debt		0.0		166.7		18.7			8.5		(193.9	)		0.0
Other long-term liabilities		0.0		88.9		8.6			37.9		0.0			135.4
Total liabilities		0.0		1,438.1		93.3			164.8		(283.3	)		1,412.9
Koppers shareholders’ equity		56.2		56.6		754.0			564.3		(1,374.9	)		56.2
Noncontrolling interests		0.0		0.0		0.0			10.8		0.0			10.8
Total liabilities and equity	$	56.2	$	1,494.7	$	847.3		$	739.9	$	(1,658.2	)	$	1,479.9

Condensed Consolidating Balance Sheet

December 31, 2017

	Parent		Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
ASSETS
Cash and cash equivalents	$	0.0	$	0.7		$	0.0		$	59.6		$	0.0		$	60.3
Receivables, net		0.0		48.6			27.7			84.6			0.0			160.9
Affiliated receivables		0.6		19.4			(83.0	)		(12.1	)		75.1			0.0
Inventories, net		0.0		80.4			40.5			117.9			(1.9	)		236.9
Deferred tax assets		0.0		0.0			0.0			(0.1	)		0.1			0.0
Other current assets		0.0		6.6			23.0			18.8			0.2			48.6
Total current assets		0.6		155.7			8.2			268.7			73.5			506.7
Equity investments		99.3		716.3			276.8			(0.1	)		(1,092.3	)		0.0
Property, plant and equipment, net		0.0		155.2			47.3			125.5			0.0			328.0
Goodwill		0.0		0.8			153.1			34.3			0.0			188.2
Intangible assets, net		0.0		7.2			96.7			25.7			0.0			129.6
Deferred tax assets		0.0		29.4			(13.2	)		2.2			0.0			18.4
Affiliated loan receivables		0.0		34.9			224.3			21.4			(280.6	)		0.0
Other assets		0.0		4.4			15.3			9.6			0.0			29.3
Total assets	$	99.9	$	1,103.9		$	808.5		$	487.3		$	(1,299.4	)	$	1,200.2
LIABILITIES AND EQUITY
Accounts payable	$	0.0	$	65.1		$	32.4		$	44.4		$	0.0		$	141.9
Affiliated payables		0.0		(90.3	)		13.8			2.2			74.3			0.0
Accrued liabilities		0.0		59.9			16.4			51.6			0.0			127.9
Current maturities of long-term debt		0.0		0.1			0.0			11.3			0.0			11.4
Total current liabilities		0.0		34.8			62.6			109.5			74.3			281.2
Long-term debt		0.0		643.3			0.0			22.3			0.0			665.6
Affiliated debt		0.0		233.7			19.3			27.6			(280.6	)		0.0
Other long-term liabilities		0.0		92.0			14.4			41.2			0.0			147.6
Total liabilities		0.0		1,003.8			96.3			200.6			(206.3	)		1,094.4
Koppers shareholders’ equity		99.9		100.1			712.2			280.8			(1,093.1	)		99.9
Noncontrolling interests		0.0		0.0			0.0			5.9			0.0			5.9
Total liabilities and equity	$	99.9	$	1,103.9		$	808.5		$	487.3		$	(1,299.4	)	$	1,200.2

Condensed Consolidating Statement of Cash Flows

For the Year Ended December 31, 2018

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Cash provided by (used in) operating activities	$	28.9		$	8.9		$	30.3		$	42.0		$	(31.8	)	$	78.3
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions		0.0			(338.0	)		(9.1	)		(26.6	)		0.0			(373.7	)
Repayments (loans to) from affiliates		0.0			13.9			(7.2	)		(14.6	)		7.9			0.0
Insurance proceeds received		0.0			0.0			0.0			1.5			0.0			1.5
Net cash proceeds (payments) from divestitures and asset sales		0.0			(8.5	)		0.0			4.3			0.0			(4.2	)
Net cash (used in) provided by investing activities		0.0			(332.6	)		(16.3	)		(35.4	)		7.9			(376.4	)
Cash provided by (used in) financing activities:
Borrowings (repayments) of long-term debt		0.0			327.4			(0.1	)		(12.7	)		0.0			314.6
Borrowings (repayments) of affiliated debt		0.0			32.4			(13.9	)		(10.6	)		(7.9	)		0.0
Deferred financing costs		0.0			(2.9	)		0.0			0.0			0.0			(2.9	)
Dividends paid		0.0			(31.8	)		(0.0	)		(0.0	)		31.8			0.0
Stock repurchased		(28.9	)		0.0			0.0			0.0			0.0			(28.9	)
Net cash provided by (used in) financing activities		(28.9	)		325.1			(14.0	)		(23.3	)		23.9			282.8
Effect of exchange rates on cash		0.0			0.0			0.0			(4.4	)		0.0			(4.4	)
Net increase (decrease) in cash and cash equivalents		0.0			1.4			0.0			(21.1	)		0.0			(19.7	)
Cash and cash equivalents at beginning of year		0.0			0.7			0.0			59.6			0.0			60.3
Cash and cash equivalents at end of period	$	0.0		$	2.1		$	0.0		$	38.5		$	0.0		$	40.6

