0001564590-21-007979 | 10-K | XBRL Viewer

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Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2020	Jan. 29, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Trading Symbol	KOP
Entity Registrant Name	KOPPERS HOLDINGS INC.
Entity Central Index Key	0001315257
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		21,098,544
Entity Public Float			$ 386.9
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock
Security Exchange Name	NYSE
Entity File Number	1-32737
Entity Incorporation, State or Country Code	PA
Entity Tax Identification Number	20-1878963
Entity Address, Address Line One	436 Seventh Avenue
Entity Address, City or Town	Pittsburgh
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	15219
City Area Code	412
Local Phone Number	227-2001
Document Annual Report	true
Document Transition Report	false
ICFR Auditor Attestation Flag	true
Documents Incorporated by Reference	Portions of the registrant’s definitive Proxy Statement for the 2021 Annual Meeting of Shareholders are incorporated by reference into Part III of this Annual Report on Form 10-K.

Consolidated Statement of Operations - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Net sales	$ 1,669.1	$ 1,637.0	$ 1,562.7
Cost of sales	1,308.7	1,306.3	1,260.9
Depreciation and amortization	54.1	51.4	46.9
Loss on sale of assets	(0.0)	(0.0)	8.3
Impairment and restructuring charges	6.5	6.0	4.0
Selling, general and administrative expenses	143.1	148.3	158.2
Operating profit	156.7	125.0	84.4
Other income, net	2.3	0.4	0.9
Interest expense	48.9	61.7	54.1
Income from continuing operations before income taxes	110.1	63.7	31.2
Income tax provision	21.0	0.0	25.7
Income from continuing operations	89.1	63.7	5.5
(Loss) income from discontinued operations, net of tax benefit (expense) of $0.9, $(1.4) and $(0.7)	(3.9)	3.7	23.7
Gain on sale of discontinued operations, net of tax expense of $8.3	35.8	0.0	0.0
Net income	121.0	67.4	29.2
Net (loss) income attributable to noncontrolling interests	(1.0)	0.8	5.8
Net income attributable to Koppers	$ 122.0	$ 66.6	$ 23.4
Basic -
Continuing operations	$ 4.25	$ 3.09	$ 0.26
Discontinued operations	1.56	0.13	0.86
Earnings per basic common share	5.81	3.22	1.12
Diluted -
Continuing operations	4.17	3.03	0.26
Discontinued operations	1.54	0.13	0.84
Earnings per diluted common share	$ 5.71	$ 3.16	$ 1.10
Weighted average shares outstanding (in thousands):
Basic	20,992	20,665	20,871
Diluted	21,374	21,068	21,326

Consolidated Statement of Operations (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
(Loss) income from discontinued operations, net of tax benefit (expense)	$ 0.9	$ (1.4)	$ (0.7)
Tax expense on gain on sale of business	$ 8.3	$ 8.3	$ 8.3

- Definition

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

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+ Details

Consolidated Statement of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 121.0	$ 67.4	$ 29.2
Changes in other comprehensive income (loss):
Currency translation adjustment	22.8	(1.3)	(25.6)
Unrealized gain (loss) on cash flow hedges, net of tax (expense) benefit of $(12.6), $(4.1) and $10.0	41.2	8.7	(25.2)
Change in accounting standard	0.0	0.0	0.3
Unrecognized pension prior service benefit, net of tax benefit of $0.0, $0.0 and $0.1	(0.0)	(0.1)	(0.6)
Unrecognized pension net (loss) gain, net of tax benefit (expense) of $0.4, $(0.8) and $0.2	(1.1)	2.1	(0.5)
Total comprehensive income (loss)	183.9	76.8	(22.4)
Comprehensive income attributable to noncontrolling interests	0.1	0.6	5.0
Comprehensive income (loss) attributable to Koppers	$ 183.8	$ 76.2	$ (27.4)

Consolidated Statement of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Tax benefit (expense), unrealized gains on cash flow hedges	$ (12.6)	$ (4.1)	$ 10.0
Unrecognized pension prior service benefit, tax benefit	0.0	0.0	0.1
Tax benefit (expense), unrecognized pension net income	$ 0.4	$ (0.8)	$ 0.2

Consolidated Balance Sheet - USD ($)
$ in Millions

Dec. 31, 2020

Dec. 31, 2019

Assets

Cash and cash equivalents, including restricted cash (Note 4)

$ 38.5

$ 32.3

Accounts receivable, net of allowance of $2.6 and $2.6

175.1

161.7

Income tax receivable

1.2

1.1

Inventories, net

^[1]

295.8

288.5

Assets of discontinued operations held for sale

0.0

17.1

Derivative contracts

38.5

2.4

Other current assets

15.4

16.4

Total current assets

564.5

519.5

Property, plant and equipment, net

^[2]

409.1

358.8

Operating lease right-of-use assets

102.5

112.3

Goodwill

297.8

296.1

Intangible assets, net

149.8

168.4

Deferred tax assets

18.4

23.7

Non-current assets of discontinued operations held for sale

0.0

59.3

Non-current derivative contracts

31.9

4.1

Other assets

24.6

22.4

Total assets

1,598.6

1,564.6

Liabilities

Accounts payable

154.1

162.8

Accrued liabilities

106.7

89.3

Current operating lease liabilities

21.2

22.0

Current maturities of long-term debt

10.1

10.2

Liabilities of discontinued operations held for sale

0.0

11.9

Total current liabilities

292.1

296.2

Long-term debt

765.8

891.0

Accrued postretirement benefits

46.2

46.6

Deferred tax liabilities

21.3

6.8

Operating lease liabilities

81.3

91.5

Non-current liabilities of discontinued operations held for sale

0.0

25.1

Other long-term liabilities

45.9

48.7

Total liabilities

1,252.6

1,405.9

Commitments and contingent liabilities (Note 19)

Equity

Senior Convertible Preferred Stock, $0.01 par value per share; 10,000,000 shares authorized; no shares issued

0.0

Common Stock, $0.01 par value per share; 80,000,000 shares authorized; 23,688,347 and 23,321,087 shares issued

0.2

Additional paid-in capital

234.1

221.9

Retained earnings

215.8

93.8

Accumulated other comprehensive loss

(15.9)

(77.7)

Treasury stock, at cost, 2,589,803 and 2,515,925 shares

(92.5)

(90.9)

Total Koppers shareholders’ equity

341.7

147.3

Noncontrolling interests

4.3

11.4

Total equity

346.0

158.7

Total liabilities and equity

$ 1,598.6

$ 1,564.6

[1]	Net inventories excludes $10.6 million of assets of discontinued operations held for sale related to our KJCC business as of December 31, 2019
[2]	Net property, plant, and equipment excludes $56.6 million of assets of discontinued operations held for sale related to our KJCC business as of December 31, 2019.

Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Accounts receivable, allowance	$ 2.6	$ 2.6
Senior Convertible Preferred Stock, par value	$ 0.01	$ 0.01
Senior Convertible Preferred Stock, shares authorized	10,000,000	10,000,000
Senior Convertible Preferred Stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common Stock, shares authorized	80,000,000	80,000,000
Common Stock, shares issued	23,688,347	23,321,087
Treasury stock, shares	2,589,803	2,515,925

Consolidated Statement of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash provided by (used in) operating activities:
Net income	$ 121.0	$ 67.4	$ 29.2
Adjustments to reconcile net cash provided by (used in) operating activities:
Depreciation and amortization	54.1	55.1	50.8
Stock-based compensation	11.3	12.1	12.5
Change in derivative contracts	(9.2)	(4.1)	6.9
Non-cash interest expense	2.6	2.6	2.4
(Gain) on sale of discontinued operations and loss on disposal of assets and investment	(35.6)	0.8	0.7
Insurance proceeds	(0.7)	(3.0)	(1.5)
Loss on sale of assets	(0.0)	(0.0)	8.3
Deferred income taxes	9.4	(10.9)	9.1
Change in other liabilities	(8.6)	(18.4)	(22.6)
Other - net	(0.6)	(0.3)	(0.8)
Changes in working capital:
Accounts receivable	(11.5)	25.4	(7.7)
Inventories	8.7	(14.8)	(18.3)
Accounts payable	(25.3)	(3.1)	30.8
Accrued liabilities	8.5	3.9	(27.0)
Other working capital	3.0	2.6	5.5
Net cash provided by operating activities	127.1	115.3	78.3
Cash provided by (used in) investing activities:
Capital expenditures	(69.8)	(37.2)	(109.7)
Acquisitions, net of cash acquired	(0.0)	(0.0)	(264.0)
Insurance proceeds	0.7	3.0	1.5
Net cash provided by sale of discontinued operations and asset sales	74.7	0.4	(4.2)
Net cash provided by (used in) investing activities	5.6	(33.8)	(376.4)
Cash (used in) provided by financing activities:
Net (decrease) increase in credit facility borrowings	(57.3)	(61.1)	234.9
Borrowings of long-term debt	0.0	0.0	100.0
Repayments of long-term debt	(70.7)	(29.7)	(20.3)
Issuances of Common Stock	1.1	4.0	2.9
Repurchases of Common Stock	(1.6)	(0.9)	(31.8)
Payment of debt issuance costs	(0.2)	(1.0)	(2.9)
Net cash (used in) provided by financing activities	(128.7)	(88.7)	282.8
Effect of exchange rate changes on cash	1.5	(0.4)	(4.4)
Change in cash and cash equivalents of discontinued operations held for sale	0.7	2.5	6.2
Net increase (decrease) in cash and cash equivalents	6.2	(5.1)	(13.5)
Cash and cash equivalents at beginning of period	32.3	37.4	50.9
Cash and cash equivalents at end of period	38.5	32.3	37.4
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash outflow from operating leases	31.5	31.1
Supplemental disclosure of non-cash investing and financing activities:
Right-of-use assets obtained in exchange for new operating lease liabilities	8.6	29.9
Cash paid during the year for:
Interest	50.1	60.9	49.8
Income taxes	13.4	16.8	25.9
Noncash investing activities:
Accrued capital expenditures	$ 8.9	$ 0.4	$ 3.7

Consolidated Statement of Shareholders' Equity - USD ($) $ in Millions	Total	Senior Convertible Preferred Stock [Member]	Common Stock [Member]	Noncontrolling Interests [Member]	Retained Earnings (Accumulated Deficit) [Member]	Currency Translation Adjustment [Member]	Unrecognized Gains (Losses) on Cash Flow Hedges [Member]	Unrecognized Pension Prior Service Cost [Member]	Unrecognized Pension Net Loss [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Koppers Shareholder's Equity (Deficit) [Member]
Balance at Dec. 31, 2017		$ 0.0	$ 0.2	$ 5.9	$ 7.4	$ (13.8)	$ 15.8	$ 0.0	$ (42.1)	$ 190.6	$ (58.2)
Net (loss) income attributable to noncontrolling interests	$ 5.8			5.8
Net income (loss) attributable to Koppers	23.4				23.4
Change in accounting standard, net of tax expense of $0.0, $1.3 and $0.0					(3.6)		3.9
Purchases											(31.8)
Change in currency translation adjustment	(25.6)			(0.9)		(24.7)
Reclassification of unrealized (gains) losses on cash flow hedges toexpense, net of tax benefit (expense) of $0.1, $(1.5) and $2.5							(7.4)
Change in cash flow hedges, net of tax (expense) benefitof $(12.7), $(2.6) and $7.5	(25.2)						(17.8)
Revaluation of unrecognized prior service benefit,net of tax benefit of $0.0, $0.1 and $0.0								(0.6)
Reclassification of unrecognized pension net loss to expense, netof tax expense of $0.3, $0.3 and $0.4									1.1
Revaluation of unrecognized pension net loss, net of tax(benefit) expense of $(0.7), $0.4 and $(0.5)									(1.6)
Sale of discontinued operations				(0.0)
Employee stock plans										12.5
Issuance of common stock										2.9
Balance at Dec. 31, 2018	67.0	0.0	0.2	10.8	27.2	(38.5)	(5.5)	(0.6)	(42.6)	206.0	(90.0)	$ (87.2)	$ 56.2
Net (loss) income attributable to noncontrolling interests	0.8			0.8
Net income (loss) attributable to Koppers	66.6				66.6
Change in accounting standard, net of tax expense of $0.0, $1.3 and $0.0					0.0		0.0
Purchases											(0.9)
Change in currency translation adjustment	(1.3)			(0.2)		(1.3)
Reclassification of unrealized (gains) losses on cash flow hedges toexpense, net of tax benefit (expense) of $0.1, $(1.5) and $2.5							4.6
Change in cash flow hedges, net of tax (expense) benefitof $(12.7), $(2.6) and $7.5	8.7						4.1
Revaluation of unrecognized prior service benefit,net of tax benefit of $0.0, $0.1 and $0.0								0.0
Reclassification of unrecognized pension net loss to expense, netof tax expense of $0.3, $0.3 and $0.4									1.1
Revaluation of unrecognized pension net loss, net of tax(benefit) expense of $(0.7), $0.4 and $(0.5)									1.0
Sale of discontinued operations				(0.0)
Employee stock plans										12.1
Issuance of common stock										3.8
Balance at Dec. 31, 2019	158.7	$ 0.0	$ 0.2	11.4	93.8	(39.8)	3.2	(0.6)	(40.5)	221.9	(90.9)	(77.7)	147.3
Net (loss) income attributable to noncontrolling interests	(1.0)			(1.0)
Net income (loss) attributable to Koppers	122.0				122.0
Change in accounting standard, net of tax expense of $0.0, $1.3 and $0.0					0.0		0.0
Purchases											(1.6)
Change in currency translation adjustment	22.8			1.1		21.7
Reclassification of unrealized (gains) losses on cash flow hedges toexpense, net of tax benefit (expense) of $0.1, $(1.5) and $2.5							(0.2)
Change in cash flow hedges, net of tax (expense) benefitof $(12.7), $(2.6) and $7.5	41.2						41.4
Revaluation of unrecognized prior service benefit,net of tax benefit of $0.0, $0.1 and $0.0								0.0
Reclassification of unrecognized pension net loss to expense, netof tax expense of $0.3, $0.3 and $0.4									1.1
Revaluation of unrecognized pension net loss, net of tax(benefit) expense of $(0.7), $0.4 and $(0.5)									(2.2)
Sale of discontinued operations				(7.2)
Employee stock plans										11.3
Issuance of common stock										0.9
Balance at Dec. 31, 2020	$ 346.0			$ 4.3	$ 215.8	$ (18.1)	$ 44.4	$ (0.6)	$ (41.6)	$ 234.1	$ (92.5)	$ (15.9)	$ 341.7

Consolidated Statement of Shareholders' Equity (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred losses on cash flow hedges, tax benefit (expense)	$ 12.6	$ 4.1	$ (10.0)
Revaluation of unrecognized pension net loss, tax benefit	(0.7)	0.4	(0.5)
Unrecognized Gains (Losses) on Cash Flow Hedges [Member]
Changes in accounting standard, tax	0.0	0.0	1.3
Unrealized (gains) losses on cash flow hedges to expense, tax benefit (expense)	0.1	(1.5)	2.5
Deferred losses on cash flow hedges, tax benefit (expense)	(12.7)	(2.6)	7.5
Unrecognized Pension Prior Service Cost [Member]
Revaluation of unrecognized prior service benefit, tax benefit	0.0	0.0	0.1
Unrecognized Pension Net Loss [Member]
Reclassification of unrecognized pension net loss, tax expense	$ 0.3	$ 0.3	$ 0.4

Description of Business

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Description of Business

1. Description of Business

Parent company of Koppers Inc. – In these financial statements, unless otherwise indicated or the context requires otherwise, when the terms “Koppers,” the “Company,” “we,” “our” or “us,” are used, they mean Koppers Holdings Inc. (“Koppers Holdings”) and its subsidiaries on a consolidated basis. The use of these terms is not intended to imply that Koppers Holdings and Koppers Inc. are not separate and distinct legal entities from each other and from their respective subsidiaries. Koppers Holdings has no direct operations and no significant assets other than the stock of Koppers Inc. It depends on the dividends from the earnings of Koppers Inc. and its subsidiaries to generate the funds necessary to meet its financial obligations. The terms of Koppers Inc.’s 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 – We are 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. Our business is operated through three business segments, Railroad and Utility Products and Services (“RUPS”), Performance Chemicals (“PC”) and Carbon Materials and Chemicals (“CMC”).

Our RUPS 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 and utility poles.

Our PC 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.

Our CMC 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, 2020

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Basis of presentation – The consolidated financial statements include our accounts and all majority-owned subsidiaries for which we are deemed to exercise control over its operations. All significant intercompany transactions have been eliminated in consolidation. Certain prior period amounts in the Notes to 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, we adopted Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers, using the modified retrospective method. We recognized the cumulative effect of initially applying the new revenue standard as an adjustment to the opening balance of retained earnings.

Revenue is recognized upon the completion of performance obligations under our contracts with customers and when control of a good or service is transferred to the customer. Substantially all of our contracts with customers are ship and invoice arrangements where revenue is recognized when we complete our performance obligations and transfer control to the customer. Revenue recognition generally occurs at the point of shipment; however in certain circumstances as shipping terms dictate, we transfer 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.

We recognize revenue related to the procurement of certain untreated railroad crossties upon delivery to our 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.

Contract Balances – The timing of revenue recognition in accordance with ASC 606 results in both billed accounts receivable and unbilled receivables, both classified as accounts receivable, net of allowance within the consolidated balance sheet. Contract assets of $5.8 million and $5.1 million are recorded within accounts receivable, net of allowance within the consolidated balance sheet as of December 31, 2020 and December 31, 2019, respectively.

Cash, cash equivalents and restricted cash – 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. Restricted cash of $2.3 million as of December 31, 2020 is being held in an escrow account for a remaining period of 15 months to cover potential customary indemnity claims by the buyers of one of our businesses sold as described in Note 4 – “Plant Closures and Discontinued Operations.”

Accounts receivable – We maintain allowances for doubtful accounts for estimated losses resulting from the inability of customers to make required payments. In circumstances where we become 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 our 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 net realizable value. UIP inventories are valued at the lower of cost, utilizing the moving average cost basis, or net realizable value. 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 51 percent of the FIFO inventory value at December 31, 2020 and 2019, respectively. In 2020, 2019 and 2018, we recorded inventory write-downs of $0.6 million, $1.0 million and $1.0 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 ten to 20 years and depreciable lives for machinery and equipment generally range from three 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.

We periodically evaluate whether current facts and circumstances indicate that the carrying value of 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. Goodwill is not amortized and is subject to an impairment test that we conduct annually or more frequently if a change in circumstances or the occurrence of events indicates that potential impairment exists. We perform an assessment of goodwill at the reporting unit level, utilizing a combination of an income approach, using a discounted cash flow methodology, and a market approach, by comparing the estimated fair value calculations of each reporting unit with its net book value. The discounted cash flow calculations are dependent on several subjective factors including the timing of future forecasted cash flows including future forecasted revenue growth rates, and the discount rate. If assumptions or estimates in the fair value calculations change or if future forecasted cash flows or future forecasted growth rates vary from what was planned, this may impact the impairment analysis. We performed an impairment test for goodwill for each of the reporting units using the above quantitative testing approach. Based on the evaluations performed, we determined that the fair value of each of the reporting units exceeded its carrying amount, and therefore, we determined that goodwill was not impaired.

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

Leases – Effective January 1, 2019, we changed our method of accounting for leases due to the adoption of Accounting Standards Update (ASU) No. 2016-02, “Leases (Topic 842)” and ASU No. 2018-10, “Codification Improvements to Topic 842, Leases”, using the modified retrospective method with no restatement of comparative periods presented. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods.

Lease arrangements are determined whether or not to be a lease at inception. Right-of-use (“ROU”) assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments. ROU lease liabilities are recognized based on the present value of the future minimum lease payments over the term of the lease as of the start date and may include consideration of certain adjustments including non-lease components. ROU assets are determined based on the determined ROU lease liability and may include the consideration of certain adjustments including initial direct costs, prepaid lease payments, lease incentives received, and non-lease components. The option to extend or terminate a lease is included in the determination of the ROU asset and lease liability only when it is reasonably certain that we will exercise that option.

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.

We recognize 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 our asset retirement obligation liabilities:

	December 31,
	2020			2019
(Dollars in millions)
Asset retirement obligation at beginning of year	$	20.7		$	27.0
Accretion expense		1.1			1.5
Revision in estimated cash flows ^(a)		4.6			4.7
Cash expenditures		(6.6	)		(12.5	)
Balance at end of period	$	19.8		$	20.7

(a) Revision in estimated cash flows for 2020 and 2019 includes $2.9 and $3.4 million of charges related to restructuring activities, respectively. See Note 4 – “Plant Closures and Discontinued Operations” for additional information.

Litigation and contingencies – Amounts associated with litigation and contingencies are accrued when management, after taking into consideration the facts and circumstances of each matter including any settlement offers, has determined that it is probable that a liability has been incurred and the amount of loss can be reasonably estimated. Legal costs for litigation are expensed as incurred with the exception of legal fees relating to the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, as amended (“CERCLA”), sites.

Environmental liabilities – We accrue 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.

COVID-19 Assessment

In March 2020, the World Health Organization categorized the current coronavirus disease (“COVID-19”) as a pandemic. COVID-19 continues to impact the United States and other countries across the world, and the duration and ultimate severity of its effects are currently unknown. This current level of uncertainty over the economic and operational impacts of COVID-19 means the related future financial impact cannot be reasonably estimated at this time. Our consolidated financial statements presented herein reflect certain estimates and assumptions made by management that affect the reported amounts of assets and liabilities and disclosure of such assets and liabilities at the date of the consolidated financial statements and reported amounts of revenue and expenses during the reporting periods presented.

Such estimates and assumptions affect, among other things, our goodwill, long-lived asset and intangible asset valuation; inventory valuation; valuation of deferred income taxes; and the allowance for doubtful accounts. Events and changes in circumstances arising after December 31, 2020, including those resulting from the impacts of COVID-19, will be reflected in management’s estimates for future periods.

New Accounting Pronouncements

12 Months Ended

Dec. 31, 2020

Accounting Changes And Error Corrections [Abstract]

New Accounting Pronouncements

3. New Accounting Pronouncements

In March 2020, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2020-04: Reference Rate Reform (Topic 848) Facilitation of the Effects of Reference Rate Reform on Financial Reporting. This update provides optional guidance for a limited period of time to ease potential accounting impacts associated with transitioning away from reference rates that are expected to be discontinued, such as the London Interbank Offered Rate (“LIBOR”). This ASU includes practical expedients for contract modifications due to reference rate reform and will not require remeasurement or reassessment of a previous accounting determination at the modification date. These practical expedients may be applied from March 12, 2020 through December 31, 2022. Our debt agreements include the use of alternate rates if LIBOR is not available and we do not expect the change from LIBOR to an alternate rate will have a material impact to our consolidated financial statements.

In January 2020, the FASB issued ASU No. 2020-01, “Investments – Equity Securities (Topic 321), Investments – Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815) – Clarifying the Interactions between Topic 321, Topic 323, and Topic 815.” This ASU is effective for fiscal years beginning after December 15, 2020. We do not expect the adoption of ASU No. 2020-01 to have a material impact on our consolidated financial statements.

In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” ASU No. 2016-13 replaces the incurred loss impairment methodology with a methodology that reflects expected credit losses. We adopted ASU No. 2016-13 as of January 1, 2020 and there was no material impact on our financial statements.

- Definition

The entire disclosure for change in accounting principle. Includes, but is not limited to, nature, reason, and method of adopting amendment to accounting standards or other change in accounting principle.

+ References

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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Plant Closures and Discontinued Operations

12 Months Ended

Dec. 31, 2020

Discontinued Operations And Disposal Groups [Abstract]

Plant Closures and Discontinued Operations

4. Plant Closures and Discontinued Operations

Over the past six years, we have been restructuring our Carbon Materials and Chemicals (“CMC”) segment in order to concentrate our facilities in regions where we believe we hold key competitive advantages to better serve our global customers. These closure activities include:

	•	In February 2021, we completed the sale of our Follansbee, West Virginia coal tar distillation facility. In August 2019, we ceased remaining production activities at the facility. Previously in 2018, we had ceased naphthalene refining activities at the facility subsequent to the commissioning of a new naphthalene refining plant in Stickney, Illinois.
	•	In September 2020, we sold Koppers (Jiangsu) Carbon Chemical Company Limited (“KJCC”).
	•	In September 2018, we sold our U.K.-based specialty chemicals business.
	•	In November 2016, we sold our 30-percent interest in Tangshan Kailuan Koppers Carbon Chemical Company Limited (“TKK”) located in the Hebei Province in China.
	•	In July 2016, we discontinued coal tar distillation activities at our CMC plant located in Clairton, Pennsylvania. In October 2018, we completed the sale of the facility.
	•	In March 2016, we discontinued production at our 60-percent owned CMC plant located in Tangshan, China.
	•	In February 2016, we ceased coal tar distillation and specialty pitch operations at both of our United Kingdom CMC facilities. In July 2016, we sold substantially all of our CMC tar distillation properties and assets in the United Kingdom.
	•	In April 2014, we ceased coal tar distillation activities at our CMC facility located in Uithoorn, the Netherlands.

Other closure and divestiture activity relates to our Railroad Utility Products and Services (“RUPS”) segment. These activities include:

	•	In June 2020, we announced the closure of a crosstie treating plant located in Denver, Colorado and in the third quarter of 2020 we discontinued production activities at this location.
	•	In August 2019, we sold our utility pole treatment plant located in Blackstone, Virginia.
	•	In August 2015, we closed a crosstie treating plant located in Green Spring, West Virginia.
	•	In July 2015, we sold the assets of our 50-percent interest in KSA Limited Partnership, a concrete crosstie manufacturer.

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

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

	Severance and employee benefits			Asset retirement			Other			Total
(Dollars in millions)
Reserve at December 31, 2018	$	1.7		$	3.6		$	2.8		$	8.1
Accrual		0.0			3.4			3.0			6.4
Costs charged against assets		0.0			0.0			(3.0	)		(3.0	)
Reversal of accrued charges		(0.3	)		(0.1	)		0.0			(0.4	)
Cash paid		(0.5	)		(6.2	)		(0.3	)		(7.0	)
Currency translation		0.0			0.0			(0.1	)		(0.1	)
Reserve at December 31, 2019	$	0.9		$	0.7		$	2.4		$	4.0
Accrual		0.5			2.9			3.4			6.8
Costs charged against assets		0.0			0.0			(3.4	)		(3.4	)
Reversal of accrued charges		(0.3	)		0.0			0.0			(0.3	)
Cash paid		(0.2	)		(0.8	)		(0.3	)		(1.3	)
Currency translation		0.0			0.0			0.2			0.2
Reserve at December 31, 2020	$	0.9		$	2.8		$	2.3		$	6.0

On September 30, 2020, we sold KJCC to Fangda Carbon New Material Co., Ltd and C-Chem Co., Ltd., a subsidiary of Nippon Steel Chemical & Material Co., Ltd. KJCC was located in Pizhou, Jiangsu Province, China and was a 75 percent-owned coal tar distillation company which was part of our CMC segment. The sales price was $107.0 million, subject to adjustments for cash, debt and working capital as defined in the sale and purchase agreement. The pre-tax gain on the sale of KJCC was $44.1 million and the after-tax gain on the sale was $35.8 million. The estimated final net cash proceeds to Koppers will total $65.2 million, after payments for Chinese capital gain taxes, transaction costs and estimated working capital adjustments. Included in the cash proceeds is restricted cash of $2.3 million which is being held in an escrow account and is recorded within Cash and Cash Equivalents as of December 31, 2020 to cover potential customary indemnity claims by the buyers for a remaining period of 15 months. We have previously elected to include proceeds received from the sale of a subsidiary that is separately reported as a discontinued operation within cash flows from continuing operations on the Consolidated Statement of Cash Flows.

The sale of KJCC represented a strategic shift that has a major effect on our operations and financial results and was, therefore, classified as discontinued operations in our consolidated financial statements and notes, which have been restated accordingly.

Net sales and operating (loss) profit from discontinued operations for the years ended December 31, 2020, 2019 and 2018 consist of the following amounts:

	Year Ended December 31,
	2020			2019		2018
(Dollars in millions)
Net sales	$	31.6		$	135.8	$	147.5
Operating (loss) profit		(5.0	)		5.8		26.0

The cash flows related to KJCC have not been restated in the Consolidated Statement of Cash Flows. Net cash inflows and outflows from discontinued operations for the years ended December 31, 2020, 2019 and 2018 consist of the following amounts:

	Year Ended December 31,
	2020			2019			2018
(Dollars in millions)
Net cash provided by operating activities	$	0.7		$	21.4		$	10.4
Net cash used in investing activities		(0.9	)		(3.8	)		(3.3	)
Net cash used in financing activities		0.0			(19.8	)		(12.6	)
Effect of exchange rate changes on cash		(0.5	)		(0.3	)		(0.7	)
Net decrease in cash and cash equivalents		(0.7	)		(2.5	)		(6.2	)

Assets of Discontinued Operations Held for Sale

Assets and liabilities are classified as held for sale when, among other items, the sale of the asset is probable and the completed sale is expected to occur within one year. Upon classification as held for sale, such assets are no longer depreciated or depleted, and a measurement for impairment is performed to determine if there is any excess of carrying value over fair value less costs to sell.

The agreement to sell KJCC met all of the criteria to classify its assets and liabilities as held for sale in the first quarter of 2020 and as part of the required evaluation under the held for sale guidance, we determined that the approximate fair value less costs to sell the operations exceeded the carrying value of the net assets and no impairment charge was recorded.

The below amounts are excluded from the respective balance sheet footnotes as of December 31, 2019. We have incurred aggregated transactions costs related to this divestiture of $4.9 million during the year ended December 31, 2020, which are included in (loss) income from discontinued operations and gain on the sale of discontinued operations on the Consolidated Statement of Operations.

The following represents the carrying amount of assets and liabilities, by major class, classified as held for sale on the Consolidated Balance Sheet as of December 31, 2019:

	December 31, 2019
(Dollars in millions)
Assets
Cash and cash equivalents	$	0.7
Accounts receivable		2.2
Income tax receivable		0.8
Inventories, net		10.6
Other current assets		2.8
Total current assets held for sale		17.1
Property, plant and equipment, net		56.6
Operating lease right-of-use assets		1.2
Other assets		1.5
Total non-current assets held for sale		59.3
Total assets held for sale	$	76.4
Liabilities
Accounts payable	$	7.1
Accrued liabilities		4.7
Current operating lease liabilities		0.1
Total current liabilities held for sale		11.9
Deferred tax liabilities		0.6
Operating lease liabilities		1.1
Other long-term liabilities		23.4
Total non-current liabilities held for sale		25.1
Total liabilities held for sale	$	37.0

Acquisitions

12 Months Ended

Dec. 31, 2020

Business Combinations [Abstract]

Acquisitions

5. Acquisitions

On April 10, 2018, Koppers Inc. acquired its Utility and Industrial Products business (“UIP”) for net cash consideration of $201.3 million. The transaction was funded by borrowings on Koppers Inc.’s Credit Facility discussed in “Note 15 - Debt.” UIP is a manufacturer of treated wood transmission and distribution poles for utility and cooperative utility companies. It is also a manufacturer of treated wood pilings used for construction applications. UIP manufactures and sells its treated wood poles and pilings through a network of manufacturing facilities and 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 our PC and CMC segments, respectively.

On February 28, 2018, Koppers Inc. acquired its Koppers Recovery Resources business (“KRR”) for net cash consideration of $62.8 million. The purchase price was funded by borrowings on Koppers Inc.’s Credit Facility. 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 are used as a substitute for conventional higher-cost carbon-based fuel.

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.

The following unaudited pro forma information presents a summary of our 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 our future financial results 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
(Dollars in millions)
Pro forma revenue	$	1,613.4
Pro forma income from continuing operations attributable to Koppers		5.7
Pro forma income per share - continuing operations:
Basic -	$	0.27
Diluted -	$	0.27

Fair Value Measurements

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Fair Value Measurements

6. Fair Value Measurements

Carrying amounts and the related estimated fair values of our financial instruments as of December 31, 2020 and 2019 are as follows:

	December 31, 2020				December 31, 2019
	Fair Value		Carrying Value		Fair Value		Carrying Value
(Dollars in millions)
Financial assets:
Investments and other assets	$	1.2	$	1.2	$	1.2	$	1.2
Financial liabilities:
Long-term debt (including current portion)	$	799.2	$	784.2	$	906.9	$	911.9

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 our long-term debt is estimated based on the market prices for the same or similar issuances or on the current rates offered to us for debt of the same remaining maturities (Level 2). The fair value of our Credit Facility approximates carrying value due to the variable rate nature of this instrument.

Earnings per Common Share

12 Months Ended

Dec. 31, 2020

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,
	2020			2019		2018
(Dollars in millions, except share amounts, in thousands, and per share amounts)
Net income attributable to Koppers	$	122.0		$	66.6	$	23.4
Less: (Loss) income from discontinued operations		(3.9	)		3.7		23.7
Gain on sale of discontinued operations		35.8			0.0		0.0
Plus: Non-controlling (loss) income		(1.0	)		0.8		5.8
Income from continuing operations attributable to Koppers	$	89.1		$	63.7	$	5.5
Weighted average common shares outstanding:
Basic		20,992			20,665		20,871
Effect of dilutive securities		382			403		455
Diluted		21,374			21,068		21,326
Earnings per common share – continuing operations:
Basic earnings per common share	$	4.25		$	3.09	$	0.26
Diluted earnings per common share		4.17			3.03		0.26
Other data:
Antidilutive securities excluded from computation of diluted earnings per common share		717			764		401

Stock-based Compensation

12 Months Ended

Dec. 31, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-based Compensation

8. Stock-based Compensation

We have outstanding stock-based compensation awards that were granted under the amended and restated 2005 Long-Term Incentive Plan (the “2005 LTIP”), the 2018 Long-Term Incentive Plan (the “2018 LTIP”) and the 2020 Long-Term Incentive Plan (the “2020 LTIP”). The 2005 LTIP, the 2018 LTIP and the 2020 LTIP are collectively referred to as the ”LTIP”. On May 6, 2020, the 2020 LTIP was approved by our shareholders and the 2018 LTIP was frozen. Similar to the 2018 LTIP, the 2020 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”). 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 is the market price of the underlying common stock on the date of grant and the fair value of performance stock units is determined using a Monte Carlo valuation model. 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.

Performance stock units have vesting based upon a market condition. These performance stock units have multi-year performance objectives and a three-year period for vesting (if the applicable performance objective is achieved). The applicable performance objective is based on our 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. We have the discretion to settle the award in cash rather than shares, although we currently expect that all awards will be settled by the issuance of shares.

We calculated the fair value of the performance stock unit awards on the date of the grant using assumptions listed below:

	March 2020 Grant			March 2019 Grant			May 2018 Grant			March 2018 Grant
Grant date price per share of performance award	$	19.63		$	26.63		$	39.10		$	41.60
Expected dividend yield per share		0.00	%		0.00	%		0.00	%		0.00	%
Expected volatility		45.60	%		39.00	%		39.40	%		39.40	%
Risk-free interest rate		0.72	%		2.50	%		2.35	%		2.38	%
Look-back period in years		2.83			2.82			2.84			2.84
Grant date fair value per share of performance award	$	11.56		$	40.30		$	44.29		$	47.12

Dividends declared, if any, on our 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, 2020:

Performance Period	Minimum Shares		Target Shares		Maximum Shares
2018 – 2020		0		3,048		6,096
2019 – 2021		0		234,597		281,536
2020 – 2022		0		154,099		308,198

Performance stock units granted in March 2018 for the 2018 – 2020 performance period did not meet the minimum performance criteria and will not vest in March 2021.

The following table shows a summary of the status and activity of non-vested stock awards for the year ended December 31, 2020:

	Restricted Stock Units			Performance Stock Units			Total Stock Units			Weighted Average Grant Date Fair Value per Unit
Non-vested at January 1, 2020		343,012			445,186			788,198		$	40.18
Granted		369,161			232,481			601,642		$	15.86
Performance share adjustment		0			(150,464	)		(150,464	)	$	30.68
Vested		(168,534	)		(110,168	)		(278,702	)	$	41.68
Forfeited		(34,130	)		(25,291	)		(59,421	)	$	33.86
Non-vested at December 31, 2020		509,509			391,744			901,253		$	25.48

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

	March 2020 Grant			March 2019 Grant			March 2018 Grant			March 2017 Grant
Grant date price per share of stock option award	$	19.63		$	26.63		$	41.60		$	44.10
Expected dividend yield per share		0.00	%		0.00	%		0.00	%		0.00	%
Expected life in years		6.40			6.14			5.73			5.77
Expected volatility		42.85	%		39.44	%		37.05	%		39.70	%
Risk-free interest rate		0.87	%		2.53	%		2.67	%		2.13	%
Grant date fair value per share of option awards	$	8.42		$	11.29		$	16.38		$	17.90

We do 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 us. Expected volatility is based on the historical volatility of our 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, 2020:

	Options			Weighted Average Exercise Price per Option		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in millions)
Outstanding at December 31, 2019		966,849		$	28.45
Granted		187,701		$	19.63
Exercised		(2,500	)	$	20.00
Expired		(5,129	)	$	31.28
Forfeited		(26,667	)	$	32.45
Outstanding at December 31, 2020		1,120,254		$	26.89		5.41	$	8.6
Exercisable at December 31, 2020		776,125		$	27.39		4.05	$	6.0

Stock Compensation Expense

Total stock-based compensation expense recognized under our LTIP and employee stock purchase plan for the three years ended December 31, 2020 are as follows:

	Year Ended December 31,
	2020		2019		2018
(Dollars in millions)
Stock-based compensation expense recognized:
Selling, general and administrative expenses	$	11.3	$	12.1	$	12.5
Less related income tax benefit		2.2		0.2		3.1
Decrease in net income attributable to Koppers	$	9.1	$	11.9	$	9.4
Intrinsic value of exercised stock options	$	0.0	$	1.1	$	1.1
Cash received from the exercise of stock options	$	0.0	$	2.9	$	2.9

As of December 31, 2020, total future compensation expense related to non-vested stock-based compensation arrangements totaled $14.6 million and the weighted-average period over which this expense is expected to be recognized is approximately 26 months.

Segment Information

12 Months Ended

Dec. 31, 2020

Segment Reporting [Abstract]

Segment Information

9. Segment Information

We have three reportable segments: Railroad and Utility Products and Services, Performance Chemicals and Carbon Materials and Chemicals. Our 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.

Our RUPS 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. 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.

Our CMC 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.

We evaluate performance and determine resource allocations based on a number of factors, including earnings before interest, taxes, depreciation and amortization (“EBITDA”) and operating profit or loss from operations. Operating profit does not include other loss, 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.

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

	Year Ended December 31,
	2020			2019			2018
(Dollars in millions)
Revenues from external customers:
Railroad and Utility Products and Services	$	759.1		$	733.5		$	634.8
Performance Chemicals		526.3			448.3			420.0
Carbon Materials and Chemicals^(a)		383.7			455.2			507.9
Total	$	1,669.1		$	1,637.0		$	1,562.7
Intersegment revenues:
Performance Chemicals	$	13.7		$	12.6		$	10.8
Carbon Materials and Chemicals		78.7			75.2			77.3
Total	$	92.4		$	87.8		$	88.1
Depreciation and amortization expense:
Railroad and Utility Products and Services	$	20.1		$	19.4		$	17.7
Performance Chemicals		18.1			18.3			17.8
Carbon Materials and Chemicals^(b)		15.9			13.7			11.4
Total	$	54.1		$	51.4		$	46.9
Operating profit (loss):
Railroad and Utility Products and Services^(c)	$	46.7		$	35.8		$	5.9
Performance Chemicals		88.6			52.1			36.2
Carbon Materials and Chemicals^(d)		23.4			39.2			44.7
Corporate^(e)		(2.0	)		(2.1	)		(2.4	)
Total	$	156.7		$	125.0		$	84.4
Capital expenditures (excluding acquisitions):
Railroad and Utility Products and Services	$	31.3		$	11.6		$	19.2
Performance Chemicals		12.1			9.7			15.1
Carbon Materials and Chemicals^(f)		24.8			15.5			73.5
Corporate		1.6			0.4			1.9
Total	$	69.8		$	37.2		$	109.7

(a)	Revenue excludes KJCC discontinued operations of $31.6 million, $135.8 million and $147.5 million for the years ended December 31, 2020, 2019 and 2018, respectively.

(b)	Depreciation and amortization expense excludes KJCC discontinued operations of $0.6 million, $3.7 million and $3.9 million for the years ended December 31, 2020, 2019 and 2018, respectively.

(c)	Includes $6.0 million of inventory fair value purchase price accounting adjustments from our acquisition of UIP in 2018.

(d)	Operating profit (loss) excludes KJCC discontinued operations of $(5.0) million, $5.8 million and $26.0 million for the years ended December 31, 2020, 2019 and 2018, respectively.

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

(f)	Capital expenditures includes KJCC discontinued operations of $0.6 million, $3.9 million and $3.4 million for the years ended December 31, 2020, 2019 and 2018, respectively.