Condensed Consolidating Statement of Cash Flows

For the Year Ended December 31, 2017

	Parent			Koppers Inc.			Domestic Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
(Dollars in millions)
Cash provided by (used in) operating activities	$	2.5		$	116.8		$	39.3		$	60.7		$	(117.5	)	$	101.8
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions		0.0			(42.2	)		(13.5	)		(11.8	)		0.0			(67.5	)
Repayments (loans to) from affiliates		0.0			(0.6	)		64.2			18.1			(81.7	)		0.0
Repayment of loan		0.0			0.0			0.0			9.5			0.0			9.5
Net proceeds (payments) from divestitures and asset sales		0.0			0.1			1.0			0.4			0.0			1.5
Net cash (used in) provided by investing activities		0.0			(42.7	)		51.7			16.2			(81.7	)		(56.5	)
Cash provided by (used in) financing activities:
Borrowings (repayments) of long-term debt		0.0			17.0			0.0			(9.3	)		(0.1	)		7.6
Borrowings (repayments) of affiliated debt		0.0			(75.6	)		9.1			(15.2	)		81.7			0.0
Deferred financing costs		0.0			(11.0	)		0.0			0.0			0.0			(11.0	)
Dividends paid		0.0			(3.8	)		(100.1	)		(13.7	)		117.6			0.0
Stock repurchased		(2.5	)		0.0			0.0			0.0			0.0			(2.5	)
Net cash used in financing activities		(2.5	)		(73.4	)		(91.0	)		(38.2	)		199.2			(5.9	)
Effect of exchange rates on cash		0.0			0.0			0.0			0.1			0.0			0.1
Net increase in cash and cash equivalents		0.0			0.7			0.0			38.8			0.0			39.5
Cash and cash equivalents at beginning of year		0.0			0.0			0.0			20.8			0.0			20.8
Cash and cash equivalents at end of period	$	0.0		$	0.7		$	0.0		$	59.6		$	0.0		$	60.3

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 (used in) provided by operating activities	$	(0.1	)	$	106.6		$	77.0		$	29.1		$	(93.1	)	$	119.5
Cash (used in) provided by 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 proceeds (payments) from divestitures and asset sales		0.0			0.0			0.9			(4.7	)		0.0			(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			0.0
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) provided by 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 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

Description of Business - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018 Segment
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of operating segments	3

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Nov. 30, 2016
Summary Of Significant Accounting Policies [Line Items]
Equity method of investments						$ 0
Period for payment terms on ship and invoice arrangements.			45 days
Period for payment of approval basis sale			30 days
Percentage of LIFO inventory	53.00%	52.00%	53.00%	52.00%
Inventory write-down			$ 1,000,000	$ 400,000	$ 600,000
Goodwill impairment charge	$ 0	$ 0	$ 0	$ 0
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			50.00%
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 Asset Retirement Obligation Liabilities (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Asset Retirement Obligation Disclosure [Abstract]
Asset retirement obligation at beginning of year	$ 37.1	$ 36.0
Accretion expense	1.7	2.4
Revision in estimated cash flows (a)	0.8	9.4
Cash expenditures	(12.5)	(10.9)
Currency translation	(0.1)	0.2
Balance at end of period	$ 27.0	$ 37.1

Summary of Significant Accounting Policies - Summary of Asset Retirement Obligation Liabilities (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Charges related to restructuring activities	$ 1.8	$ 4.7