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

	December 31,
	2020		2019
(Dollars in millions)
Segment assets:
Railroad and Utility Products and Services	$	583.1	$	562.2
Performance Chemicals		536.1		457.7
Carbon Materials and Chemicals		424.2		502.1
Segment assets		1,543.4		1,522.0
Cash and cash equivalents		0.4		0.0
Income tax receivable		1.2		1.9
Deferred taxes		28.8		17.0
Property, plant and equipment, net		5.9		5.3
Operating lease right-of-use assets		11.9		13.2
Prepaid insurance and other assets		7.0		5.2
Total^(a)	$	1,598.6	$	1,564.6
Goodwill:
Railroad and Utility Products and Services	$	121.1	$	120.7
Performance Chemicals		176.7		175.4
Total	$	297.8	$	296.1

(a)	The Carbon Materials and Chemicals segment includes $76.4 million of assets of discontinued operations held for sale related to our KJCC business at December 31, 2019.

Revenues and Long-lived Assets by Geographic Area

	Year		Revenue		Long-lived assets
(Dollars in millions)
United States		2020	$	1,170.1	$	832.0
		2019		1,141.2		796.0
		2018		993.5		732.1
Australasia		2020		194.3		82.0
		2019		199.6		76.6
		2018		218.8		69.8
Europe		2020		162.3		83.2
		2019		177.5		70.2
		2018		214.6		44.8
Other countries		2020		142.4		18.5
		2019		118.7		19.3
		2018		135.8		18.3
Total^(a)		2020	$	1,669.1	$	1,015.7
		2019	$	1,637.0	$	962.1
		2018	$	1,562.7	$	865.1

(a)

Revenue excludes KJCC discontinued operations of $31.6 million, $135.8 million and $147.5 million for the years ended December 31, 2020, 2019 and 2018, respectively. Long-lived assets exclude $59.3 million and $59.0 million of assets of discontinued operations held for sale related to our KJCC business at December 31, 2019 and 2018, respectively.

Revenues by geographic area in the above table are attributed by the destination country of the sale. Revenues from non-U.S. countries totaled $499.0 million in 2020, $495.8 million in 2019 and $569.2 million in 2018.

Segment Revenues for Significant Product Lines

	Year Ended December 31,
	2020		2019		2018
(Dollars in millions)
Railroad and Utility Products and Services:
Railroad treated products	$	405.1	$	419.6	$	341.7
Utility poles		241.7		222.0		184.7
Railroad infrastructure services		63.5		36.5		36.9
Rail joints		20.3		26.8		33.5
Other products		28.6		28.6		38.0
		759.1		733.5		634.8
Performance Chemicals:
Wood preservative products		510.7		418.8		389.1
Other products		15.6		29.5		30.9
		526.3		448.3		420.0
Carbon Materials and Chemicals:
Pitch and related products		230.9		272.4		280.9
Phthalic anhydride and other chemicals		66.4		77.9		84.6
Creosote and distillates		40.0		46.3		84.1
Naphthalene		19.7		24.9		26.2
Other products		26.7		33.7		32.1
		383.7		455.2		507.9
Total^(a)	$	1,669.1	$	1,637.0	$	1,562.7

(a)	Revenue excludes KJCC discontinued operations of $31.6 million, $135.8 million and $147.5 million for the years ended December 31, 2020, 2019 and 2018, respectively.

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Income Taxes

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Income Taxes

10. Income Taxes

Income Tax Provision

Components of our income tax provision are as follows:

	Year Ended December 31,
	2020		2019			2018
(Dollars in millions)
Current:
Federal	$	0.8	$	(3.5	)	$	(1.2	)
State		0.7		0.5			0.1
Foreign		11.1		14.4			17.9
Total current tax provision		12.6		11.4			16.8
Deferred:
Federal		6.1		3.1			9.6
State		1.6		0.4			(0.2	)
Foreign		0.7		(14.9	)		(0.5	)
Total deferred tax provision (benefit)		8.4		(11.4	)		8.9
Total income tax provision	$	21.0	$	0.0		$	25.7

Income before income taxes from foreign operations for 2020, 2019 and 2018 was $52.4 million, $69.9 million and $82.3 million, respectively.

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

	Year Ended December 31,
	2020			2019			2018
Federal income tax rate		21.0	%		21.0	%		21.0	%
GILTI inclusion, net of foreign tax credits		4.0			1.4			21.1
Foreign earnings taxed at different rates		2.9			(0.2	)		0.4
State income taxes, net of federal tax benefit		2.2			1.1			(5.9	)
Transition tax from Tax Act		0.0			0.0			27.3
Deferred tax adjustments from Tax Act		0.0			0.0			(12.0	)
Intra-entity transfer of intangible assets		0.0			(23.4	)		0.0
Change in tax contingency reserves		(0.2	)		(7.0	)		(3.5	)
Deferred tax adjustments		(2.2	)		0.0			4.0
Valuation allowance adjustments		(12.1	)		9.1			28.8
Other		3.5			(2.0	)		1.2
		19.1	%		0.0	%		82.4	%

In 2017, the Tax Cut and Jobs Act of 2017 (“Tax Act”) was enacted into law. The Tax Act included a number of key changes that have impacted our tax provision for each of the years in the three-year period ended December 31, 2020: a reduction in the U.S. corporate income tax rate to 21 percent from 35 percent, imposition of a one-time transition tax on certain unrepatriated earnings of foreign subsidiaries, imposition of a minimum tax on earnings of a foreign corporation (the global intangible low-taxed income tax or “GILTI tax”) and a limitation on our interest expense deduction.

Rate reduction – 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. During the year ended December 31, 2017, we initially recorded a charge to the carrying value of our deferred tax assets and liabilities in the United States upon enactment of the Tax Act. After further analysis and after the effect of filing our 2017 U.S. tax return, we revised this amount and recorded an income tax benefit of $3.8 million in the year ended December 31, 2018.

Transition tax – In the year ended December 31, 2017, we recorded an initial estimated charge related to the one-time transition tax. In the year ended December 31, 2018, we revised our original estimate and recorded additional income tax expense of $8.6 million as a result of additional guidance issued by the Internal Revenue Service. Due to the availability of net operating losses, our total cash payment for the one-time transition tax is approximately $5.1 million which is being paid in installments through 2024.

GILTI tax – We have recorded an income tax expense, net of foreign tax credits, of $4.4 million, $0.9 million and $6.6 million in the years ended December 31, 2020, 2019 and 2018, respectively. However, the impact of the GILTI tax did not result in any incremental cash tax payments in the years ended December 31, 2019 and 2018 since it was offset by available net operating losses.

Interest expense deduction limitation – As enacted in 2017, the interest expense deduction is limited to 30 percent of adjusted taxable income as defined under the tax regulations and any such limitation that is disallowed in a year can be carried forward to future years. In the years ended December 31, 2019 and 2018, we recorded a cumulative valuation allowance totaling $13.3 million for the disallowed interest expense deduction due to the uncertainly of when we could utilize the carryforward amounts.

During 2020, two events occurred which enabled us to adjust our interest expense limitations on our 2018 and 2019 U.S. tax returns. In March 2020, the Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”) was enacted and a provision of the CARES Act increased the allowable business interest expense deduction to 50 percent of adjusted taxable income retroactively to January 1, 2019. In addition, the Internal Revenue Service released regulations that were retroactive to January 1, 2018 and favorably impacted our calculation of adjusted taxable income. After application of these new regulations, the limitation of our interest expense deduction was significantly reduced when compared to the same calculations under the previous regulations. In the year ended December 31, 2020, we recorded a tax benefit of $13.3 million to reverse the previously-recorded valuation allowance as we are certain that we will utilize the remaining amount that was disallowed and carried forward.

In the year ended December 31, 2019, we recognized a one-time deferred tax benefit of $14.9 million upon the completion of a Dutch legal entity restructuring project. This restructuring resulted in an intra-entity transfer of certain intangible assets and intellectual property, which under Dutch tax law are valued at fair value and are amortized over a period of nine to 14 years.

Taxes Excluded from Net Income Attributable to Koppers

The amount of deferred income tax expense (benefit) included in comprehensive income (loss) but excluded from net income attributable to Koppers relating primarily to adjustments to copper swap contracts is $12.6 million, $4.1 million, and $(10.0) million for the years ended December 31, 2020, 2019 and 2018, respectively.

The amount of deferred income tax expense (benefit) included in comprehensive income (loss) but excluded from net income attributable to Koppers relating to adjustments to reflect the unfunded status of employee post-retirement benefit plans is $(0.4) million, $0.7 million, and $(0.1) million for the years ended December 31, 2020, 2019 and 2018, 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 our deferred tax assets and liabilities are as follows:

	Year Ended December 31,
	2020			2019
(Dollars in millions)
Deferred tax assets:
Tax credits	$	20.0		$	22.5
Federal and state tax loss carryforwards, expiring from 2020 to 2039		18.3			17.8
Reserves, including insurance and environmental		11.7			23.3
Pension and other postretirement benefits obligations		9.7			9.4
Foreign tax loss carryforwards		7.5			5.6
Asset retirement obligations		6.8			6.5
Accrued employee compensation		6.6			8.5
Book/tax inventory accounting differences		6.2			5.1
Other		3.1			3.3
Valuation allowance		(44.6	)		(58.0	)
Total deferred tax assets		45.3			44.0
Deferred tax liabilities:
Tax over book depreciation and amortization		28.1			25.5
Gain on derivative contracts		16.3			1.4
Other		3.8			0.2
Total deferred tax liabilities		48.2			27.1
Net deferred tax (liabilities) assets	$	(2.9	)	$	16.9

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, 2020, there was approximately $602 million of such unremitted earnings. Substantially all unremitted earnings will remain indefinitely invested in our foreign subsidiaries for the foreseeable future unless we can remit any earnings as a dividend in a tax-free manner. In the event any earnings are remitted as a dividend with a tax cost due to currency gains or losses, state taxes, or foreign withholding taxes, we estimate that we will not incur significant additional taxes on those potential remittances.

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

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,
	2020		2019
State temporary differences, net operating losses and tax credits	$	19.1	$	18.1
Federal foreign tax credits		18.8		20.5
Federal temporary differences		0.0		13.3
Foreign temporary differences, net operating losses and capital losses		6.7		6.1
Total valuation allowances	$	44.6	$	58.0

The valuation allowance for Federal temporary differences, and specifically the valuation allowance on the disallowed U.S. interest deductions, was reversed in the year ended December 31, 2020. This is due to the changes to the U.S. tax law that were enacted in 2020 and discussed in prior paragraphs.

Unrecognized Tax Benefits

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

	December 31,
	2020			2019			2018
(Dollars in millions)
Balance at beginning of year	$	2.1		$	7.0		$	8.7
Additions based on tax provisions related to the current year		0.2			0.1			0.1
Additions for tax provisions of prior years		0.5			0.0			0.0
Reductions resulting from a lapse in the statute of limitations		(0.3	)		(0.3	)		(0.3	)
Reductions of tax provisions of prior years		0.0			(1.8	)		(1.5	)
Reductions resulting from audit closures		0.0			(2.9	)		0.0
Balance at end of year	$	2.5		$	2.1		$	7.0

As of December 31, 2020 and 2019, the total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate, was approximately $2.5 million and $2.0 million, respectively.

We recognize interest expense and any related penalties from unrecognized tax benefits in income tax expense. For the year ended December 31, 2018, we recognized $1.4 million in interest and penalties. As of December 31, 2020 and 2019, we had accrued interest and penalties of approximately $0.8 million and $0.8 million, respectively.

We believe that it is reasonably possible that the amount of unrecognized tax benefits will decrease in the next twelve months by approximately $1.7 million due to the expirations of certain limitations and potential audit resolutions. We do not anticipate significant increases to the amount of unrecognized tax benefits within the next twelve months.

Koppers Holdings 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, we are no longer subject to U.S. federal, U.S. state, or non-U.S. income tax examinations by tax authorities for years before 2016.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References + Details

Inventories

12 Months Ended

Dec. 31, 2020

Inventory Disclosure [Abstract]

Inventories

11. Inventories

Inventories as of December 31, 2020 and 2019 were as follows:

	December 31,
	2020		2019
(Dollars in millions)
Raw materials	$	233.7	$	232.0
Work in process		12.4		12.0
Finished goods		99.3		107.8
		345.4		351.8
Less revaluation to LIFO		49.6		63.3
Inventories, net^(a)	$	295.8	$	288.5

(a)	Net inventories excludes $10.6 million of assets of discontinued operations held for sale related to our KJCC business as of December 31, 2019.

Property, Plant and Equipment

12 Months Ended

Dec. 31, 2020

Property Plant And Equipment [Abstract]

Property, Plant and Equipment

12. Property, Plant and Equipment

Property, plant and equipment as of December 31, 2020 and 2019 were as follows:

	December 31,
	2020		2019
(Dollars in millions)
Land	$	16.7	$	15.0
Buildings		75.0		70.5
Machinery and equipment		812.1		732.4
		903.8	$	817.9
Less accumulated depreciation		494.7		459.1
Property, Plant and Equipment, net^(a)	$	409.1	$	358.8

(a)	Net property, plant, and equipment excludes $56.6 million of assets of discontinued operations held for sale related to our KJCC business as of December 31, 2019.

Depreciation expense for the years ended December 31, 2020, 2019 and 2018 amounted to $33.7 million, $30.7 million and $27.7 million, respectively. Depreciation expense excludes KJCC discontinued operations of $0.6 million, $3.7 million and $3.9 million for the years ended December 31, 2020, 2019 and 2018, respectively

Impairments – We did not incur impairment charges in 2020, 2019 or 2018.

Goodwill and Other Identifiable Intangible Assets

12 Months Ended

Dec. 31, 2020

Goodwill And Intangible Assets Disclosure [Abstract]

Goodwill and Other Identifiable Intangible Assets

13. Goodwill and Other Identifiable Intangible Assets

The change in the carrying amount of goodwill attributable to each reporting unit for the years ended December 31, 2020 and December 31, 2019 was as follows:

	Performance Chemicals		Railroad Products and Services		Utility Products			Total
(Dollars in millions)
Balance at December 31, 2018	$	175.4	$	41.0	$	80.1		$	296.5
Purchase accounting adjustment		0.0		0.0		(0.4	)		(0.4	)
Balance at December 31, 2019	$	175.4	$	41.0	$	79.7		$	296.1
Currency translation	$	1.3	$	0.1	$	0.3		$	1.7
Balance at December 31, 2020	$	176.7	$	41.1	$	80.0		$	297.8

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 or more frequently if a change in circumstances or the occurrence of events indicates that potential impairment exists, using discounted cash flows. We performed a quantitative assessment of goodwill at the reporting unit level, utilizing a combination of an income approach, using a discounted cash flow methodology, and a market approach, by comparing the estimated fair value calculations of each reporting unit with its net book value. The discounted cash flow calculations are dependent on several subjective factors including the timing of future forecasted cash flows, including forecasted future growth rates such as revenue and the discount rate. We determined that the estimated fair values exceeded the carrying values of all the reporting units, and accordingly, there was no impairment of goodwill incurred for each of the three years ended December 31, 2020.

Our identifiable intangible assets are being amortized over their estimated useful lives and are summarized below:

					December 31,
					2020						2019
	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			9.5	$	228.5	$	84.7	$	143.8	$	227.0	$	69.5	$	157.5
Technology	4 to 12			1.9		26.8		23.6		3.2		26.7		19.9		6.8
Trademarks	2 to 17			5.1		7.9		5.8		2.1		7.6		4.4		3.2
Supply contracts		10		0.0		2.6		2.6		0.0		2.4		2.3		0.1
Non-compete agreements		12		3.8		1.7		1.0		0.7		1.6		0.8		0.8
Favorable lease agreements		3		0.0		0.8		0.8		0.0		0.7		0.7		0.0
Total				9.1	$	268.3	$	118.5	$	149.8	$	266.0	$	97.6	$	168.4

In 2020, the gross carrying value of identifiable intangible assets increased by $2.3 million. Total amortization expense related to these identifiable intangible assets was $19.8 million, $20.7 million and $19.2 million for the years ended December 31, 2020, 2019 and 2018, respectively. Estimated amortization expense for the next five years is summarized below:

	Estimated annual amortization
(Dollars in millions)
2021	$	17.7
2022		15.0
2023		14.6
2024		14.3
2025		13.8

Pensions and Post-Retirement Benefit Plans

12 Months Ended

Dec. 31, 2020

Compensation And Retirement Disclosure [Abstract]

Pensions and Post-Retirement Benefit Plans

14. Pensions and Post-Retirement Benefit Plans

We maintain a number of defined benefit and defined contribution plans to provide retirement benefits for employees in the United States, as well as employees outside the United States 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 United States, 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. We also provide 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.

Expense related to defined contribution plans totaled $8.4 million, $8.3 million and $7.5 million for the years ended December 31, 2020, 2019 and 2018, respectively.

Net periodic pension costs for 2020, 2019 and 2018 were as follows:

	Year Ended December 31,
	Pension Benefits									Other Benefits
	2020			2019			2018			2020			2019			2018
(Dollars in millions)
Service cost	$	1.4		$	1.5		$	1.9		$	0.1		$	0.1		$	0.1
Interest cost		6.4			7.8			7.5			0.3			0.4			0.4
Expected return on plan assets		(7.9	)		(7.9	)		(8.5	)		0.0			0.0			0.0
Amortization of net loss (gain)		1.7			1.6			1.4			(0.2	)		(0.2	)		0.0
Settlements and curtailments		0.1			0.0			0.0			0.0			0.0			0.0
Net periodic benefit cost	$	1.7		$	3.0		$	2.3		$	0.2		$	0.3		$	0.5

The change in the funded status of the pension and postretirement plans as of December 31, 2020 and December 31, 2019 is as follows:

	Year Ended December 31,
	Pension Benefits						Other Benefits
	2020			2019			2020			2019
(Dollars in millions)
Change in benefit obligation:
Benefit obligation at beginning of year	$	219.8		$	201.7		$	9.2		$	9.4
Service cost		1.4			1.5			0.1			0.1
Interest cost		6.4			7.8			0.3			0.4
Actuarial losses (gains)		17.3			20.1			1.3			(0.3	)
Settlements		(2.2	)		0.0			0.0			0.0
Currency translation		2.6			1.6			0.0			0.0
Benefits paid		(12.0	)		(12.9	)		(0.4	)		(0.3	)
Benefit obligation at end of year		233.3			219.8			10.5			9.2
Change in plan assets:
Fair value of plan assets at beginning of year		191.5			169.6			0.0			0.0
Actual return on plan assets		23.6			28.6			0.0			0.0
Employer contribution		3.9			4.2			0.4			0.3
Settlements		(2.2	)		0.0			0.0			0.0
Currency translation		3.2			2.0			0.0			0.0
Benefits paid		(12.0	)		(12.9	)		(0.4	)		(0.3	)
Fair value of plan assets at end of year		208.0			191.5			0.0			0.0
Funded status of the plan	$	(25.3	)	$	(28.3	)	$	(10.5	)	$	(9.2	)

In 2020, the net actuarial loss of $17.3 million is due principally to the decrease in the discount rate used to measure the benefit obligation as of December 31, 2020 compared to the prior year. In February 2021, we entered into a pension plan buy-in transaction with respect to our defined benefit pension plan in the United Kingdom with an insurance company. After completing a regulatory process which is expected to take up to ten months, our related pension obligation will be irrevocably settled. This pension plan has a benefit obligation of $56.5 million and plan assets of $68.2 million as of December 31, 2020.

Plan Data

	Year Ended December 31,
	Pension Benefits				Other Benefits
	2020		2019		2020		2019
(Dollars in millions)
Amounts recognized in the balance sheet consist of:
Noncurrent assets	$	12.1	$	10.9	$	0.0	$	0.0
Current liabilities		1.0		1.0		0.7		0.8
Noncurrent liabilities		36.4		38.2		9.8		8.4
Pension plans with projected benefit obligations in excess of plan assets:
Benefit obligation	$	172.5	$	160.4
Fair value of plan assets		135.0		121.2
Pension plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligation	$	172.2	$	160.2
Fair value of plan assets		135.0		121.2

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, 2020 and 2019 was $232.5 million and $219.0 million, respectively.

Expected Contributions for the 2021 Fiscal Year

Our expected contributions for 2021 are estimated to be $1.0 million for pension plans and $0.7 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, are expected to be paid as follows:

	Pension Benefits		Other Benefits
(Dollars in millions)
2021	$	11.6	$	0.7
2022		11.4		0.7
2023		11.5		0.7
2024		11.6		0.6
2025		12.1		0.6
Next five years		59.8		3.0

Weighted-Average Assumptions

	December 31,
	Pension Benefits						Other Benefits
	2020			2019			2020			2019
Discount rate		2.29	%		3.05	%		2.66	%		3.43	%
Expected return on plan assets		3.67			4.30
Rate of compensation increase		3.41			3.00
Initial medical trend rate								5.40			5.70

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, we 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 our pension plans at December 31 by asset category is as follows:

	December 31,
	2020			2019
Debt securities		70	%		70	%
Equity securities		21			24
Other		9			6
		100	%		100	%

Our investment strategy for our 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. Our 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, we target an allocation of 30 percent to 40 percent growth seeking assets and 60 percent to 70 percent income generating assets on an overall basis. We utilize investment managers to assist in identifying and monitoring investments that meet these allocation criteria. With respect to the U.S defined benefit plan, we have 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. Our 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. Certain investments are valued using the net asset value (“NAV”) practical expedient and have not been categorized in the fair value hierarchy but are included to reconcile the fair value hierarchy to the total fair value of plan assets. 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, our pension plan assets at fair value, within the fair value hierarchy, as of December 31, 2020 and December 31, 2019:

	December 31, 2020
	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	$	0.0	$	8.1	$	0.0	$	8.1
International equity securities		0.0		19.3		0.0		19.3
U.S. debt securities		0.0		68.6		0.0		68.6
International debt securities		0.0		62.7		0.0		62.7
Real estate and other investments		0.0		0.6		0.0		0.6
Cash and cash equivalents		0.0		11.2		0.0		11.2
	$	0.0	$	170.5	$	0.0	$	170.5
Investments measured at NAV^(a)								37.5
Total assets at fair value							$	208.0
^(a) The fair value amounts presented in the table above are intended to permit reconciliations of the fair value hierarchy to the total plan assets.

	December 31, 2019
	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	$	0.0	$	14.1	$	0.0	$	14.1
International equity securities		0.0		22.3		0.0	22.3
U.S. debt securities		0.0		58.3		0.0	58.3
International debt securities		0.0	48.1			0.0	48.1
Real estate and other investments		0.0	0.8			4.3	5.1
Cash and cash equivalents		0.0		3.6		0.0		3.6
	$	0.0	$	147.2	$	4.3	$	151.5
Investments measured at NAV^(a)								40.0
Total assets at fair value							$	191.5
^(a) The fair value amounts presented in the table above are intended to permit reconciliations of the fair value hierarchy to the total 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, 2020:

	December 31, 2020
	Other Investments
(Dollars in millions)
Balance at beginning of year	$	4.3
Purchases, sales, issuances and settlements		(4.3	)
Balance at the end of year	$	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	$	0.0

Incentive Plan

We have 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 $17.3 million in 2020, $12.2 million in 2019 and $10.3 million in 2018.

- Definition

The entire disclosure for retirement benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (q)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (r)(1)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(iii)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (l)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (r)(2)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

+ Details

Debt

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Debt

15. Debt

Debt as of December 31, 2020 and 2019 was as follows:

					December 31,
	Weighted Average Interest Rate			Maturity	2020		2019
Term Loan		2.69	%	2024	$	12.2	$	82.5
Revolving Credit Facility		2.69	%	2024		272.0		329.4
Senior Notes due 2025		6.00	%	2025		500.0		500.0
Total debt						784.2		911.9
Less short-term debt and current maturities of long-term debt						10.1		10.2
Less unamortized debt issuance costs						8.3		10.7
Long-term debt					$	765.8	$	891.0

Credit Facility

The Company maintains a $600.0 million senior secured revolving credit facility and a $100.0 million secured term loan facility (collectively, the “Credit Facility”), as amended. The secured term loan has a quarterly amortization of $2.5 million and the interest rate on the Credit Facility is variable and is based on LIBOR.

Borrowings under the Credit Facility are secured by a first priority lien on substantially all of the assets of Koppers Inc., Koppers Holdings Inc. and their material domestic subsidiaries. The 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, 2020, we had $307.8 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, 2020, $7.7 million of commitments were utilized by outstanding letters of credit.

Senior Notes due 2025

The 2025 Notes are senior obligations of Koppers Inc., 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. We are 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.

Debt Maturities and Deferred Financing Costs

At December 31, 2020 the aggregate debt maturities for the next five years are as follows:


(Dollars in millions)
2021	$	10.1
2022		2.1
2023		0.0
2024		272.0
2025		500.0
Total debt	$	784.2

Unamortized debt issuance costs (net of accumulated amortization of $9.4 million and $6.8 million at December 31, 2020 and 2019, respectively) were $8.3 million and $10.7 million at December 31, 2020 and 2019, respectively, and are included as a deduction from the carrying amount of long-term debt.

Leases

12 Months Ended

Dec. 31, 2020

Leases [Abstract]

Leases

16. Leases

We adopted the provisions of ASU 2016-02 and ASU 2018-10 on January 1, 2019 and recognized lease obligations and associated right-of-use assets for existing non-cancelable leases. We have non-cancelable operating leases primarily associated with railcars, office and manufacturing facilities, storage tanks, ships, production equipment and vehicles. Many of our leases include both lease (e.g., fixed rent) and non-lease components (e.g., maintenance and services). For certain asset classes such as railcars, storage tanks and ships, we have separated the lease and non-lease components based on the estimated stand-alone price for each component. For the remaining asset classes, we have elected the practical expedient to account for these components as a single lease component. Upon adoption, we elected other practical expedients as well, including retaining our current classification of existing leases upon adoption and excluding leases expiring within twelve months.

Many of our leases include one or more options to renew. We evaluate renewal options at the lease commencement date and regularly thereafter to determine if we are reasonably certain to exercise the option, in which case we include the renewal period in our lease term. As most of our leases do not provide an implicit rate, we use our incremental borrowing rate based on information available to determine the present value of the lease payments.

Lease expense for operating leases is recognized on a straight-line basis over the lease term. Variable lease expense is recognized in the period in which the obligation for those payments is incurred. Operating lease costs were $31.2 million and $31.8 million and variable lease costs were $3.5 million and $3.7 million during the years ended December 31, 2020 and 2019, respectively.

The following table presents information about the amount and timing of cash flows arising from our operating leases as of December 31, 2020:

(Dollars in millions)
2021	$	28.4
2022		24.6
2023		19.2
2024		15.4
2025		12.3
Thereafter		33.5
Total lease payments	$	133.5
Less: Interest		(31.0	)
Present value of lease liabilities	$	102.5

Supplemental consolidated balance sheet information related to leases is as follows:

	December 31,
	2020			2019
(Dollars in millions)
Operating leases:
Operating lease right-of-use assets	$	102.5		$	112.3
Current operating lease liabilities	$	21.2		$	22.0
Operating lease liabilities		81.3			91.5
Total operating lease liabilities	$	102.5		$	113.5
Weighted average remaining lease term, in years		6.4			6.9
Weighted average discount rate		7.5	%		7.7	%

Derivative Financial Instruments

12 Months Ended

Dec. 31, 2020

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Derivative Financial Instruments

17. Derivative Financial Instruments

We utilize derivative instruments to manage exposures to risks that have been identified and measured and are capable of being controlled. The primary risks that we manage 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 our manufacturing processes. Generally, we will not hedge cash flow exposures for durations longer than 36 months and we have hedged certain volumes of copper through the end of 2022. We enter into foreign currency forward contracts to manage foreign currency risk associated with our receivable and payable balances in addition to foreign-denominated sales. Generally, we enter into master netting arrangements with the counterparties and offset net derivative positions with the same counterparties. Currently, our 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, we designate certain of our 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 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, 2020 and December 31, 2019, we had outstanding copper swap contracts of the following amounts:

	Units Outstanding (in Pounds)				Net Fair Value - Asset (Liability)
	December 31,				December 31,
	2020		2019		2020		2019
(Amounts in millions)
Cash flow hedges		62.3		56.5	$	58.3	$	4.5
Not designated as hedges		11.5	16.6			10.9		1.7
Total		73.8		73.1	$	69.2	$	6.2

As of December 31, 2020 and December 31, 2019, the fair value of the outstanding copper swap contracts is recorded in the balance sheet as follows:

	December 31,
	2020		2019
(Dollars in millions)
Derivative contracts	$	37.3	$	2.1
Non-current derivative contracts		31.9		4.1
Net asset on balance sheet	$	69.2	$	6.2
Accumulated other comprehensive gain, net of tax	$	44.4	$	3.2

In the next twelve months, we estimate that $23.1 million of unrealized gains, net of tax, related to commodity price hedging will be reclassified from other comprehensive income into earnings.

See the consolidated statement of comprehensive income (loss) and consolidated statement of shareholders’ equity for amounts recorded in other comprehensive income and for amounts reclassified from accumulated other comprehensive income (loss) into net income for the periods specified below. For the years ended December 31, 2020 and 2019, the following amounts were recognized in earnings related to copper swap contracts:

	Year Ended December 31,
	2020		2019
(Dollars in millions)
Gain from contracts not designated as hedges	$	9.2	$	4.1

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, 2020 and December 31, 2019, the fair value of outstanding foreign currency forward contracts is recorded in the balance sheet as follows:

	December 31,
	2020			2019
(Dollars in millions)
Derivative contracts	$	1.2		$	0.3
Accrued liabilities		(0.5	)		(0.5	)
Net asset (liability) on balance sheet	$	0.7		$	(0.2	)

As of December 31, 2020 and 2019, the net currency units outstanding were:

	December 31,
	2020		2019
(In millions)
British Pounds		GBP 2.0		GBP 3.7
New Zealand Dollars		NZD 0.0		NZD 16.0
United States Dollars		USD 7.6		USD 6.2
Euro		EUR 0.0		EUR 1.2

Common Stock and Senior Convertible Preferred Stock

12 Months Ended

Dec. 31, 2020

Equity [Abstract]

Common Stock And Senior Convertible Preferred Stock

18. 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, 2020 are as follows:

	December 31,
	2020			2019			2018
(Shares in thousands)
Senior Convertible Preferred Stock:
Balance at beginning and end of year		0			0			0
Common Stock:
Balance at beginning of year		23,321			23,029			22,384
Issued for employee stock plans		367			292			645
Balance at end of year		23,688			23,321			23,029
Treasury Stock:
Balance at beginning of year		(2,516	)		(2,480	)		(1,606	)
Shares repurchased		(74	)		(36	)		(874	)
Balance at end of year		(2,590	)		(2,516	)		(2,480	)

Commitments and Contingent Liabilities

12 Months Ended

Dec. 31, 2020

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingent Liabilities

19. Commitments and Contingent Liabilities

We 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 we fail to prevail in any of these legal matters or should several of these legal matters be resolved against us 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 64 plaintiffs in 34 cases pending as of December 31, 2020, which is unchanged from December 31, 2019. As of December 31, 2020, there were 33 cases pending in the Court of Common Pleas of Allegheny County, Pennsylvania, and one case pending in the Circuit Court of Knox County, Tennessee.

The plaintiffs in all 34 pending cases seek to recover compensatory damages. Plaintiffs in 29 of those cases also seek to recover punitive damages. The plaintiffs in the 33 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.

We have not provided a reserve for the coal tar pitch lawsuits because, at this time, we 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 our business, financial condition, cash flows and results of operations.

Environmental and Other Litigation Matters

We 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. We expect to incur substantial costs for ongoing compliance with such laws and regulations. We 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. We accrue 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 We have agreements with former owners of certain of our operating locations under which the former owners retained, assumed and/or agreed to indemnify us 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, subject to the following paragraph, and agreed to share toxic tort litigation defense arising from any sites acquired from Beazer East.

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. The indemnification period ended July 14, 2019 (the “Claim Deadline”) and Beazer East may now tender certain third-party claims described in sections (i) and (ii) above to Koppers Inc. However, to the extent the third-party claims described in sections (i) and (ii) above were tendered to Beazer East by the Claim Deadline, Beazer East will continue to be required to pay the costs arising from such claims under the Indemnity. Furthermore, the Claim Deadline 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 tendered by Koppers Inc. to Beazer East.

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 our 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 us against the liabilities referred to above, including Beazer East, have performed their obligations in all material respects. We believe that, for the last three years ended December 31, 2020, amounts paid by Beazer East as a result of its environmental remediation obligations under the Indemnity have averaged, in total, approximately $6.4 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 we are held liable for or otherwise required to pay all or part of such liabilities without reimbursement, the imposition of such liabilities on us could have a material adverse effect on our business, financial condition, cash flows and results of operations. Furthermore, we could be required to record a contingent liability on our balance sheet with respect to such matters, which could result in a negative impact to our business, financial condition, cash flows and results of operations.

Domestic Environmental Matters. In June 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 our 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. In October 2020, we signed a consent decree with the EPA and agreed to a total penalty of $1.0 million which is accrued. The consent decree was entered and became effective on February 4, 2021 and the penalty will be paid in the first quarter of 2021.

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 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. At that time, 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. These costs may increase given the remedy will not be implemented for several years. Responsibility for implementing and funding that work will be decided in the separate private allocation process which is ongoing.

Additionally, Koppers Inc. is involved in two separate matters involving natural resource damages at the Portland Harbor site. One matter involves claims by the trustees to recover damages based upon an assessment of damages to natural resources caused by the releases of hazardous substances to the Willamette River. The assessment serves 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. Koppers Inc. has been engaged in a process to resolve its natural resource damage liabilities for the assessment area. A second matter involves a lawsuit filed in January 2017 by the Yakama Nation in Oregon federal court. Yakama Nation seeks recovery for response costs and the costs of assessing injury to natural resources to waterways beyond the current assessment area. Following the most recent court rulings, the Yakama Nation case has been stayed 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.

We have 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 $3.6 million as of December 31, 2020. 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 our business, financial condition, cash flows and results of operations.

There are two plant sites related to the Performance Chemicals business and one plant site related to the Utility and Industrial Products business in the United States where we have recorded environmental remediation liabilities for soil and groundwater contamination which occurred prior to our acquisition of the businesses. As of December 31, 2020, our estimated environmental remediation liability for these acquired sites totals $4.3 million.

Foreign Environmental Matters. In October 2019, the New South Wales Environment Protection Authority (“NSW EPA”) filed a proceeding against one of our Australian subsidiaries, Koppers Carbon Materials & Chemicals Pty. Ltd. (“KCMC”), in relation to an incident which occurred at our Mayfield, Australia plant in October 2018. The NSW EPA alleged that KCMC committed an offense under Australian law by failing to maintain its plant and equipment in a proper and efficient working condition. A proceeding was held in November 2019 in the Land and Environment Court of New South Wales and we entered a guilty plea with respect to the allegations.

In May 2020, the NSW EPA brought additional proceedings against KCMC related to a series of May 2019 incidents involving alleged air pollution and odor complaints. The Company agreed to plead guilty to two of the charges and both the October 2019 and May 2020 proceedings were procedurally joined. In February 2021, the Land and Environment Court entered a final order and assessed a fine of $0.1 million plus legal costs incurred by the NSW EPA. We have accrued our estimated liability associated with the matters as of December 31, 2020.

There is one plant site related to the Performance Chemicals business located in Australia where we have recorded an environmental remediation liability for soil and groundwater contamination which occurred prior to the acquisition of the business. As of December 31, 2020, our estimated environmental remediation liability for the acquired site totals $1.5 million.

Environmental Reserves Rollforward. The following table reflects changes in the accrued liability for environmental matters, excluding fines and penalties of which $2.9 million and $2.8 million are classified as current liabilities at December 31, 2020 and December 31, 2019, respectively:

	December 31,
	2020			2019
(Dollars in millions)
Balance at beginning of year	$	9.5		$	10.1
Expense		1.8			0.5
Revision of reserves		0.0			(0.8	)
Cash expenditures		(0.4	)		(0.3	)
Currency translation		0.1			0.0
Balance at end of period	$	11.0		$	9.5

Schedule II - Valuation and Qualifying Accounts

12 Months Ended

Dec. 31, 2020

Valuation And Qualifying Accounts [Abstract]

Schedule II - Valuation and Qualifying Accounts

SCHEDULE II – VALUATION AND QUALIFYING ACCOUNTS

For the years ended December 31, 2020, 2019 and 2018


	Balance at		Increase									Balance
	Beginning		(Decrease)			Net			Currency			at End
	of Year		to Expense			Write-offs			Translation			of Year
(Dollars in millions)
2020
Allowance for doubtful accounts	$	2.6	$	0.2		$	(0.2	)	$	0.0		$	2.6
Deferred tax valuation allowance	$	58.0	$	(12.1	)	$	(1.7	)	$	0.4		$	44.6
2019
Allowance for doubtful accounts	$	2.5	$	0.6		$	(0.5	)	$	0.0		$	2.6
Deferred tax valuation allowance	$	59.9	$	3.3		$	(5.2	)	$	0.0		$	58.0
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

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Basis of Presentation

Use of Estimates

Revenue Recognition

Contract Balances

Cash, Cash Equivalents and Restricted Cash

Accounts Receivable

Inventories

Property, Plant and Equipment

Goodwill and Other Intangible Assets

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. Goodwill is not amortized and is subject to an impairment test that we conduct annually or more frequently if a change in circumstances or the occurrence of eventsindicates that potential impairment exists. We perform an assessment of goodwill at the reporting unit level, utilizing a combination of an income approach, using a discounted cash flow methodology, and a market approach, by comparing the estimated fair value calculations of each reporting unit with its net book value. The discounted cash flow calculations are dependent on several subjective factors including the timing of future forecasted cash flows including future forecasted revenue growth rates, and the discount rate. If assumptions or estimates in the fair value calculations change or if future forecasted cash flows or future forecasted growth rates vary from what was planned, this may impact the impairment analysis. We performed an impairment test for goodwill for each of the reporting units using the above quantitative testing approach. Based on the evaluations performed, we determined that the fair value of each of the reporting units exceeded its carrying amount, and therefore, we determined that goodwill was not impaired.

Identifiable intangible assets, other than goodwill, are recorded at fair value. Identifiable intangible assets are amortized on a straight-line basis over their estimated useful lives.