New Accounting Pronouncements - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Enacted corporate income tax rate	21.00%	35.00%	35.00%
Cost of goods sold	$ (1,375.1)	$ (1,153.4)	$ (1,126.2)
Selling, general and administrative expenses	$ (161.6)	$ (132.5)	(125.7)
Accounting Standards Update 2018-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Enacted corporate income tax rate	21.00%	35.00%
Reclassification of tax effects from AOCI		$ 3.2
ASU No. 2017-12 [Member]
Summary Of Significant Accounting Policies [Line Items]
Reclassification of unrealized gain from retained earnings to accumulated other comprehensive loss	$ 3.9
ASU No. 2017-07 [Member] \| Scenario, Adjustment [Member]
Summary Of Significant Accounting Policies [Line Items]
Cost of goods sold		0.7	1.7
Selling, general and administrative expenses		$ 0.8	$ 0.9
Accounting Standards Update 2016-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Finance lease, right-to-use Assets	115.0
Finance lease, liability	$ 130.0

Plant Closures and Discontinued Operations - Additional Information (Detail)	Dec. 31, 2016	Nov. 30, 2016	Mar. 31, 2016	Jul. 31, 2015
Discontinued Operations Disposed Of By Means Other Than Sale [Member] \| China [Member] \| Carbon Materials and Chemicals [Member]
Restructuring Cost And Reserve [Line Items]
Percentage of operations in Tangshan, China owned by the company			60.00%
Tangshan Koppers Kailuan Carbon Chemical Company Limited [Member]
Restructuring Cost And Reserve [Line Items]
Ownership percentage	30.00%	30.00%
KSA Limited Partnership [Member]
Restructuring Cost And Reserve [Line Items]
Ownership percentage				50.00%

Plant Closures and Discontinued Operations - Summary of Restructuring Activities and Related Reserves (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost And Reserve [Line Items]
Reserve, Beginning Balance	$ 18.3	$ 16.1
Accrual	4.9	14.6
Costs charged against assets	(2.1)	(6.3)
Reversal of accrued charges	(0.9)	(2.1)
Cash paid	(11.8)	(4.8)
Currency translation	(0.3)	0.8
Reserve, Ending Balance	8.1	18.3
Severance and Employee Benefits [Member]
Restructuring Cost And Reserve [Line Items]
Reserve, Beginning Balance	1.7	1.4
Accrual	0.0	0.9
Costs charged against assets	0.0	0.0
Reversal of accrued charges	0.0	(0.3)
Cash paid	0.0	(0.3)
Currency translation	0.0	0.0
Reserve, Ending Balance	1.7	1.7
Environmental Remediation [Member]
Restructuring Cost And Reserve [Line Items]
Reserve, Beginning Balance	2.7	1.5
Accrual	0.9	2.1
Costs charged against assets	0.0	0.0
Reversal of accrued charges	0.0	0.0
Cash paid	(3.4)	(1.1)
Currency translation	(0.2)	0.2
Reserve, Ending Balance	0.0	2.7
Asset Retirement [Member]
Restructuring Cost And Reserve [Line Items]
Reserve, Beginning Balance	10.6	10.0
Accrual	1.8	4.7
Costs charged against assets	0.0	0.0
Reversal of accrued charges	(0.9)	(1.8)
Cash paid	(7.9)	(2.4)
Currency translation	0.0	0.1
Reserve, Ending Balance	3.6	10.6
Other [Member]
Restructuring Cost And Reserve [Line Items]
Reserve, Beginning Balance	3.3	3.2
Accrual	2.2	6.9
Costs charged against assets	(2.1)	(6.3)
Reversal of accrued charges	0.0	0.0
Cash paid	(0.5)	(1.0)
Currency translation	(0.1)	0.5
Reserve, Ending Balance	$ 2.8	$ 3.3