Deferred Income Taxes

Leases

Asset Retirement Obligations

The following table describes changes to our asset retirement obligation liabilities:

	December 31,
	2020			2019
(Dollars in millions)
Asset retirement obligation at beginning of year	$	20.7		$	27.0
Accretion expense		1.1			1.5
Revision in estimated cash flows ^(a)		4.6			4.7
Cash expenditures		(6.6	)		(12.5	)
Balance at end of period	$	19.8		$	20.7

Litigation and Contingencies

Environmental Liabilities

COVID-19 Assessment

New Accounting Pronouncements

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Summary of Asset Retirement Obligation Liabilities

The following table describes changes to our asset retirement obligation liabilities:

	December 31,
	2020			2019
(Dollars in millions)
Asset retirement obligation at beginning of year	$	20.7		$	27.0
Accretion expense		1.1			1.5
Revision in estimated cash flows ^(a)		4.6			4.7
Cash expenditures		(6.6	)		(12.5	)
Balance at end of period	$	19.8		$	20.7

Plant Closures and Discontinued Operations (Tables)

12 Months Ended

Dec. 31, 2020

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			Asset retirement			Other			Total
(Dollars in millions)
Reserve at December 31, 2018	$	1.7		$	3.6		$	2.8		$	8.1
Accrual		0.0			3.4			3.0			6.4
Costs charged against assets		0.0			0.0			(3.0	)		(3.0	)
Reversal of accrued charges		(0.3	)		(0.1	)		0.0			(0.4	)
Cash paid		(0.5	)		(6.2	)		(0.3	)		(7.0	)
Currency translation		0.0			0.0			(0.1	)		(0.1	)
Reserve at December 31, 2019	$	0.9		$	0.7		$	2.4		$	4.0
Accrual		0.5			2.9			3.4			6.8
Costs charged against assets		0.0			0.0			(3.4	)		(3.4	)
Reversal of accrued charges		(0.3	)		0.0			0.0			(0.3	)
Cash paid		(0.2	)		(0.8	)		(0.3	)		(1.3	)
Currency translation		0.0			0.0			0.2			0.2
Reserve at December 31, 2020	$	0.9		$	2.8		$	2.3		$	6.0

Schedule of Net Sales and Operating (Loss) Profit from Discontinued Operations

Net sales and operating (loss) profit from discontinued operations for the years ended December 31, 2020, 2019 and 2018 consist of the following amounts:

	Year Ended December 31,
	2020			2019		2018
(Dollars in millions)
Net sales	$	31.6		$	135.8	$	147.5
Operating (loss) profit		(5.0	)		5.8		26.0

Schedule of Net cash Inflows and Outflows From Discontinued Operations

	Year Ended December 31,
	2020			2019			2018
(Dollars in millions)
Net cash provided by operating activities	$	0.7		$	21.4		$	10.4
Net cash used in investing activities		(0.9	)		(3.8	)		(3.3	)
Net cash used in financing activities		0.0			(19.8	)		(12.6	)
Effect of exchange rate changes on cash		(0.5	)		(0.3	)		(0.7	)
Net decrease in cash and cash equivalents		(0.7	)		(2.5	)		(6.2	)

Schedule of Carrying Amount of Assets and Liabilities by Major Class Classified as Held for Sale

The following represents the carrying amount of assets and liabilities, by major class, classified as held for sale on the Consolidated Balance Sheet as of December 31, 2019:

	December 31, 2019
(Dollars in millions)
Assets
Cash and cash equivalents	$	0.7
Accounts receivable		2.2
Income tax receivable		0.8
Inventories, net		10.6
Other current assets		2.8
Total current assets held for sale		17.1
Property, plant and equipment, net		56.6
Operating lease right-of-use assets		1.2
Other assets		1.5
Total non-current assets held for sale		59.3
Total assets held for sale	$	76.4
Liabilities
Accounts payable	$	7.1
Accrued liabilities		4.7
Current operating lease liabilities		0.1
Total current liabilities held for sale		11.9
Deferred tax liabilities		0.6
Operating lease liabilities		1.1
Other long-term liabilities		23.4
Total non-current liabilities held for sale		25.1
Total liabilities held for sale	$	37.0

Acquisitions (Tables)

12 Months Ended

Dec. 31, 2020

Business Combinations [Abstract]

Summary of Revenue and Income from Continuing Operations

	Year Ended December 31,
	2018
(Dollars in millions)
Pro forma revenue	$	1,613.4
Pro forma income from continuing operations attributable to Koppers		5.7
Pro forma income per share - continuing operations:
Basic -	$	0.27
Diluted -	$	0.27

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Schedule of Company's Financial Instruments

Carrying amounts and the related estimated fair values of our financial instruments as of December 31, 2020 and 2019 are as follows:

	December 31, 2020				December 31, 2019
	Fair Value		Carrying Value		Fair Value		Carrying Value
(Dollars in millions)
Financial assets:
Investments and other assets	$	1.2	$	1.2	$	1.2	$	1.2
Financial liabilities:
Long-term debt (including current portion)	$	799.2	$	784.2	$	906.9	$	911.9

Earnings per Common Share (Tables)

12 Months Ended

Dec. 31, 2020

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,
	2020			2019		2018
(Dollars in millions, except share amounts, in thousands, and per share amounts)
Net income attributable to Koppers	$	122.0		$	66.6	$	23.4
Less: (Loss) income from discontinued operations		(3.9	)		3.7		23.7
Gain on sale of discontinued operations		35.8			0.0		0.0
Plus: Non-controlling (loss) income		(1.0	)		0.8		5.8
Income from continuing operations attributable to Koppers	$	89.1		$	63.7	$	5.5
Weighted average common shares outstanding:
Basic		20,992			20,665		20,871
Effect of dilutive securities		382			403		455
Diluted		21,374			21,068		21,326
Earnings per common share – continuing operations:
Basic earnings per common share	$	4.25		$	3.09	$	0.26
Diluted earnings per common share		4.17			3.03		0.26
Other data:
Antidilutive securities excluded from computation of diluted earnings per common share		717			764		401

Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

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

Stock Options And Performance Award Fair Value Assumptions

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

	March 2020 Grant			March 2019 Grant			March 2018 Grant			March 2017 Grant
Grant date price per share of stock option award	$	19.63		$	26.63		$	41.60		$	44.10
Expected dividend yield per share		0.00	%		0.00	%		0.00	%		0.00	%
Expected life in years		6.40			6.14			5.73			5.77
Expected volatility		42.85	%		39.44	%		37.05	%		39.70	%
Risk-free interest rate		0.87	%		2.53	%		2.67	%		2.13	%
Grant date fair value per share of option awards	$	8.42		$	11.29		$	16.38		$	17.90

Summary of Performance Stock Units

The following table shows a summary of the performance stock units as of December 31, 2020:

Performance Period	Minimum Shares		Target Shares		Maximum Shares
2018 – 2020		0		3,048		6,096
2019 – 2021		0		234,597		281,536
2020 – 2022		0		154,099		308,198

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, 2020:

	Restricted Stock Units			Performance Stock Units			Total Stock Units			Weighted Average Grant Date Fair Value per Unit
Non-vested at January 1, 2020		343,012			445,186			788,198		$	40.18
Granted		369,161			232,481			601,642		$	15.86
Performance share adjustment		0			(150,464	)		(150,464	)	$	30.68
Vested		(168,534	)		(110,168	)		(278,702	)	$	41.68
Forfeited		(34,130	)		(25,291	)		(59,421	)	$	33.86
Non-vested at December 31, 2020		509,509			391,744			901,253		$	25.48

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, 2020:

	Options			Weighted Average Exercise Price per Option		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in millions)
Outstanding at December 31, 2019		966,849		$	28.45
Granted		187,701		$	19.63
Exercised		(2,500	)	$	20.00
Expired		(5,129	)	$	31.28
Forfeited		(26,667	)	$	32.45
Outstanding at December 31, 2020		1,120,254		$	26.89		5.41	$	8.6
Exercisable at December 31, 2020		776,125		$	27.39		4.05	$	6.0

Schedule of Stock-based Compensation Expense Recognized

Stock Compensation Expense

Total stock-based compensation expense recognized under our LTIP and employee stock purchase plan for the three years ended December 31, 2020 are as follows:

	Year Ended December 31,
	2020		2019		2018
(Dollars in millions)
Stock-based compensation expense recognized:
Selling, general and administrative expenses	$	11.3	$	12.1	$	12.5
Less related income tax benefit		2.2		0.2		3.1
Decrease in net income attributable to Koppers	$	9.1	$	11.9	$	9.4
Intrinsic value of exercised stock options	$	0.0	$	1.1	$	1.1
Cash received from the exercise of stock options	$	0.0	$	2.9	$	2.9

Performance Stock Units [Member]

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

Stock Options And Performance Award Fair Value Assumptions

We calculated the fair value of the performance stock unit awards on the date of the grant using assumptions listed below:

	March 2020 Grant			March 2019 Grant			May 2018 Grant			March 2018 Grant
Grant date price per share of performance award	$	19.63		$	26.63		$	39.10		$	41.60
Expected dividend yield per share		0.00	%		0.00	%		0.00	%		0.00	%
Expected volatility		45.60	%		39.00	%		39.40	%		39.40	%
Risk-free interest rate		0.72	%		2.50	%		2.35	%		2.38	%
Look-back period in years		2.83			2.82			2.84			2.84
Grant date fair value per share of performance award	$	11.56		$	40.30		$	44.29		$	47.12

Segment Information (Tables)

12 Months Ended

Dec. 31, 2020

Segment Reporting [Abstract]

Summary of Results of Segment Operations

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

	Year Ended December 31,
	2020			2019			2018
(Dollars in millions)
Revenues from external customers:
Railroad and Utility Products and Services	$	759.1		$	733.5		$	634.8
Performance Chemicals		526.3			448.3			420.0
Carbon Materials and Chemicals^(a)		383.7			455.2			507.9
Total	$	1,669.1		$	1,637.0		$	1,562.7
Intersegment revenues:
Performance Chemicals	$	13.7		$	12.6		$	10.8
Carbon Materials and Chemicals		78.7			75.2			77.3
Total	$	92.4		$	87.8		$	88.1
Depreciation and amortization expense:
Railroad and Utility Products and Services	$	20.1		$	19.4		$	17.7
Performance Chemicals		18.1			18.3			17.8
Carbon Materials and Chemicals^(b)		15.9			13.7			11.4
Total	$	54.1		$	51.4		$	46.9
Operating profit (loss):
Railroad and Utility Products and Services^(c)	$	46.7		$	35.8		$	5.9
Performance Chemicals		88.6			52.1			36.2
Carbon Materials and Chemicals^(d)		23.4			39.2			44.7
Corporate^(e)		(2.0	)		(2.1	)		(2.4	)
Total	$	156.7		$	125.0		$	84.4
Capital expenditures (excluding acquisitions):
Railroad and Utility Products and Services	$	31.3		$	11.6		$	19.2
Performance Chemicals		12.1			9.7			15.1
Carbon Materials and Chemicals^(f)		24.8			15.5			73.5
Corporate		1.6			0.4			1.9
Total	$	69.8		$	37.2		$	109.7

(a)	Revenue excludes KJCC discontinued operations of $31.6 million, $135.8 million and $147.5 million for the years ended December 31, 2020, 2019 and 2018, respectively.

(b)	Depreciation and amortization expense excludes KJCC discontinued operations of $0.6 million, $3.7 million and $3.9 million for the years ended December 31, 2020, 2019 and 2018, respectively.

(c)	Includes $6.0 million of inventory fair value purchase price accounting adjustments from our acquisition of UIP in 2018.

(d)	Operating profit (loss) excludes KJCC discontinued operations of $(5.0) million, $5.8 million and $26.0 million for the years ended December 31, 2020, 2019 and 2018, respectively.

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

(f)	Capital expenditures includes KJCC discontinued operations of $0.6 million, $3.9 million and $3.4 million for the years ended December 31, 2020, 2019 and 2018, respectively.

Summary of Tangible and Intangible Assets by Segments

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

	December 31,
	2020		2019
(Dollars in millions)
Segment assets:
Railroad and Utility Products and Services	$	583.1	$	562.2
Performance Chemicals		536.1		457.7
Carbon Materials and Chemicals		424.2		502.1
Segment assets		1,543.4		1,522.0
Cash and cash equivalents		0.4		0.0
Income tax receivable		1.2		1.9
Deferred taxes		28.8		17.0
Property, plant and equipment, net		5.9		5.3
Operating lease right-of-use assets		11.9		13.2
Prepaid insurance and other assets		7.0		5.2
Total^(a)	$	1,598.6	$	1,564.6
Goodwill:
Railroad and Utility Products and Services	$	121.1	$	120.7
Performance Chemicals		176.7		175.4
Total	$	297.8	$	296.1

(a)	The Carbon Materials and Chemicals segment includes $76.4 million of assets of discontinued operations held for sale related to our KJCC business at December 31, 2019.

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		2020	$	1,170.1	$	832.0
		2019		1,141.2		796.0
		2018		993.5		732.1
Australasia		2020		194.3		82.0
		2019		199.6		76.6
		2018		218.8		69.8
Europe		2020		162.3		83.2
		2019		177.5		70.2
		2018		214.6		44.8
Other countries		2020		142.4		18.5
		2019		118.7		19.3
		2018		135.8		18.3
Total^(a)		2020	$	1,669.1	$	1,015.7
		2019	$	1,637.0	$	962.1
		2018	$	1,562.7	$	865.1

(a)

Schedule of Segment Revenues for Significant Product Lines

Segment Revenues for Significant Product Lines

	Year Ended December 31,
	2020		2019		2018
(Dollars in millions)
Railroad and Utility Products and Services:
Railroad treated products	$	405.1	$	419.6	$	341.7
Utility poles		241.7		222.0		184.7
Railroad infrastructure services		63.5		36.5		36.9
Rail joints		20.3		26.8		33.5
Other products		28.6		28.6		38.0
		759.1		733.5		634.8
Performance Chemicals:
Wood preservative products		510.7		418.8		389.1
Other products		15.6		29.5		30.9
		526.3		448.3		420.0
Carbon Materials and Chemicals:
Pitch and related products		230.9		272.4		280.9
Phthalic anhydride and other chemicals		66.4		77.9		84.6
Creosote and distillates		40.0		46.3		84.1
Naphthalene		19.7		24.9		26.2
Other products		26.7		33.7		32.1
		383.7		455.2		507.9
Total^(a)	$	1,669.1	$	1,637.0	$	1,562.7

(a)	Revenue excludes KJCC discontinued operations of $31.6 million, $135.8 million and $147.5 million for the years ended December 31, 2020, 2019 and 2018, respectively.

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Summary of Income Tax Provision

Components of our income tax provision are as follows:

	Year Ended December 31,
	2020		2019			2018
(Dollars in millions)
Current:
Federal	$	0.8	$	(3.5	)	$	(1.2	)
State		0.7		0.5			0.1
Foreign		11.1		14.4			17.9
Total current tax provision		12.6		11.4			16.8
Deferred:
Federal		6.1		3.1			9.6
State		1.6		0.4			(0.2	)
Foreign		0.7		(14.9	)		(0.5	)
Total deferred tax provision (benefit)		8.4		(11.4	)		8.9
Total income tax provision	$	21.0	$	0.0		$	25.7

Summary of Income Taxes Reconciled with Federal Statutory Rate

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

	Year Ended December 31,
	2020			2019			2018
Federal income tax rate		21.0	%		21.0	%		21.0	%
GILTI inclusion, net of foreign tax credits		4.0			1.4			21.1
Foreign earnings taxed at different rates		2.9			(0.2	)		0.4
State income taxes, net of federal tax benefit		2.2			1.1			(5.9	)
Transition tax from Tax Act		0.0			0.0			27.3
Deferred tax adjustments from Tax Act		0.0			0.0			(12.0	)
Intra-entity transfer of intangible assets		0.0			(23.4	)		0.0
Change in tax contingency reserves		(0.2	)		(7.0	)		(3.5	)
Deferred tax adjustments		(2.2	)		0.0			4.0
Valuation allowance adjustments		(12.1	)		9.1			28.8
Other		3.5			(2.0	)		1.2
		19.1	%		0.0	%		82.4	%

Summary of Deferred Tax Assets and Liabilities

Significant components of our deferred tax assets and liabilities are as follows:

	Year Ended December 31,
	2020			2019
(Dollars in millions)
Deferred tax assets:
Tax credits	$	20.0		$	22.5
Federal and state tax loss carryforwards, expiring from 2020 to 2039		18.3			17.8
Reserves, including insurance and environmental		11.7			23.3
Pension and other postretirement benefits obligations		9.7			9.4
Foreign tax loss carryforwards		7.5			5.6
Asset retirement obligations		6.8			6.5
Accrued employee compensation		6.6			8.5
Book/tax inventory accounting differences		6.2			5.1
Other		3.1			3.3
Valuation allowance		(44.6	)		(58.0	)
Total deferred tax assets		45.3			44.0
Deferred tax liabilities:
Tax over book depreciation and amortization		28.1			25.5
Gain on derivative contracts		16.3			1.4
Other		3.8			0.2
Total deferred tax liabilities		48.2			27.1
Net deferred tax (liabilities) assets	$	(2.9	)	$	16.9

Summary of Valuation Allowances Recorded to Offset Deferred Tax Assets

Valuation allowances are recorded to offset the following deferred tax assets:

	December 31,
	2020		2019
State temporary differences, net operating losses and tax credits	$	19.1	$	18.1
Federal foreign tax credits		18.8		20.5
Federal temporary differences		0.0		13.3
Foreign temporary differences, net operating losses and capital losses		6.7		6.1
Total valuation allowances	$	44.6	$	58.0

Summary of Unrecognized Tax Benefits

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

	December 31,
	2020			2019			2018
(Dollars in millions)
Balance at beginning of year	$	2.1		$	7.0		$	8.7
Additions based on tax provisions related to the current year		0.2			0.1			0.1
Additions for tax provisions of prior years		0.5			0.0			0.0
Reductions resulting from a lapse in the statute of limitations		(0.3	)		(0.3	)		(0.3	)
Reductions of tax provisions of prior years		0.0			(1.8	)		(1.5	)
Reductions resulting from audit closures		0.0			(2.9	)		0.0
Balance at end of year	$	2.5		$	2.1		$	7.0

Inventories (Tables)

12 Months Ended

Dec. 31, 2020

Inventory Disclosure [Abstract]

Components of Inventories

Inventories as of December 31, 2020 and 2019 were as follows:

	December 31,
	2020		2019
(Dollars in millions)
Raw materials	$	233.7	$	232.0
Work in process		12.4		12.0
Finished goods		99.3		107.8
		345.4		351.8
Less revaluation to LIFO		49.6		63.3
Inventories, net^(a)	$	295.8	$	288.5

(a)	Net inventories excludes $10.6 million of assets of discontinued operations held for sale related to our KJCC business as of December 31, 2019.

Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2020

Property Plant And Equipment [Abstract]

Property, Plant and Equipment

Property, plant and equipment as of December 31, 2020 and 2019 were as follows:

	December 31,
	2020		2019
(Dollars in millions)
Land	$	16.7	$	15.0
Buildings		75.0		70.5
Machinery and equipment		812.1		732.4
		903.8	$	817.9
Less accumulated depreciation		494.7		459.1
Property, Plant and Equipment, net^(a)	$	409.1	$	358.8

(a)	Net property, plant, and equipment excludes $56.6 million of assets of discontinued operations held for sale related to our KJCC business as of December 31, 2019.

Goodwill and Other Identifiable Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2020

Goodwill And Intangible Assets Disclosure [Abstract]

Changes in Carrying Amount of Goodwill

The change in the carrying amount of goodwill attributable to each reporting unit for the years ended December 31, 2020 and December 31, 2019 was as follows:

	Performance Chemicals		Railroad Products and Services		Utility Products			Total
(Dollars in millions)
Balance at December 31, 2018	$	175.4	$	41.0	$	80.1		$	296.5
Purchase accounting adjustment		0.0		0.0		(0.4	)		(0.4	)
Balance at December 31, 2019	$	175.4	$	41.0	$	79.7		$	296.1
Currency translation	$	1.3	$	0.1	$	0.3		$	1.7
Balance at December 31, 2020	$	176.7	$	41.1	$	80.0		$	297.8

Schedule of Identifiable Intangible Assets

Our identifiable intangible assets are being amortized over their estimated useful lives and are summarized below:

					December 31,
					2020						2019
	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			9.5	$	228.5	$	84.7	$	143.8	$	227.0	$	69.5	$	157.5
Technology	4 to 12			1.9		26.8		23.6		3.2		26.7		19.9		6.8
Trademarks	2 to 17			5.1		7.9		5.8		2.1		7.6		4.4		3.2
Supply contracts		10		0.0		2.6		2.6		0.0		2.4		2.3		0.1
Non-compete agreements		12		3.8		1.7		1.0		0.7		1.6		0.8		0.8
Favorable lease agreements		3		0.0		0.8		0.8		0.0		0.7		0.7		0.0
Total				9.1	$	268.3	$	118.5	$	149.8	$	266.0	$	97.6	$	168.4

Schedule of Future Amortization Expense

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

	Estimated annual amortization
(Dollars in millions)
2021	$	17.7
2022		15.0
2023		14.6
2024		14.3
2025		13.8

Pensions and Post-Retirement Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2020

Compensation And Retirement Disclosure [Abstract]

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

Net periodic pension costs for 2020, 2019 and 2018 were as follows:

	Year Ended December 31,
	Pension Benefits									Other Benefits
	2020			2019			2018			2020			2019			2018
(Dollars in millions)
Service cost	$	1.4		$	1.5		$	1.9		$	0.1		$	0.1		$	0.1
Interest cost		6.4			7.8			7.5			0.3			0.4			0.4
Expected return on plan assets		(7.9	)		(7.9	)		(8.5	)		0.0			0.0			0.0
Amortization of net loss (gain)		1.7			1.6			1.4			(0.2	)		(0.2	)		0.0
Settlements and curtailments		0.1			0.0			0.0			0.0			0.0			0.0
Net periodic benefit cost	$	1.7		$	3.0		$	2.3		$	0.2		$	0.3		$	0.5

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, 2020 and December 31, 2019 is as follows:

	Year Ended December 31,
	Pension Benefits						Other Benefits
	2020			2019			2020			2019
(Dollars in millions)
Change in benefit obligation:
Benefit obligation at beginning of year	$	219.8		$	201.7		$	9.2		$	9.4
Service cost		1.4			1.5			0.1			0.1
Interest cost		6.4			7.8			0.3			0.4
Actuarial losses (gains)		17.3			20.1			1.3			(0.3	)
Settlements		(2.2	)		0.0			0.0			0.0
Currency translation		2.6			1.6			0.0			0.0
Benefits paid		(12.0	)		(12.9	)		(0.4	)		(0.3	)
Benefit obligation at end of year		233.3			219.8			10.5			9.2
Change in plan assets:
Fair value of plan assets at beginning of year		191.5			169.6			0.0			0.0
Actual return on plan assets		23.6			28.6			0.0			0.0
Employer contribution		3.9			4.2			0.4			0.3
Settlements		(2.2	)		0.0			0.0			0.0
Currency translation		3.2			2.0			0.0			0.0
Benefits paid		(12.0	)		(12.9	)		(0.4	)		(0.3	)
Fair value of plan assets at end of year		208.0			191.5			0.0			0.0
Funded status of the plan	$	(25.3	)	$	(28.3	)	$	(10.5	)	$	(9.2	)

Plan Data

	Year Ended December 31,
	Pension Benefits				Other Benefits
	2020		2019		2020		2019
(Dollars in millions)
Amounts recognized in the balance sheet consist of:
Noncurrent assets	$	12.1	$	10.9	$	0.0	$	0.0
Current liabilities		1.0		1.0		0.7		0.8
Noncurrent liabilities		36.4		38.2		9.8		8.4
Pension plans with projected benefit obligations in excess of plan assets:
Benefit obligation	$	172.5	$	160.4
Fair value of plan assets		135.0		121.2
Pension plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligation	$	172.2	$	160.2
Fair value of plan assets		135.0		121.2

Schedule of 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, are expected to be paid as follows:

	Pension Benefits		Other Benefits
(Dollars in millions)
2021	$	11.6	$	0.7
2022		11.4		0.7
2023		11.5		0.7
2024		11.6		0.6
2025		12.1		0.6
Next five years		59.8		3.0

Schedule of Weighted-Average Assumptions

Weighted-Average Assumptions

	December 31,
	Pension Benefits						Other Benefits
	2020			2019			2020			2019
Discount rate		2.29	%		3.05	%		2.66	%		3.43	%
Expected return on plan assets		3.67			4.30
Rate of compensation increase		3.41			3.00
Initial medical trend rate								5.40			5.70

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

The weighted average asset allocation for our pension plans at December 31 by asset category is as follows:

	December 31,
	2020			2019
Debt securities		70	%		70	%
Equity securities		21			24
Other		9			6
		100	%		100	%

Schedule of Pension Plan Assets at Fair Value

The following table sets forth by level, our pension plan assets at fair value, within the fair value hierarchy, as of December 31, 2020 and December 31, 2019:

	December 31, 2020
	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	$	0.0	$	8.1	$	0.0	$	8.1
International equity securities		0.0		19.3		0.0		19.3
U.S. debt securities		0.0		68.6		0.0		68.6
International debt securities		0.0		62.7		0.0		62.7
Real estate and other investments		0.0		0.6		0.0		0.6
Cash and cash equivalents		0.0		11.2		0.0		11.2
	$	0.0	$	170.5	$	0.0	$	170.5
Investments measured at NAV^(a)								37.5
Total assets at fair value							$	208.0
^(a) The fair value amounts presented in the table above are intended to permit reconciliations of the fair value hierarchy to the total plan assets.

	December 31, 2019
	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	$	0.0	$	14.1	$	0.0	$	14.1
International equity securities		0.0		22.3		0.0	22.3
U.S. debt securities		0.0		58.3		0.0	58.3
International debt securities		0.0	48.1			0.0	48.1
Real estate and other investments		0.0	0.8			4.3	5.1
Cash and cash equivalents		0.0		3.6		0.0		3.6
	$	0.0	$	147.2	$	4.3	$	151.5
Investments measured at NAV^(a)								40.0
Total assets at fair value							$	191.5
^(a) The fair value amounts presented in the table above are intended to permit reconciliations of the fair value hierarchy to the total plan assets.

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, 2020:

	December 31, 2020
	Other Investments
(Dollars in millions)
Balance at beginning of year	$	4.3
Purchases, sales, issuances and settlements		(4.3	)
Balance at the end of year	$	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	$	0.0

Debt (Tables)

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Schedule of Long-Term Debt Instruments

Debt as of December 31, 2020 and 2019 was as follows:

					December 31,
	Weighted Average Interest Rate			Maturity	2020		2019
Term Loan		2.69	%	2024	$	12.2	$	82.5
Revolving Credit Facility		2.69	%	2024		272.0		329.4
Senior Notes due 2025		6.00	%	2025		500.0		500.0
Total debt						784.2		911.9
Less short-term debt and current maturities of long-term debt						10.1		10.2
Less unamortized debt issuance costs						8.3		10.7
Long-term debt					$	765.8	$	891.0

Schedule of Debt Maturities

At December 31, 2020 the aggregate debt maturities for the next five years are as follows:


(Dollars in millions)
2021	$	10.1
2022		2.1
2023		0.0
2024		272.0
2025		500.0
Total debt	$	784.2

- 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.

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+ Details

Leases (Tables)

12 Months Ended

Dec. 31, 2020

Leases [Abstract]

Summary of Amount and Timing of Cash Flows From Operating Leases

The following table presents information about the amount and timing of cash flows arising from our operating leases as of December 31, 2020:

(Dollars in millions)
2021	$	28.4
2022		24.6
2023		19.2
2024		15.4
2025		12.3
Thereafter		33.5
Total lease payments	$	133.5
Less: Interest		(31.0	)
Present value of lease liabilities	$	102.5

Schedule of Supplemental Consolidated Balance Sheet Information Related to Leases

Supplemental consolidated balance sheet information related to leases is as follows:

	December 31,
	2020			2019
(Dollars in millions)
Operating leases:
Operating lease right-of-use assets	$	102.5		$	112.3
Current operating lease liabilities	$	21.2		$	22.0
Operating lease liabilities		81.3			91.5
Total operating lease liabilities	$	102.5		$	113.5
Weighted average remaining lease term, in years		6.4			6.9
Weighted average discount rate		7.5	%		7.7	%

Derivative Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2020

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Schedule of Outstanding Copper Swap Contracts

As of December 31, 2020 and December 31, 2019, we had outstanding copper swap contracts of the following amounts:

	Units Outstanding (in Pounds)				Net Fair Value - Asset (Liability)
	December 31,				December 31,
	2020		2019		2020		2019
(Amounts in millions)
Cash flow hedges		62.3		56.5	$	58.3	$	4.5
Not designated as hedges		11.5	16.6			10.9		1.7
Total		73.8		73.1	$	69.2	$	6.2

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

As of December 31, 2020 and December 31, 2019, the fair value of the outstanding copper swap contracts is recorded in the balance sheet as follows:

	December 31,
	2020		2019
(Dollars in millions)
Derivative contracts	$	37.3	$	2.1
Non-current derivative contracts		31.9		4.1
Net asset on balance sheet	$	69.2	$	6.2
Accumulated other comprehensive gain, net of tax	$	44.4	$	3.2

Summary of Amount Recognized in Earnings Related to Copper Swap Contracts

	Year Ended December 31,
	2020		2019
(Dollars in millions)
Gain from contracts not designated as hedges	$	9.2	$	4.1

Schedule of Fair Value of Outstanding Foreign Currency Forward Contracts

As of December 31, 2020 and December 31, 2019, the fair value of outstanding foreign currency forward contracts is recorded in the balance sheet as follows:

	December 31,
	2020			2019
(Dollars in millions)
Derivative contracts	$	1.2		$	0.3
Accrued liabilities		(0.5	)		(0.5	)
Net asset (liability) on balance sheet	$	0.7		$	(0.2	)

Summary of Net Currency Units Outstanding

As of December 31, 2020 and 2019, the net currency units outstanding were:

	December 31,
	2020		2019
(In millions)
British Pounds		GBP 2.0		GBP 3.7
New Zealand Dollars		NZD 0.0		NZD 16.0
United States Dollars		USD 7.6		USD 6.2
Euro		EUR 0.0		EUR 1.2

Common Stock and Senior Convertible Preferred Stock (Tables)

12 Months Ended

Dec. 31, 2020

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, 2020 are as follows:

	December 31,
	2020			2019			2018
(Shares in thousands)
Senior Convertible Preferred Stock:
Balance at beginning and end of year		0			0			0
Common Stock:
Balance at beginning of year		23,321			23,029			22,384
Issued for employee stock plans		367			292			645
Balance at end of year		23,688			23,321			23,029
Treasury Stock:
Balance at beginning of year		(2,516	)		(2,480	)		(1,606	)
Shares repurchased		(74	)		(36	)		(874	)
Balance at end of year		(2,590	)		(2,516	)		(2,480	)

- 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.

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+ Details

Commitments and Contingent Liabilities (Tables)

12 Months Ended

Dec. 31, 2020

Commitments And Contingencies Disclosure [Abstract]

Changes in Accrued Liability for Environmental Matters

The following table reflects changes in the accrued liability for environmental matters, excluding fines and penalties of which $2.9 million and $2.8 million are classified as current liabilities at December 31, 2020 and December 31, 2019, respectively

	December 31,
	2020			2019
(Dollars in millions)
Balance at beginning of year	$	9.5		$	10.1
Expense		1.8			0.5
Revision of reserves		0.0			(0.8	)
Cash expenditures		(0.4	)		(0.3	)
Currency translation		0.1			0.0
Balance at end of period	$	11.0		$	9.5

Description of Business - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2020 Segment
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of operating segments	3

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary Of Significant Accounting Policies [Line Items]
Period for payment terms on ship and invoice arrangements.	45 days
Period for payment of approval basis sale	30 days
Contract Assets	$ 5,800,000	$ 5,100,000
Restricted cash	$ 2,300,000
Percentage of LIFO inventory	53.00%	51.00%
Inventory write-down	$ 600,000	$ 1,000,000.0	$ 1,000,000.0
Goodwill impairment charge	$ 0	$ 0	$ 0
Buildings [Member] \| Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	10 years
Buildings [Member] \| Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	20 years
Machinery and Equipment [Member] \| Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Machinery and Equipment [Member] \| Maximum [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, 2020	Dec. 31, 2019
Asset Retirement Obligation Disclosure [Abstract]
Asset retirement obligation at beginning of year	$ 20.7	$ 27.0
Accretion expense	1.1	1.5
Revision in estimated cash flows (a)	4.6	4.7
Cash expenditures	(6.6)	(12.5)
Balance at end of period	$ 19.8	$ 20.7

Summary of Significant Accounting Policies - Summary of Asset Retirement Obligation Liabilities (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Charges related to restructuring activities	$ 2.9	$ 3.4

Plant Closures and Discontinued Operations - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Nov. 30, 2016	Mar. 31, 2016	Jul. 31, 2015
Restructuring Cost And Reserve [Line Items]
Gain on sale of discontinued operations, net of tax expense of $8.3		$ 35.8	$ 0.0	$ 0.0
Restricted cash held with escrow	$ 2.3
Period of time from acquisition date for indemnity claims	15 months
Impairment charge		0.0
Aggregate disvestiture cost		$ 4.9
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%
KSA Limited Partnership [Member]
Restructuring Cost And Reserve [Line Items]
Ownership percentage							50.00%
Koppers (Jiangsu) Carbon Chemical Company Limited [Member]
Restructuring Cost And Reserve [Line Items]
Disposal group, including discontinued operation, costs of goods sold	$ 107.0
Discontinued operation, gain (loss) on disposal of discontinued operation, before income tax	44.1
Gain on sale of discontinued operations, net of tax expense of $8.3	35.8
Net cash provided by (used in) discontinued operations	$ 65.2
Koppers (Jiangsu) Carbon Chemical Company Limited [Member] \| Carbon Materials and Chemicals [Member]
Restructuring Cost And Reserve [Line Items]
Ownership percentage	75.00%

Plant Closures and Discontinued Operations - Summary of Restructuring Activities and Related Reserves (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost And Reserve [Line Items]
Reserve, Beginning Balance	$ 4.0	$ 8.1
Accrual	6.8	6.4
Costs charged against assets	(3.4)	(3.0)
Reversal of accrued charges	(0.3)	(0.4)
Cash paid	(1.3)	(7.0)
Currency translation	0.2	(0.1)
Reserve, Ending Balance	6.0	4.0
Severance and Employee Benefits [Member]
Restructuring Cost And Reserve [Line Items]
Reserve, Beginning Balance	0.9	1.7
Accrual	0.5	0.0
Costs charged against assets	(0.0)	(0.0)
Reversal of accrued charges	(0.3)	(0.3)
Cash paid	(0.2)	(0.5)
Currency translation	0.0	0.0
Reserve, Ending Balance	0.9	0.9
Asset Retirement [Member]
Restructuring Cost And Reserve [Line Items]
Reserve, Beginning Balance	0.7	3.6
Accrual	2.9	3.4
Costs charged against assets	(0.0)	(0.0)
Reversal of accrued charges	(0.0)	(0.1)
Cash paid	(0.8)	(6.2)
Currency translation	0.0	0.0
Reserve, Ending Balance	2.8	0.7
Other [Member]
Restructuring Cost And Reserve [Line Items]
Reserve, Beginning Balance	2.4	2.8
Accrual	3.4	3.0
Costs charged against assets	(3.4)	(3.0)
Reversal of accrued charges	(0.0)	(0.0)
Cash paid	(0.3)	(0.3)
Currency translation	0.2	(0.1)
Reserve, Ending Balance	$ 2.3	$ 2.4

Plant Closures and Discontinued Operations - Schedule of Net Sales and Operating Loss Profit from Discontinued Operations (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Discontinued Operations And Disposal Groups [Abstract]
Net sales	$ 31.6	$ 135.8	$ 147.5
Operating (loss) profit	$ (5.0)	$ 5.8	$ 26.0

Plant Closures and Discontinued Operations - Schedule of Net cash Inflows and Outflows From Discontinued Operations (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Discontinued Operations And Disposal Groups [Abstract]
Net cash provided by operating activities	$ 0.7	$ 21.4	$ 10.4
Net cash used in investing activities	(0.9)	(3.8)	(3.3)
Net cash used in financing activities	0.0	(19.8)	(12.6)
Effect of exchange rate changes on cash	(0.5)	(0.3)	(0.7)
Net (decrease) increase in cash and cash equivalents	$ (0.7)	$ (2.5)	$ (6.2)

Plant Closures and Discontinued Operations - Schedule of Carrying Amount of Assets and Liabilities by Major Class Classified as Held for Sale (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Assets
Cash and cash equivalents		$ 0.7
Accounts receivable		2.2
Income tax receivable		0.8
Inventories, net		10.6
Other current assets		2.8
Total current assets held for sale	$ 0.0	17.1
Property, plant and equipment, net		56.6
Operating lease right-of-use assets		1.2
Other assets		1.5
Total non-current assets held for sale	0.0	59.3
Total assets held for sale		76.4
Liabilities
Accounts payable		7.1
Accrued liabilities		4.7
Current operating lease liabilities		0.1
Total current liabilities held for sale	0.0	11.9
Deferred tax liabilities		0.6
Operating lease liabilities		1.1
Other long-term liabilities		23.4
Total non-current liabilities held for sale	$ 0.0	25.1
Total liabilities held for sale		$ 37.0

Acquisitions - Additional Information (Detail) - USD ($) $ in Millions			12 Months Ended
	Apr. 10, 2018	Feb. 28, 2018	Dec. 31, 2018
Business Acquisition [Line Items]
Combined costs related to acquisitions			$ 6.5
Koppers Utility and Industrial Products Inc. [Member]
Business Acquisition [Line Items]
Cash consideration	$ 201.3
Koppers Recovery Resources LLC [Member]
Business Acquisition [Line Items]
Cash consideration		$ 62.8

Acquisitions - Summary of Revenue and Income from Continuing Operations (Detail) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) $ / shares
Business Combinations [Abstract]
Pro forma revenue \| $	$ 1,613.4
Pro forma income from continuing operations attributable to Koppers \| $	$ 5.7
Pro forma income per share - continuing operations, Basic \| $ / shares	$ 0.27
Pro forma income per share - continuing operations, Diluted \| $ / shares	$ 0.27

Fair Value Measurements - Schedule of Company's Financial Instruments (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Fair Value [Member]
Financial assets:
Investments and other assets	$ 1.2	$ 1.2
Financial liabilities:
Long-term debt (including current portion)	799.2	906.9
Carrying Value [Member]
Financial assets:
Investments and other assets	1.2	1.2
Financial liabilities:
Long-term debt (including current portion)	$ 784.2	$ 911.9

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	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net income attributable to Koppers	$ 122.0	$ 66.6	$ 23.4
Less: (Loss) income from discontinued operations	(3.9)	3.7	23.7
Gain on sale of discontinued operations	35.8	0.0	0.0
Plus: Non-controlling (loss) income	(1.0)	0.8	5.8
Income from continuing operations attributable to Koppers	$ 89.1	$ 63.7	$ 5.5
Weighted average common shares outstanding:
Basic	20,992	20,665	20,871
Effect of dilutive securities	382	403	455
Diluted	21,374	21,068	21,326
Earnings per common share – continuing operations:
Basic earnings per common share	$ 4.25	$ 3.09	$ 0.26
Diluted earnings per common share	$ 4.17	$ 3.03	$ 0.26
Other data:
Antidilutive securities excluded from computation of diluted earnings per common share	717	764	401

Stock-based Compensation - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future compensation expense related to non-vested stock-based compensation arrangements \| $	$ 14.6
Future compensation expense, weighted-average expected period of recognition in months	26 months
Restricted Stock Units (RSUs) [Member] \| Board of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards, vesting period	1 year
Restricted Stock Units (RSUs) [Member] \| 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 performance stock units if minimum performance criteria are not achieved \| shares	0
Stock options, term in years	3 years
Performance Stock Units [Member] \| Maximum [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]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target award earned by participants	0.00%
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, 2020 $ / shares
March 2020 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of performance award	$ 19.63
Expected dividend yield per share	0.00%
Expected volatility	42.85%
Risk-free interest rate	0.87%
Grant date fair value per share of performance award	$ 8.42
March 2020 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	$ 19.63
Expected dividend yield per share	0.00%
Expected volatility	45.60%
Risk-free interest rate	0.72%
Look-back period in years	2 years 9 months 29 days
Grant date fair value per share of performance award	$ 11.56
March 2019 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of performance award	$ 26.63
Expected dividend yield per share	0.00%
Expected volatility	39.44%
Risk-free interest rate	2.53%
Grant date fair value per share of performance award	$ 11.29
March 2019 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	$ 26.63
Expected dividend yield per share	0.00%
Expected volatility	39.00%
Risk-free interest rate	2.50%
Look-back period in years	2 years 9 months 25 days
Grant date fair value per share of performance award	$ 40.30
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 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

Stock-based Compensation - Summary of Performance Stock Units (Detail) - shares	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	901,253	788,198
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	391,744	445,186
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
Minimum [Member] \| 2019 - 2021 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	0
Minimum [Member] \| 2020 - 2022 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	0
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	3,048
Target Shares [Member] \| 2019 - 2021 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	234,597
Target Shares [Member] \| 2020 - 2022 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	154,099
Maximum [Member] \| 2018 - 2020 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	6,096
Maximum [Member] \| 2019 - 2021 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	281,536
Maximum [Member] \| 2020 - 2022 [Member] \| Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	308,198

Stock-based Compensation - Summary of Status and Activity of Non-Vested Stock Awards (Detail)	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested, Beginning Balance	788,198
Granted	601,642
Performance share adjustment	(150,464)
Vested	(278,702)
Forfeited	(59,421)
Non-vested, Ending Balance	901,253
Beginning Balance, Non-vested, Weighted Average Grant Date Fair Value per Unit \| $ / shares	$ 40.18
Granted, Weighted Average Grant Date Fair Value per Unit \| $ / shares	15.86
Performance share adjustment, Weighted Average Grant Date Fair Value per Unit \| $ / shares	30.68
Vested, Weighted Average Grant Date Fair Value per Unit \| $ / shares	41.68
Forfeited, Weighted Average Grant Date Fair Value per Unit \| $ / shares	33.86
Ending Balance, Non-vested, Weighted Average Grant Date Fair Value per Unit \| $ / shares	$ 25.48
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested, Beginning Balance	343,012
Granted	369,161
Performance share adjustment	0
Vested	(168,534)
Forfeited	(34,130)
Non-vested, Ending Balance	509,509
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested, Beginning Balance	445,186
Granted	232,481
Performance share adjustment	(150,464)
Vested	(110,168)
Forfeited	(25,291)
Non-vested, Ending Balance	391,744

Stock-based Compensation - Stock Options Fair Value Assumptions (Detail)	12 Months Ended
	Dec. 31, 2020 $ / shares
March 2020 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of stock option award	$ 19.63
Expected dividend yield per share	0.00%
Expected life in years	6 years 4 months 24 days
Expected volatility	42.85%
Risk-free interest rate	0.87%
Grant date fair value per share of option awards	$ 8.42
March 2019 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of stock option award	$ 26.63
Expected dividend yield per share	0.00%
Expected life in years	6 years 1 month 20 days
Expected volatility	39.44%
Risk-free interest rate	2.53%
Grant date fair value per share of option awards	$ 11.29
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 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