Acquisitions - Additional Information (Detail) $ in Thousands			3 Months Ended								12 Months Ended
	Apr. 10, 2018 USD ($) Facility Yard	Feb. 28, 2018 USD ($) Facility	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Combined costs related to acquisitions											$ 6,500
Net sales			$ 425,400	$ 442,700	$ 436,000	$ 406,100	$ 366,100	$ 384,800	$ 378,000	$ 346,600	1,710,200	$ 1,475,500	$ 1,416,200
Income (loss) before taxes											54,800	60,300	$ 38,500
Koppers Utility and Industrial Products Inc. [Member]
Business Acquisition [Line Items]
Cash consideration	$ 201,300
Number of manufacturing facilities \| Facility	8
Number of distribution yards \| Yard	19
Revenues											142,000	147,000
Koppers Recovery Resources LLC [Member]
Business Acquisition [Line Items]
Cash consideration		$ 62,800
Revenues											21,000	$ 30,000
Number of processing facilities \| Facility		2
Koppers Utility and Industrial Products and Koppers Recovery Resources LLC [Member]
Business Acquisition [Line Items]
Net sales											163,000
Income (loss) before taxes											(4,200)
Inventory fair value purchase price accounting adjustments											$ 6,000

Acquisitions - Summary of Valuation of Identifiable Assets Acquired and Liabilities Assumed Upon Acquisition (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Apr. 10, 2018	Feb. 28, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill	$ 296.5			$ 188.2	$ 186.4
Koppers Utility and Industrial Products Inc. [Member]
Business Acquisition [Line Items]
Cash and cash equivalents		$ 1.5
Accounts receivable		20.2
Inventory		43.1
Other current assets		1.2
Property, plant and equipment		19.6
Intangible assets, net		59.4
Goodwill		77.1
Other non-current assets		0.2
Total assets acquired		222.3
Accounts payable and accrued liabilities		18.7
Other non-current liabilities		0.8
Net assets acquired		$ 202.8
Koppers Recovery Resources LLC [Member]
Business Acquisition [Line Items]
Cash and cash equivalents			$ 3.2
Accounts receivable			4.9
Inventory			0.0
Other current assets			0.3
Property, plant and equipment			6.6
Intangible assets, net			19.3
Goodwill			34.0
Other non-current assets			0.0
Total assets acquired			68.3
Accounts payable and accrued liabilities			2.3
Other non-current liabilities			0.0
Net assets acquired			$ 66.0

Acquisitions - Schedule of Identifiable Intangible Assets Acquired (Detail) - USD ($) $ in Millions			12 Months Ended
	Apr. 10, 2018	Feb. 28, 2018	Dec. 31, 2018
Business Acquisition [Line Items]
Remaining Life			11 years 1 month 6 days
Customer Contracts [Member]
Business Acquisition [Line Items]
Remaining Life			12 years 3 months 18 days
Non-Compete Agreements [Member]
Business Acquisition [Line Items]
Remaining Life			6 years 9 months 18 days
Trademarks [Member]
Business Acquisition [Line Items]
Remaining Life			4 years
Koppers Utility and Industrial Products Inc. [Member]
Business Acquisition [Line Items]
Amount	$ 59.4
Koppers Utility and Industrial Products Inc. [Member] \| Customer Contracts [Member]
Business Acquisition [Line Items]
Amount	$ 58.2
Remaining Life	15 years
Koppers Utility and Industrial Products Inc. [Member] \| Non-Compete Agreements [Member]
Business Acquisition [Line Items]
Amount	$ 1.2
Remaining Life	5 years
Koppers Recovery Resources LLC [Member]
Business Acquisition [Line Items]
Amount		$ 19.3
Koppers Recovery Resources LLC [Member] \| Customer Contracts [Member]
Business Acquisition [Line Items]
Amount		$ 18.7
Remaining Life		15 years
Koppers Recovery Resources LLC [Member] \| Trademarks [Member]
Business Acquisition [Line Items]
Amount		$ 0.6
Remaining Life		2 years

Acquisitions - Summary of Revenue and Income from Continuing Operations (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Business Combinations [Abstract]
Pro forma revenue	$ 1,760.9	$ 1,622.5
Pro forma income from continuing operations attributable to Koppers	$ 29.0	$ 26.6
Pro forma income per share - continuing operations, Basic	$ 1.39	$ 1.28
Pro forma income per share - continuing operations, Diluted	$ 1.36	$ 1.21