Stock-based Compensation - Summary of Status and Activity of Stock Options (Detail) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options, Outstanding at December 31, 2019 \| shares	966,849
Options, Granted \| shares	187,701
Options, Exercised \| shares	(2,500)
Options, Expired \| shares	(5,129)
Options, Forfeited \| shares	(26,667)
Options, Outstanding at December 31, 2020 \| shares	1,120,254
Options, Exercisable at December 31, 2020 \| shares	776,125
Weighted Average Exercise Price per Option, Outstanding at December 31, 2019 \| $ / shares	$ 28.45
Weighted Average Exercise Price per Option, Granted \| $ / shares	19.63
Weighted Average Exercise Price per Option, Exercised \| $ / shares	20.00
Weighted Average Exercise Price per Option, Expired \| $ / shares	31.28
Weighted Average Exercise Price per Option, Forfeited \| $ / shares	32.45
Weighted Average Exercise Price per Option, Outstanding at December 31, 2020 \| $ / shares	26.89
Weighted Average Exercise Price per Option, Exercisable at December 31, 2020 \| $ / shares	$ 27.39
Weighted Average Remaining Contractual Term, Outstanding at December 31, 2020	5 years 4 months 28 days
Weighted Average Remaining Contractual Term, Exercisable at December 31, 2020	4 years 18 days
Aggregate Intrinsic Value, Outstanding at December 31, 2020 \| $	$ 8.6
Aggregate Intrinsic Value, Exercisable at December 31, 2020 \| $	$ 6.0

Stock-based Compensation - Schedule of Stock-Based Compensation Expense Recognized (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Stock-based compensation expense recognized:
Less related income tax benefit	$ 2.2	$ 0.2	$ 3.1
Decrease in net income attributable to Koppers	9.1	11.9	9.4
Intrinsic value of exercised stock options	0.0	1.1	1.1
Cash received from the exercise of stock options	0.0	2.9	2.9
Selling, General and Administrative Expenses [Member]
Stock-based compensation expense recognized:
Stock-based compensation expense	$ 11.3	$ 12.1	$ 12.5

Segment Information - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) Segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments \| Segment	3
Net sales	$ 1,669.1	$ 1,637.0	$ 1,562.7
Non-U.S. Countries [Member]
Segment Reporting Information [Line Items]
Net sales	$ 499.0	$ 495.8	$ 569.2

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8906-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9031-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9038-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130543-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9054-108599

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130545-203045

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI http://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

+ Details

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

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Revenues from external customers:

Net sales

$ 1,669.1

$ 1,637.0

$ 1,562.7

Net sales

1,669.1

1,637.0

1,562.7

Depreciation and amortization expense

54.1

51.4

46.9

Operating profit (loss)

156.7

125.0

84.4

Capital expenditures (excluding acquisitions):

69.8

37.2

109.7

Performance Chemicals [Member]

Revenues from external customers:

Net sales

526.3

448.3

420.0

Net sales

526.3

448.3

420.0

Carbon Materials and Chemicals [Member]

Revenues from external customers:

Net sales

383.7

455.2

507.9

Net sales

383.7

455.2

507.9

Railroad And Utility Products And Services

Revenues from external customers:

Net sales

759.1

733.5

634.8

Net sales

759.1

733.5

634.8

Operating Segments [Member] | Performance Chemicals [Member]

Revenues from external customers:

Net sales

526.3

448.3

420.0

Net sales

526.3

448.3

420.0

Depreciation and amortization expense

18.1

18.3

17.8

Operating profit (loss)

88.6

52.1

36.2

Capital expenditures (excluding acquisitions):

12.1

9.7

15.1

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

Revenues from external customers:

Net sales

^[1]

383.7

455.2

507.9

Net sales

^[1]

383.7

455.2

507.9

Depreciation and amortization expense

^[2]

15.9

13.7

11.4

Operating profit (loss)

^[3]

23.4

39.2

44.7

Capital expenditures (excluding acquisitions):

^[4]

24.8

15.5

73.5

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

Revenues from external customers:

Net sales

759.1

733.5

634.8

Net sales

759.1

733.5

634.8

Depreciation and amortization expense

20.1

19.4

17.7

Operating profit (loss)

^[5]

46.7

35.8

5.9

Capital expenditures (excluding acquisitions):

31.3

11.6

19.2

Intersegment [Member]

Revenues from external customers:

Net sales

92.4

87.8

88.1

Net sales

92.4

87.8

88.1

Intersegment [Member] | Performance Chemicals [Member]

Revenues from external customers:

Net sales

13.7

12.6

10.8

Net sales

13.7

12.6

10.8

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

Revenues from external customers:

Net sales

78.7

75.2

77.3

Net sales

78.7

75.2

77.3

Corporate, Non-Segment

Revenues from external customers:

Operating profit (loss)

^[6]

(2.0)

(2.1)

(2.4)

Capital expenditures (excluding acquisitions):

$ 1.6

$ 0.4

$ 1.9

[1]	Revenue excludes KJCC discontinued operations of $31.6 million, $135.8 million and $147.5 million for the years ended December 31, 2020, 2019 and 2018, respectively.
[2]	Depreciation and amortization expense excludes KJCC discontinued operations of $0.6 million, $3.7 million and $3.9 million for the years ended December 31, 2020, 2019 and 2018, respectively.
[3]	Operating profit (loss) excludes KJCC discontinued operations of $(5.0) million, $5.8 million and $26.0 million for the years ended December 31, 2020, 2019 and 2018, respectively.
[4]	Capital expenditures includes KJCC discontinued operations of $0.6 million, $3.9 million and $3.4 million for the years ended December 31, 2020, 2019 and 2018, respectively.
[5]	Includes $6.0 million of inventory fair value purchase price accounting adjustments from our acquisition of UIP in 2018.
[6]	Operating loss for Corporate includes costs for Koppers Holdings Inc., the parent company of Koppers Inc., and acquisition-related costs.

Segment Information - Summary of Results of Segment Operations (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues from external customers:
Net sales	$ 31.6	$ 135.8	$ 147.5
Depreciation and amortization expense	0.6	3.7	3.9
Operating (loss) profit	(5.0)	5.8	26.0
Operating profit (loss)	156.7	125.0	84.4
Capital expenditure, discontinued operations	$ 0.6	$ 3.9	3.4
Koppers Utility and Industrial Products [Member] \| Inventory Fair Value Purchase Price Adjustment [Member]
Revenues from external customers:
Operating profit (loss)			$ 6.0

Segment Information - Summary of Tangible and Intangible Assets by Segments (Detail) - USD ($)
$ in Millions

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Segment Reporting Asset Reconciling Item [Line Items]

Assets

$ 1,598.6

$ 1,564.6

Cash and cash equivalents

38.5

32.3

$ 37.4

$ 50.9

Income tax receivable

1.2

1.1

Deferred taxes

45.3

44.0

Property, plant and equipment, net

^[1]

409.1

358.8

Operating lease right-of-use assets

102.5

112.3

Goodwill

297.8

296.1

296.5

Operating Segments [Member]

Segment Reporting Asset Reconciling Item [Line Items]

Assets

1,543.4

1,522.0

Corporate, Non-Segment

Segment Reporting Asset Reconciling Item [Line Items]

Cash and cash equivalents

0.4

0.0

Income tax receivable

1.2

1.9

Deferred taxes

28.8

17.0

Property, plant and equipment, net

5.9

5.3

Operating lease right-of-use assets

11.9

13.2

Prepaid insurance and other assets

7.0

5.2

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

Segment Reporting Asset Reconciling Item [Line Items]

Assets

583.1

562.2

Goodwill

121.1

120.7

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

Segment Reporting Asset Reconciling Item [Line Items]

Assets

424.2

502.1

Performance Chemicals [Member]

Segment Reporting Asset Reconciling Item [Line Items]

Goodwill

176.7

175.4

$ 175.4

Performance Chemicals [Member] | Operating Segments [Member]

Segment Reporting Asset Reconciling Item [Line Items]

Assets

536.1

457.7

Goodwill

$ 176.7

$ 175.4

[1]	Net property, plant, and equipment excludes $56.6 million of assets of discontinued operations held for sale related to our KJCC business as of December 31, 2019.

Segment Information - Summary of Tangible and Intangible Assets by Segments ((Parenthetical)) (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Asset Reconciling Item [Line Items]
Fair value		$ 76.4
Discontinued Operations, Held-for-sale \| Carbon Materials and Chemicals [Member]
Segment Reporting Asset Reconciling Item [Line Items]
Fair value	$ 76.4

Segment Information - Schedule of Revenues and Long-Lived Assets by Geographic Area (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Revenues from external customers	$ 1,669.1	$ 1,637.0	$ 1,562.7
Long-lived assets	1,015.7	962.1	865.1
United States [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	1,170.1	1,141.2	993.5
Long-lived assets	832.0	796.0	732.1
Australia [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	194.3	199.6	218.8
Long-lived assets	82.0	76.6	69.8
Europe [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	162.3	177.5	214.6
Long-lived assets	83.2	70.2	44.8
Other Countries [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	142.4	118.7	135.8
Long-lived assets	$ 18.5	$ 19.3	$ 18.3

- Definition

+ References

+ Details

Segment Information - Schedule of Revenues and Long-Lived Assets by Geographic area (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Asset Reconciling Item [Line Items]
Net sales	$ 31.6	$ 135.8	$ 147.5
Discontinued Operations, Held-for-sale \| Carbon Materials and Chemicals [Member]
Segment Reporting Asset Reconciling Item [Line Items]
Fair value		$ 59.3	$ 59.0

Segment Information - Schedule of Segment Revenues for Significant Product Lines (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Net sales	$ 1,669.1	$ 1,637.0	$ 1,562.7
Railroad and Utility Products and Services [Member]
Segment Reporting Information [Line Items]
Net sales	759.1	733.5	634.8
Railroad and Utility Products and Services [Member] \| Railroad Treated Products [Member]
Segment Reporting Information [Line Items]
Net sales	405.1	419.6	341.7
Railroad and Utility Products and Services [Member] \| Utility Poles [Member]
Segment Reporting Information [Line Items]
Net sales	241.7	222.0	184.7
Railroad and Utility Products and Services [Member] \| Rail Joints [Member]
Segment Reporting Information [Line Items]
Net sales	20.3	26.8	33.5
Railroad and Utility Products and Services [Member] \| Railroad Infrastructure Services [Member]
Segment Reporting Information [Line Items]
Net sales	63.5	36.5	36.9
Railroad and Utility Products and Services [Member] \| Other Products [Member]
Segment Reporting Information [Line Items]
Net sales	28.6	28.6	38.0
Carbon Materials and Chemicals [Member]
Segment Reporting Information [Line Items]
Net sales	383.7	455.2	507.9
Carbon Materials and Chemicals [Member] \| Other Products [Member]
Segment Reporting Information [Line Items]
Net sales	26.7	33.7	32.1
Carbon Materials and Chemicals [Member] \| Pitch and Related Products [Member]
Segment Reporting Information [Line Items]
Net sales	230.9	272.4	280.9
Carbon Materials and Chemicals [Member] \| Creosote and Distillates [Member]
Segment Reporting Information [Line Items]
Net sales	40.0	46.3	84.1
Carbon Materials and Chemicals [Member] \| Phthalic Anhydride and Other Chemicals [Member]
Segment Reporting Information [Line Items]
Net sales	66.4	77.9	84.6
Carbon Materials and Chemicals [Member] \| Naphthalene [Member]
Segment Reporting Information [Line Items]
Net sales	19.7	24.9	26.2
Performance Chemicals [Member]
Segment Reporting Information [Line Items]
Net sales	526.3	448.3	420.0
Performance Chemicals [Member] \| Other Products [Member]
Segment Reporting Information [Line Items]
Net sales	15.6	29.5	30.9
Performance Chemicals [Member] \| Wood Preservative Products [Member]
Segment Reporting Information [Line Items]
Net sales	$ 510.7	$ 418.8	$ 389.1

Segment Information - Schedule of Segment Revenues for Significant Product Lines (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting [Abstract]
Net sales	$ 31.6	$ 135.8	$ 147.5

Income Taxes - Summary of Income Tax Provision (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
Federal	$ 0.8	$ (3.5)	$ (1.2)
State	0.7	0.5	0.1
Foreign	11.1	14.4	17.9
Total current tax provision	12.6	11.4	16.8
Deferred:
Federal	6.1	3.1	9.6
State	1.6	0.4	(0.2)
Foreign	0.7	(14.9)	(0.5)
Total deferred tax provision (benefit)	8.4	(11.4)	8.9
Total income tax provision	$ 21.0	$ 0.0	$ 25.7

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Income before income taxes	$ 52.4	$ 69.9	$ 82.3
Federal income tax rate	21.00%	21.00%	21.00%	35.00%
Percentage of limitations on deductibility of interest expense		30.00%
Valuation allowance		$ 13.3	$ 13.3
Percentage Of Allowable Business Interest Expense Deduction From Adjusted Taxable Income	50.00%
Income tax expense (benefit)	$ 21.0	0.0	25.7
Deferred Income Tax Expense Benefit	8.4	(11.4)	8.9
Deferred income tax expense (benefit) relating to copper swap contracts	12.6	4.1	(10.0)
Deferred income tax expense (benefit) relating to unfunded status of employee post-retirement benefit plans	(0.4)	0.7	(0.1)
Unremitted earnings	602.0
Unrecognized tax benefits with impact on the effective tax rate	2.5	2.0
Interest expense (income) and related penalties			1.4
Accrued interest expense and penalties	0.8	0.8
Decrease in unrecognized tax benefits	(1.7)
Dutch legal entity restructuring project [Member]
Income Taxes [Line Items]
Deferred Income Tax Expense Benefit		$ 14.9
Dutch legal entity restructuring project [Member] \| Maximum [Member]
Income Taxes [Line Items]
Finite Lived Intangible Asset Useful Life		14 years
Dutch legal entity restructuring project [Member] \| Minimum [Member]
Income Taxes [Line Items]
Finite Lived Intangible Asset Useful Life		9 years
Reverse Valuation Allowance Carryforward [Member]
Income Taxes [Line Items]
Income tax expense (benefit)	(13.3)
Rate Reduction [Member]
Income Taxes [Line Items]
Income tax benefit revised from prior amount			3.8
Transition Tax [Member]
Income Taxes [Line Items]
Additional income tax expense due to guidance issued by IRS			8.6
Tax cuts and jobs act of 2017 one time transition tax cash payment	5.1
GILTI Tax [Member]
Income Taxes [Line Items]
Tax Cuts And Jobs Act Of2017 Provision For Income Tax Expense	$ 4.4	$ 0.9	$ 6.6

Income Taxes - Summary of Income Taxes Reconciled with Federal Statutory Rate (Detail)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Federal income tax rate	21.00%	21.00%	21.00%	35.00%
GILTI inclusion, net of foreign tax credits	4.00%	1.40%	21.10%
Foreign earnings taxed at different rates	2.90%	(0.20%)	0.40%
State income taxes, net of federal tax benefit	2.20%	1.10%	(5.90%)
Transition tax from Tax Act	0.00%	0.00%	27.30%
Deferred tax adjustments from Tax Act	0.00%	0.00%	(12.00%)
Intra-entity transfer of intangible assets	0.000	(0.234)	0.000
Change in tax contingency reserves	(0.20%)	(7.00%)	(3.50%)
Deferred tax adjustments	(2.20%)	0.00%	4.00%
Valuation allowance adjustments	(12.10%)	9.10%	28.80%
Other	3.50%	(2.00%)	1.20%
Total effective tax rate	19.10%	0.00%	82.40%

Income Taxes - Summary of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Tax credits	$ 20.0	$ 22.5
Federal and state tax loss carryforwards, expiring from 2020 to 2039	18.3	17.8
Reserves, including insurance and environmental	11.7	23.3
Pension and other postretirement benefits obligations	9.7	9.4
Foreign tax loss carryforwards	7.5	5.6
Asset retirement obligations	6.8	6.5
Accrued employee compensation	6.6	8.5
Book/tax inventory accounting differences	6.2	5.1
Other	3.1	3.3
Valuation allowance	(44.6)	(58.0)
Total deferred tax assets	45.3	44.0
Deferred tax liabilities:
Tax over book depreciation and amortization	28.1	25.5
Gain on derivative contracts	16.3	1.4
Other	3.8	0.2
Total deferred tax liabilities	48.2	27.1
Net deferred tax (liabilities) assets	$ 2.9	$ 16.9

Income Taxes - Summary of Valuation Allowances Recorded to Offset Deferred Tax Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Income Taxes [Line Items]
Total valuation allowances	$ 44.6	$ 58.0
Foreign [Member] \| Tax Credits [Member]
Income Taxes [Line Items]
Total valuation allowances	18.8	20.5
Foreign [Member] \| Operating Losses and Capital Losses [Member]
Income Taxes [Line Items]
Total valuation allowances	6.7	6.1
State [Member] \| Operating Losses and Tax Credits [Member]
Income Taxes [Line Items]
Total valuation allowances	19.1	18.1
Federal [Member]
Income Taxes [Line Items]
Total valuation allowances	$ 0.0	$ 13.3

Income taxes - Summary of Unrecognized Tax Benefits (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 2.1	$ 7.0	$ 8.7
Additions based on tax provisions related to the current year	0.2	0.1	0.1
Additions for tax provisions of prior years	0.5	0.0	0.0
Reductions resulting from a lapse in the statute of limitations	(0.3)	(0.3)	(0.3)
Reductions of tax provisions of prior years	(0.0)	(1.8)	(1.5)
Reductions resulting from audit closures	(0.0)	(2.9)	(0.0)
Balance at end of year	$ 2.5	$ 2.1	$ 7.0

Inventories - Components of Inventories (Detail) - USD ($)
$ in Millions

Dec. 31, 2020

Dec. 31, 2019

Inventory Disclosure [Abstract]

Raw materials

$ 233.7

$ 232.0

Work in process

12.4

12.0

Finished goods

99.3

107.8

Inventories, gross

345.4

351.8

Less revaluation to LIFO

49.6

63.3

Inventories, net

^[1]

$ 295.8

$ 288.5

[1]	Net inventories excludes $10.6 million of assets of discontinued operations held for sale related to our KJCC business as of December 31, 2019

Inventories - Components of Inventories (Parenthetical) (Detail) - USD ($)
$ in Millions

Dec. 31, 2020

Dec. 31, 2019

Inventory [Line Items]

Inventories, net

^[1]

$ 295.8

$ 288.5

Koppers (Jiangsu) Carbon Chemical Company Limited [Member]

Inventory [Line Items]

Inventories, net

$ 10.6

[1]	Net inventories excludes $10.6 million of assets of discontinued operations held for sale related to our KJCC business as of December 31, 2019

Property, Plant and Equipment - Property, Plant and Equipment (Detail) - USD ($)
$ in Millions

Dec. 31, 2020

Dec. 31, 2019

Property, Plant and Equipment [Line Items]

Property, plant and equipment, gross

$ 903.8

$ 817.9

Less accumulated depreciation

494.7

459.1

Property, Plant and Equipment, net

^[1]

409.1

358.8

Land [Member]

Property, Plant and Equipment [Line Items]

Property, plant and equipment, gross

16.7

15.0

Buildings [Member]

Property, Plant and Equipment [Line Items]

Property, plant and equipment, gross

75.0

70.5

Machinery and Equipment [Member]

Property, Plant and Equipment [Line Items]

Property, plant and equipment, gross

$ 812.1

$ 732.4

[1]	Net property, plant, and equipment excludes $56.6 million of assets of discontinued operations held for sale related to our KJCC business as of December 31, 2019.