Revenue Recognition - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Disaggregation Of Revenue [Line Items]
Effect on revenue	$ 425,400	$ 442,700	$ 436,000	$ 406,100	$ 366,100	$ 384,800	$ 378,000	$ 346,600	$ 1,710,200	$ 1,475,500	$ 1,416,200
Effect on cost of goods sold									1,375,100	1,153,400	$ 1,126,200
Accounting Standards Update 2014-09 [Member]
Disaggregation Of Revenue [Line Items]
Cumulative increase to opening balance of retained earnings					300					300
Impact of restatement on revenue not previously recognized					5,300					5,300
Impact of restatement on cost of goods sold not previously recognized					$ 5,000					$ 5,000
Effect on revenue									3,100
Effect on cost of goods sold									2,900
Accounting Standards Update 2014-09 [Member] \| Accounts Receivable
Disaggregation Of Revenue [Line Items]
Contract assets	$ 10,500								$ 10,500			$ 5,300

Revenue Recognition - Schedule of Revenue and Cost of Goods Sold Recognized Net Impact of Adopting Topic 606 Decrease in Sales and Cost of Sales (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation Of Revenue [Line Items]
Sales	$ 425,400	$ 442,700	$ 436,000	$ 406,100	$ 366,100	$ 384,800	$ 378,000	$ 346,600	$ 1,710,200	$ 1,475,500	$ 1,416,200
Cost of sales									1,375,100	1,153,400	1,126,200
RUPS [Member]
Disaggregation Of Revenue [Line Items]
Sales									634,800	$ 512,600	$ 586,500
Accounting Standards Update 2014-09 [Member]
Disaggregation Of Revenue [Line Items]
Sales									3,100
Cost of sales									2,900
Accounting Standards Update 2014-09 [Member] \| Difference between Revenue Guidance in Effect before and after Topic 606 \| RUPS [Member]
Disaggregation Of Revenue [Line Items]
Sales									(2,200)
Cost of sales									$ (2,100)

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, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Net income attributable to Koppers	$ (2.6)	$ 7.6	$ 0.6	$ 17.8	$ (14.8)	$ 19.8	$ 19.7	$ 4.4	$ 23.4	$ 29.1	$ 29.3
Income (loss) from discontinued operations									0.4	(0.8)	0.6
Income from continuing operations attributable to Koppers									$ 23.0	$ 29.9	$ 28.7
Weighted average common shares outstanding:
Basic									20,871	20,754	20,636
Effect of dilutive securities									455	1,246	419
Diluted									21,326	22,000	21,055
Earnings per common share – continuing operations:
Basic earnings per common share	$ (0.13)	$ 0.36	$ 0.01	$ 0.86	$ (0.73)	$ 0.96	$ 1.00	$ 0.21	$ 1.10	$ 1.44	$ 1.39
Diluted earnings per common share	$ (0.13)	$ 0.35	$ 0.01	$ 0.81	$ (0.73)	$ 0.91	$ 0.95	$ 0.20	$ 1.08	$ 1.36	$ 1.36
Other data:
Antidilutive securities excluded from computation of diluted earnings per common share									401	156	415

Stock-based Compensation - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2015	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding		494,684		819,691
Future compensation expense related to non-vested stock-based compensation arrangements		$ 14.7
Future compensation expense, weighted-average expected period of recognition in months		25 months
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding		223,561		238,140
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] \| Employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards, vesting period		4 years
Restricted Stock Units (RSUs) [Member] \| Employee [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards, vesting period		2 years
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Percentage	200.00%
Number of shares outstanding		271,123		581,551
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 and 2017 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] \| Maximum [Member] \| March 2016 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target award earned by participants			200.00%
Performance Stock Units [Member] \| Maximum [Member] \| March 2016 and 2017 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target award earned by participants		200.00%
Performance Stock Units [Member] \| Minimum [Member] \| March 2016 Grant [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] \| Minimum [Member] \| March 2016 and 2017 Grant [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] \| Target Shares [Member] \| 2016 - 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Percentage		13.00%
Number of shares outstanding		254,036
Employee Stock Option [Member] \| Grants in March 2015 and Thereafter [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 \| Grants in March 2015 and Thereafter [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards, vesting period		4 years

Stock-based Compensation - Performance Award Fair Value Assumptions (Detail)	12 Months Ended
	Dec. 31, 2018 $ / shares
May 2018 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of performance award	$ 39.10
Expected dividend yield per share	0.00%
Expected volatility	37.05%
Risk-free interest rate	2.82%
Grant date fair value per share of performance award	$ 15.48
May 2018 Grant [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of performance award	$ 39.10
Expected dividend yield per share	0.00%
Expected volatility	39.40%
Risk-free interest rate	2.35%
Look-back period in years	2 years 10 months 2 days
Grant date fair value per share of performance award	$ 44.29
March 2017 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of performance award	$ 44.10
Expected dividend yield per share	0.00%
Expected volatility	39.70%
Risk-free interest rate	2.13%
Grant date fair value per share of performance award	$ 17.90
March 2017 Grant [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of performance award	$ 44.10
Expected dividend yield per share	0.00%
Expected volatility	43.50%
Risk-free interest rate	1.54%
Look-back period in years	2 years 9 months 29 days
Grant date fair value per share of performance award	$ 64.02
March 2018 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of performance award	$ 41.60
Expected dividend yield per share	0.00%
Expected volatility	37.05%
Risk-free interest rate	2.67%
Grant date fair value per share of performance award	$ 16.38
March 2018 Grant [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of performance award	$ 41.60
Expected dividend yield per share	0.00%
Expected volatility	39.40%
Risk-free interest rate	2.38%
Look-back period in years	2 years 10 months 2 days
Grant date fair value per share of performance award	$ 47.12
March 2016 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
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	1.45%
Grant date fair value per share of performance award	$ 7.41
March 2016 Grant [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
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 years 10 months 2 days
Grant date fair value per share of performance award	$ 23.70

Stock-based Compensation - Summary of Performance Stock Units (Detail) - shares	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	494,684	819,691
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	271,123	581,551
Minimum [Member] \| 2017 - 2019 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	0
Minimum [Member] \| 2018 - 2020 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	0
Target Shares [Member] \| 2017 - 2019 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	110,262
Target Shares [Member] \| 2018 - 2020 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	128,093
Maximum [Member] \| 2017 - 2019 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	220,524
Maximum [Member] \| 2018 - 2020 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	256,186

Stock-based Compensation - Summary of Status and Activity of Non-Vested Stock Awards (Detail)	12 Months Ended
	Dec. 31, 2018 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested, Beginning Balance	819,691
Granted	256,298
Performance share adjustment	(16,402)
Vested	(528,704)
Forfeited	(36,199)
Non-vested, Ending Balance	494,684
Beginning Balance, Non-vested, Weighted Average Grant Date Fair Value per Unit \| $ / shares	$ 29.14
Granted, Weighted Average Grant Date Fair Value per Unit \| $ / shares	43.53
Performance share adjustment \| $ / shares	24.85
Vested, Weighted Average Grant Date Fair Value per Unit \| $ / shares	20.19
Forfeited, Weighted Average Grant Date Fair Value per Unit \| $ / shares	37.80
Ending Balance, Non-vested, Weighted Average Grant Date Fair Value per Unit \| $ / shares	$ 45.65
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested, Beginning Balance	238,140
Granted	121,947
Performance share adjustment	0
Vested	(118,972)
Forfeited	(17,554)
Non-vested, Ending Balance	223,561
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested, Beginning Balance	581,551
Granted	134,351
Performance share adjustment	(16,402)
Vested	(409,732)
Forfeited	(18,645)
Non-vested, Ending Balance	271,123

Stock-based Compensation - Stock Options Fair Value Assumptions (Detail)	12 Months Ended
	Dec. 31, 2018 $ / shares
May 2018 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of stock option award	$ 39.10
Expected dividend yield per share	0.00%
Expected life in years	5 years 8 months 23 days
Expected volatility	37.05%
Risk-free interest rate	2.82%
Grant date fair value per share of option awards	$ 15.48
March 2017 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of stock option award	$ 44.10
Expected dividend yield per share	0.00%
Expected life in years	5 years 9 months 7 days
Expected volatility	39.70%
Risk-free interest rate	2.13%
Grant date fair value per share of option awards	$ 17.90
March 2018 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of stock option award	$ 41.60
Expected dividend yield per share	0.00%
Expected life in years	5 years 8 months 23 days
Expected volatility	37.05%
Risk-free interest rate	2.67%
Grant date fair value per share of option awards	$ 16.38
March 2016 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of stock option award	$ 18.11
Expected dividend yield per share	0.00%
Expected life in years	5 years 11 months 15 days
Expected volatility	40.86%
Risk-free interest rate	1.45%
Grant date fair value per share of option awards	$ 7.41
March 2015 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of stock option award	$ 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 of option awards	$ 5.20