Property, Plant and Equipment - Property, Plant and Equipment (Parenthetical) (Detail) $ in Millions	Dec. 31, 2019 USD ($)
Property, Plant and Equipment [Line Items]
Fair value	$ 76.4
Koppers (Jiangsu) Carbon Chemical Company Limited [Member]
Property, Plant and Equipment [Line Items]
Fair value	$ 56.6

Property, Plant and Equipment - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Depreciation expense	$ 33,700,000	$ 30,700,000	$ 27,700,000
Depreciation Expense Excludes KJCC Discontinued Operations	600,000	3,700,000	3,900,000
Impairment charges	$ 0	$ 0	$ 0

Goodwill and Other Identifiable Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Acquired Finite-Lived Intangible Assets [Line Items]
Balance beginning	$ 296.1	$ 296.5
Purchase accounting adjustment		(0.4)
Currency translation	1.7
Balance ending	297.8	296.1
Performance Chemicals [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Balance beginning	175.4	175.4
Purchase accounting adjustment		0.0
Currency translation	1.3
Balance ending	176.7	175.4
Railroad Products and Services [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Balance beginning	41.0	41.0
Purchase accounting adjustment		0.0
Currency translation	0.1
Balance ending	41.1	41.0
Utility Products [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Balance beginning	79.7	80.1
Purchase accounting adjustment		(0.4)
Currency translation	0.3
Balance ending	$ 80.0	$ 79.7

Goodwill and Other Identifiable Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill impairment charge	$ 0	$ 0	$ 0
Increase in carrying value of identifiable intangible assets	2,300,000
Amortization expense	$ 19,800,000	$ 20,700,000	$ 19,200,000

Goodwill and Other Identifiable Intangible Assets - Schedule of Identifiable Intangible Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average remaining life in years	9 years 1 month 6 days
Gross Carrying Amount	$ 268.3	$ 266.0
Accumulated Amortization	118.5	97.6
Net	$ 149.8	168.4
Customer Contracts [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average remaining life in years	9 years 6 months
Gross Carrying Amount	$ 228.5	227.0
Accumulated Amortization	84.7	69.5
Net	$ 143.8	157.5
Customer Contracts [Member] \| Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	9 years
Customer Contracts [Member] \| Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	18 years
Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average remaining life in years	1 year 10 months 24 days
Gross Carrying Amount	$ 26.8	26.7
Accumulated Amortization	23.6	19.9
Net	$ 3.2	6.8
Technology [Member] \| Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	4 years
Technology [Member] \| Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	12 years
Trademarks [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average remaining life in years	5 years 1 month 6 days
Gross Carrying Amount	$ 7.9	7.6
Accumulated Amortization	5.8	4.4
Net	$ 2.1	3.2
Trademarks [Member] \| Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	2 years
Trademarks [Member] \| Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	17 years
Supply Contracts [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	10 years
Weighted average remaining life in years	0 years
Gross Carrying Amount	$ 2.6	2.4
Accumulated Amortization	2.6	2.3
Net	$ 0.0	0.1
Non-Compete Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	12 years
Weighted average remaining life in years	3 years 9 months 18 days
Gross Carrying Amount	$ 1.7	1.6
Accumulated Amortization	1.0	0.8
Net	$ 0.7	0.8
Favorable Lease Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated life in years	3 years
Weighted average remaining life in years	0 years
Gross Carrying Amount	$ 0.8	0.7
Accumulated Amortization	0.8	0.7
Net	$ 0.0	$ 0.0

Goodwill and Other Identifiable Intangible Assets - Schedule of Future Amortization Expense (Detail) $ in Millions	Dec. 31, 2020 USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
2021	$ 17.7
2022	15.0
2023	14.6
2024	14.3
2025	$ 13.8

Pensions and Post-Retirement Benefit Plans - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) Plan	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Number of domestic non-qualified defined benefit plans \| Plan	3
Defined contribution plan expense	$ 8.4	$ 8.3	$ 7.5
Net actuarial loss	17.3
Benefit obligation	56.5
Plan assets	68.2
Accumulated benefit obligation, pension plans	232.5	219.0
Operating expenses	$ 17.3	12.2	10.3
Growth seeking assets [Member] \| Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation investment strategy	30.00%
Growth seeking assets [Member] \| Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation investment strategy	40.00%
Income generating assets [Member] \| Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation investment strategy	60.00%
Income generating assets [Member] \| Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation investment strategy	70.00%
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ (17.3)	(20.1)
Benefit obligation	233.3	219.8	201.7
Expected contributions by employer	1.0
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	(1.3)	0.3
Benefit obligation	10.5	$ 9.2	$ 9.4
Expected contributions by employer	$ 0.7
Salaried and Hourly Employees [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of domestic non-qualified defined benefit plans \| Plan	2

Pensions and Post-Retirement Benefit Plans - Components of Net Periodic Benefit Cost for Pension Plans and Other Benefit Plans (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1.4	$ 1.5	$ 1.9
Interest cost	6.4	7.8	7.5
Expected return on plan assets	(7.9)	(7.9)	(8.5)
Amortization of net loss (gain)	1.7	1.6	1.4
Settlements and curtailments	0.1	(0.0)	(0.0)
Net periodic benefit cost	1.7	3.0	2.3
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.1	0.1	0.1
Interest cost	0.3	0.4	0.4
Expected return on plan assets	(0.0)	(0.0)	(0.0)
Amortization of net loss (gain)	(0.2)	(0.2)	(0.0)
Settlements and curtailments	(0.0)	(0.0)	(0.0)
Net periodic benefit cost	$ 0.2	$ 0.3	$ 0.5

Pensions and Post-Retirement Benefit Plans - Schedule of Change in Funded Status of Pension and Post-Retirement Plans (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Actuarial losses (gains)	$ (17.3)
Benefit obligation at end of year	56.5
Fair value of plan assets at beginning of year	191.5
Fair value of plan assets at end of year	208.0	$ 191.5
Noncurrent liabilities	46.2	46.6
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	219.8	201.7
Service cost	1.4	1.5	$ 1.9
Interest cost	6.4	7.8	7.5
Actuarial losses (gains)	17.3	20.1
Settlements	(2.2)	(0.0)
Currency translation	2.6	1.6
Benefits paid	(12.0)	(12.9)
Benefit obligation at end of year	233.3	219.8	201.7
Fair value of plan assets at beginning of year	191.5	169.6
Actual return on plan assets	23.6	28.6
Employer contribution	3.9	4.2
Currency translation	3.2	2.0
Benefits paid	(12.0)	(12.9)
Fair value of plan assets at end of year	208.0	191.5	169.6
Funded status of the plan	(25.3)	(28.3)
Noncurrent assets	12.1	10.9
Current liabilities	1.0	1.0
Noncurrent liabilities	36.4	38.2
Benefit obligation	172.5	160.4
Fair value of plan assets	135.0	121.2
Accumulated benefit obligation	172.2	160.2
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	9.2	9.4
Service cost	0.1	0.1	0.1
Interest cost	0.3	0.4	0.4
Actuarial losses (gains)	1.3	(0.3)
Settlements	(0.0)	(0.0)
Currency translation	0.0	0.0
Benefits paid	(0.4)	(0.3)
Benefit obligation at end of year	10.5	9.2	9.4
Fair value of plan assets at beginning of year	0.0	0.0	0.0
Actual return on plan assets	0.0	0.0
Employer contribution	0.4	0.3
Currency translation	0.0	0.0
Benefits paid	(0.4)	(0.3)
Fair value of plan assets at end of year		0.0	0.0
Funded status of the plan		(9.2)	$ (10.5)
Noncurrent assets	0.0	0.0
Current liabilities	0.7	0.8
Noncurrent liabilities	$ 9.8	$ 8.4

Pensions and Post-Retirement Benefit Plans - Schedule of Projected Benefit Payments (Detail) $ in Millions	Dec. 31, 2020 USD ($)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2021	$ 11.6
2022	11.4
2023	11.5
2024	11.6
2025	12.1
Next five years	59.8
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2021	0.7
2022	0.7
2023	0.7
2024	0.6
2025	0.6
Next five years	$ 3.0

Pensions and Post-Retirement Benefit Plans - Schedule of Weighted-Average Assumptions (Detail)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.29%	3.05%
Expected return on plan assets	3.67%	4.30%
Rate of compensation increase	3.41%	3.00%
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate		3.43%	2.66%
Initial medical trend rate			5.40%	5.70%

Pensions and Post-Retirement Benefit Plans - Schedule of Weighted Average Asset Allocation for Company's Pension Plans (Detail)	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
December 31,	100.00%	100.00%
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
December 31,	70.00%	70.00%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
December 31,	21.00%	24.00%
Other [Member]
Defined Benefit Plan Disclosure [Line Items]
December 31,	9.00%	6.00%

Pensions and Post-Retirement Benefit Plans - Schedule of Pension Plan Assets at Fair Value (Detail) - USD ($)
$ in Millions

Dec. 31, 2020

Dec. 31, 2019

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

$ 208.0

$ 191.5

Investments measured at NAV

^[1]

37.5

40.0

Fair Value, Recurring

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

170.5

151.5

Fair Value, Recurring | Quoted prices in active markets for identical assets (Level 1) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

0.0

Fair Value, Recurring | Significant observable inputs (Level 2) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

170.5

147.2

Fair Value, Recurring | Significant unobservable inputs (Level 3) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

0.0

4.3

Fair Value, Recurring | U.S. equity securities [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

8.1

14.1

Fair Value, Recurring | U.S. equity securities [Member] | Quoted prices in active markets for identical assets (Level 1) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

0.0

Fair Value, Recurring | U.S. equity securities [Member] | Significant observable inputs (Level 2) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

8.1

14.1

Fair Value, Recurring | U.S. equity securities [Member] | Significant unobservable inputs (Level 3) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

0.0

Fair Value, Recurring | International equity securities [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

19.3

22.3

Fair Value, Recurring | International equity securities [Member] | Quoted prices in active markets for identical assets (Level 1) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

0.0

Fair Value, Recurring | International equity securities [Member] | Significant observable inputs (Level 2) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

19.3

22.3

Fair Value, Recurring | International equity securities [Member] | Significant unobservable inputs (Level 3) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

0.0

Fair Value, Recurring | U.S. debt securities [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

68.6

58.3

Fair Value, Recurring | U.S. debt securities [Member] | Quoted prices in active markets for identical assets (Level 1) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

0.0

Fair Value, Recurring | U.S. debt securities [Member] | Significant observable inputs (Level 2) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

68.6

58.3

Fair Value, Recurring | U.S. debt securities [Member] | Significant unobservable inputs (Level 3) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

0.0

Fair Value, Recurring | International debt securities [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

62.7

48.1

Fair Value, Recurring | International debt securities [Member] | Quoted prices in active markets for identical assets (Level 1) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

0.0

Fair Value, Recurring | International debt securities [Member] | Significant observable inputs (Level 2) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

62.7

48.1

Fair Value, Recurring | International debt securities [Member] | Significant unobservable inputs (Level 3) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

0.0

Fair Value, Recurring | Real estate and other investments [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

0.6

5.1

Fair Value, Recurring | Real estate and other investments [Member] | Quoted prices in active markets for identical assets (Level 1) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

0.0

Fair Value, Recurring | Real estate and other investments [Member] | Significant observable inputs (Level 2) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

0.6

0.8

Fair Value, Recurring | Real estate and other investments [Member] | Significant unobservable inputs (Level 3) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

0.0

4.3

Fair Value, Recurring | Cash & Cash Equivalents [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

11.2

3.6

Fair Value, Recurring | Cash & Cash Equivalents [Member] | Quoted prices in active markets for identical assets (Level 1) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

0.0

Fair Value, Recurring | Cash & Cash Equivalents [Member] | Significant observable inputs (Level 2) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

11.2

3.6

Fair Value, Recurring | Cash & Cash Equivalents [Member] | Significant unobservable inputs (Level 3) [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair value of pension plan assets

$ 0.0

[1]	The fair value amounts presented in the table above are intended to permit reconciliations of the fair value hierarchy to the total plan assets.

Pensions and Post-Retirement Benefit Plans - Summary of Changes in Fair Value of Pension Plan Assets (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	$ 191.5
Fair value of plan assets at end of year	208.0
Level 3 [Member] \| Other Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	4.3
Purchases, sales, issuances and settlements	(4.3)
Fair value of plan assets at end of year	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	$ 0.0

- Definition

Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

+ References + Details

Debt - Schedule of Long-Term Debt Instruments (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Total debt	$ 784.2	$ 911.9
Less short-term debt and current maturities of long-term debt	10.1	10.2
Less unamortized debt issuance costs	8.3	10.7
Long-term debt	$ 765.8	891.0
Term Loan [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	2.69%
Debt, Maturity	2024
Total debt	$ 12.2	82.5
Senior Secured Credit Facilities [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	2.69%
Debt, Maturity	2024
Total debt	$ 272.0	329.4
6.00 percent Senior Notes due 2025 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	6.00%
Debt, Maturity	2025
Total debt	$ 500.0	$ 500.0

Debt - Additional Information (Detail) - USD ($)		12 Months Ended
Debt - Additional Information (Detail) - USD ($)	Feb. 15, 2022	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Accumulated amortization		$ 9,400,000	$ 6,800,000
Unamortized debt issuance costs		8,300,000	$ 10,700,000
Senior Secured Credit Facilities [Member]
Debt Instrument [Line Items]
Letters of credit, amount outstanding		$ 7,700,000
6.00 percent Senior Notes due 2025 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Senior notes, payment terms		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.
Debt instrument, redemption price percentage		104.50%
Debt maturity date		Feb. 15, 2025
6.00 percent Senior Notes due 2025 [Member] \| Scenario, Forecast [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, redemption price percentage	101.50%
Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line Of Credit Facility Maximum Borrowing Capacity		$ 600,000,000.0
Revolving credit facility, variable interest rate basis		LIBOR
Secured Term Loan Facility [Member]
Debt Instrument [Line Items]
Secured Long Term Debt		$ 100,000,000.0
Quarterly amortization		2,500,000
Revolving Credit Facility [Member] \| Senior Secured Credit Facilities [Member]
Debt Instrument [Line Items]
Debt instrument, unused borrowing capacity		$ 307,800,000

Debt - Schedule of Debt Maturities (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
2021	$ 10.1
2022	2.1
2023	0.0
2024	272.0
2025	500.0
Total debt	$ 784.2	$ 911.9

Leases - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease costs	$ 31.2	$ 31.8
Variable lease costs	$ 3.5	$ 3.7

Leases - Summary of Amount and Timing of Cash Flows From Operating Leases (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
2021	$ 28.4
2022	24.6
2023	19.2
2024	15.4
2025	12.3
Thereafter	33.5
Total lease payments	133.5
Less: Interest	(31.0)
Present value of lease liabilities	$ 102.5	$ 113.5

Leases - Schedule of Supplemental Consolidated Balance Sheet Information Related to Leases (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Operating leases:
Operating lease right-of-use assets	$ 102.5	$ 112.3
Current operating lease liabilities	21.2	22.0
Operating lease liabilities	81.3	91.5
Total operating lease liabilities	$ 102.5	$ 113.5
Weighted average remaining lease term, in years	6 years 4 months 24 days	6 years 10 months 24 days
Weighted average discount rate	7.50%	7.70%

Derivative Financial Instruments - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Maximum period hedged in cash flow hedge	36 months
Unrealized gains, reclassification period	12 months
Unrealized gains, net of tax, expected to be reclassified from other comprehensive (loss) income into earnings	$ 23.1

Derivative Financial Instruments - Schedule of Outstanding Copper Swap Contracts (Detail) - Copper Swap Contracts [Member] £ in Millions, $ in Millions	Dec. 31, 2020 USD ($)	Dec. 31, 2020 GBP (£)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 GBP (£)
Derivatives Fair Value [Line Items]
Copper Swap Contracts Units Outstanding \| £		£ 73.8		£ 73.1
Net Fair Value - Asset (Liability) \| $	$ 69.2		$ 6.2
Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Derivatives Fair Value [Line Items]
Copper Swap Contracts Units Outstanding \| £		62.3		56.5
Net Fair Value - Asset (Liability) \| $	58.3		4.5
Not Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Copper Swap Contracts Units Outstanding \| £		£ 11.5		£ 16.6
Net Fair Value - Asset (Liability) \| $	$ 10.9		$ 1.7

Derivative Financial Instruments - Schedule of Fair Value of Outstanding Copper Swap Contracts Recorded in Balance Sheet (Detail) - Copper Swap Contracts [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Derivative [Line Items]
Net Fair Value - Asset (Liability)	$ 69.2	$ 6.2
Accumulated other comprehensive gain, net of tax	44.4	3.2
Derivative Contracts [Member]
Derivative [Line Items]
Net Fair Value - Asset (Liability)	37.3	2.1
Non Current Derivative Contracts [Member]
Derivative [Line Items]
Net Fair Value - Asset (Liability)	$ 31.9	$ 4.1

Derivative Financial Instruments - Schedule of Amounts Recognized In Earnings Related To Copper Swap Contracts (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Copper Swap Contracts [Member]
Derivative [Line Items]
Gain from contracts not designated as hedges	$ 9.2	$ 4.1

Derivative Financial Instruments - Schedule of Fair Value of Outstanding Foreign Currency Forward Contracts (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Derivative [Line Items]
Not designated gross derivative liability	$ 0.7	$ (0.2)
Forward Contracts [Member] \| Accrued Liabilities [Member]
Derivative [Line Items]
Not designated gross derivative liability	(0.5)	(0.5)
Forward Contracts [Member] \| Derivative Contracts [Member]
Derivative [Line Items]
Not designated gross derivative liability	$ 1.2	$ 0.3

Derivative Financial Instruments - Summary of Net Currency Units Outstanding (Detail)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 GBP (£)	Dec. 31, 2020 NZD ($)	Dec. 31, 2020 EUR (€)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 GBP (£)	Dec. 31, 2019 NZD ($)	Dec. 31, 2019 EUR (€)
Offsetting [Abstract]
Net currency units outstanding	$ 7,600,000	£ 2,000,000	$ 0	€ 0	$ 6,200,000	£ 3,700,000	$ 16,000,000	€ 1,200,000

Common Stock and Senior Convertible Preferred Stock - Schedule of Changes in Senior Convertible Preferred Stock, Common Stock and Treasury Stock (Detail) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity [Abstract]
Senior Convertible Preferred Stock, balance at beginning and end of year	0	0	0
Common Stock, balance at beginning of year	23,321,087	23,029,000	22,384,000
Common Stock, issued for employee stock plans	367,000	292,000	645,000
Common Stock, balance at end of year	23,688,347	23,321,087	23,029,000
Treasury Stock, balance at beginning of year	(2,515,925)	(2,480,000)	(1,606,000)
Treasury Stock, shares repurchased	(74,000)	(36,000)	(874,000)
Treasury Stock, balance at end of year	(2,589,803)	(2,515,925)	(2,480,000)

Commitments and Contingent Liabilities - Additional Information (Detail)	1 Months Ended	12 Months Ended
	Feb. 28, 2021 USD ($)	Dec. 31, 2020 USD ($) State Plaintiff Case site Party Plant	Dec. 31, 2019 USD ($) Plaintiff Case	Dec. 31, 2018 USD ($)
Loss Contingencies [Line Items]
Number of states with new claims filed \| State		2
Number of plaintiffs \| Plaintiff		64	64
Environmental remediation and regulation liability		$ 11,000,000.0	$ 9,500,000	$ 10,100,000
Accrued liability for environmental matters, current		2,900,000	$ 2,800,000
Portland Harbor and Newark Bay CERCLA sites [Member]
Loss Contingencies [Line Items]
Costs of participating in PRP group		3,600,000
Environment Protection Authority [Member]
Loss Contingencies [Line Items]
Reserve for legal proceedings		$ 1,000,000.0
Beazer East [Member]
Loss Contingencies [Line Items]
Sites listed on National Priorities List \| site		1
Compensatory Damages [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		34
Punitive Damages [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		29
Indemnification Agreement [Member] \| Beazer East [Member]
Loss Contingencies [Line Items]
Environmental remediation costs paid by others, per year		$ 6,400,000
Coal Tar Pitch Cases [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		34	34
Reserve for legal proceedings		$ 0
Pennsylvania [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		33
Pennsylvania [Member] \| Coal Tar Pitch Cases [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		33
Tennessee [Member] \| Coal Tar Pitch Cases [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		1
Compensatory damages		$ 15,000,000.0
Oregon [Member]
Loss Contingencies [Line Items]
Number of potential responsible parties \| Party		80
Net present value of selected remedy estimation		$ 1,100,000,000
Undiscounted cost of selected remedy estimation		$ 1,700,000,000
United States [Member]
Loss Contingencies [Line Items]
Environmental remediation and regulation liability			$ 4,300,000
United States [Member] \| Performance Chemicals [Member]
Loss Contingencies [Line Items]
Number of plant sites \| Plant		2
United States [Member] \| Utility and Industrial Products [Member]
Loss Contingencies [Line Items]
Number of plant sites \| Plant		1
New South Wales [Member] \| Environment Protection Authority [Member] \| Subsequent Event [Member]
Loss Contingencies [Line Items]
Gain (loss) related to litigation settlement	$ (100,000)
Australia [Member] \| Performance Chemicals [Member]
Loss Contingencies [Line Items]
Environmental remediation and regulation liability		$ 1,500,000

Commitments and Contingent Liabilities - Changes in Accrued Liability for Environmental Matters (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Balance at beginning of year	$ 9.5	$ 10.1
Expense	1.8	0.5
Revision of reserves	0.0	(0.8)
Cash expenditures	(0.4)	(0.3)
Currency translation	0.1	0.0
Balance at end of period	$ 11.0	$ 9.5

Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$ 2.6	$ 2.5	$ 2.5
Increase (Decrease) to Expense	0.2	0.6	0.7
Net Write-Offs	(0.2)	(0.5)	(0.7)
Currency Translation	0.0	0.0	0.0
Balance at End of Year	2.6	2.6	2.5
Deferred Tax Valuation Allowance [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	58.0	59.9	44.5
Increase (Decrease) to Expense	(12.1)	3.3	15.8
Net Write-Offs	(1.7)	(5.2)	(0.0)
Currency Translation	0.4	0.0	(0.4)
Balance at End of Year	$ 44.6	$ 58.0	$ 59.9