Stock-based Compensation - Summary of Status and Activity of Stock Options (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options, Outstanding at December 31, 2017 \| shares	942,537
Options, Granted \| shares	144,825
Options, Exercised \| shares	(79,055)
Options, Forfeited \| shares	(26,367)
Options, Outstanding at December 31, 2018 \| shares	981,940
Options, Exercisable at December 31, 2018 \| shares	642,092
Weighted Average Exercise Price per Option, Outstanding at December 31, 2017 \| $ / shares	$ 27.59
Weighted Average Exercise Price per Option, Granted \| $ / shares	41.50
Weighted Average Exercise Price per Option, Exercised \| $ / shares	26.37
Weighted Average Exercise Price per Option, Forfeited \| $ / shares	31.67
Weighted Average Exercise Price per Option, Outstanding at December 31, 2018 \| $ / shares	29.63
Weighted Average Exercise Price per Option, Exercisable at December 31, 2018 \| $ / shares	$ 29.03
Weighted Average Remaining Contractual Term, Outstanding at December 31, 2018	5 years 9 months 18 days
Weighted Average Remaining Contractual Term, Exercisable at December 31, 2018	4 years 6 months
Aggregate Intrinsic Value, Outstanding at December 31, 2018 \| $	$ 0
Aggregate Intrinsic Value, Exercisable at December 31, 2018 \| $	$ 0

Stock-based Compensation - Schedule of Stock-Based Compensation Expense Recognized (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock-based compensation expense recognized:
Less related income tax benefit	$ 3.1	$ 4.1	$ 3.6
Decrease in net income attributable to Koppers	9.4	6.5	5.3
Intrinsic value of exercised stock options	1.1	1.3	0.1
Cash received from the exercise of stock options	2.9	2.7	0.4
Selling, General and Administrative Expenses [Member]
Stock-based compensation expense recognized:
Stock-based compensation expense	$ 12.5	$ 10.6	$ 8.9

Segment Information - Additional Information (Detail) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) Segment	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments \| Segment									3
Net sales	$ 425,400	$ 442,700	$ 436,000	$ 406,100	$ 366,100	$ 384,800	$ 378,000	$ 346,600	$ 1,710,200	$ 1,475,500	$ 1,416,200
Non-U.S. Countries [Member]
Segment Reporting Information [Line Items]
Net sales									$ 716,600	$ 623,300	$ 486,900

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

3 Months Ended

12 Months Ended

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2017

Sep. 30, 2017

Jun. 30, 2017

Mar. 31, 2017

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

$ 425,400

$ 442,700

$ 436,000

$ 406,100

$ 366,100

$ 384,800

$ 378,000

$ 346,600

$ 1,710,200

$ 1,475,500

$ 1,416,200

50,800

49,800

52,900

$ 13,600

$ 31,200

$ 22,300

$ 43,300

$ 13,600

$ 43,800

$ 38,100

$ 28,100

110,400

123,600

93,400

Railroad and Utility Products and Services [Member]

109,700

67,500

49,900

Carbon Materials and Chemicals [Member]

634,800

512,600

586,500

Performance Chemicals [Member]

655,400

551,700

436,300

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

420,000

411,200

393,400

634,800

512,600

586,500

17,700

11,800

11,900

^[1]

5,900

26,200

54,100

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

19,200

10,600

11,200

655,400

551,700

436,300

^[2]

15,300

20,100

22,300

^[3]

70,700

28,000

(22,600)

Operating Segments [Member] | Performance Chemicals [Member]

73,500

39,700

29,500

420,000

411,200

393,400

17,800

17,900

18,700

36,200

71,400

63,500

15,100

15,400

7,900

Intersegment [Member]

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

88,100

86,300

98,300

Intersegment [Member] | Performance Chemicals [Member]

77,300

79,600

90,200

Corporate, Non-Segment [Member]

10,800

6,700

8,100

^[4]

(2,400)

(2,000)

(1,600)