Koppers (KOP) 10-Q 6 Aug 15 2015 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2015	Jul. 31, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q2
Trading Symbol	KOP
Entity Registrant Name	Koppers Holdings Inc.
Entity Central Index Key	1,315,257
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		20,553,284

Condensed Consolidated Statemen

Condensed Consolidated Statement of Operations - USD ($) shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Statement [Abstract]
Net sales	$ 431.6	$ 356.8	$ 829.4	$ 688.2
Cost of sales (excluding items below)	356.8	311.9	700.3	597
Depreciation and amortization	17.7	9.7	32.7	18.6
Gain on sale of business	0	0	(3.2)	0
Impairment and restructuring charges	0	0	2.7	15.5
Selling, general and administrative expenses	31.1	21.9	62.9	43.3
Operating (loss) profit	26	13.3	34	13.8
Other income (loss)	0.2	(0.3)	0.4	(0.1)
Interest expense	12.9	6.6	25.9	13.4
Income before income taxes	13.3	6.4	8.5	0.3
Income tax provision (benefit)	5.4	5.6	4.8	(0.4)
Income (loss) from continuing operations	7.9	0.8	3.7	0.7
Loss from discontinued operations, net of tax benefit of $0.0, $0.1, $0.0 and $0.1	0	(0.1)	0	(0.1)
Net (loss) income	7.9	0.7	3.7	0.6
Net loss attributable to noncontrolling interests	(1.1)	(0.9)	(1.9)	(3.2)
Net income (loss) attributable to Koppers	$ 9	$ 1.6	$ 5.6	$ 3.8
Earnings per common share attributable to Koppers common shareholders:
Basic	$ 0.44	$ 0.08	$ 0.28	$ 0.19
Diluted	$ 0.44	$ 0.08	$ 0.27	$ 0.19
Comprehensive income (loss)	$ 11.1	$ 3.2	$ (3.1)	$ 5.8
Comprehensive loss attributable to noncontrolling interests	(1.1)	(0.9)	(1.9)	(3.6)
Comprehensive income (loss) attributable to Koppers	$ 12.2	$ 4.1	$ (1.2)	$ 9.4
Weighted average shares outstanding (in thousands):
Basic	20,545	20,475	20,529	20,430
Diluted	20,640	20,582	20,603	20,584
Dividends declared per common share	$ 0	$ 0.25	$ 0	$ 0.50

Condensed Consolidated Stateme3

Condensed Consolidated Statement of Operations (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Statement [Abstract]
Loss from discontinued operations, tax benefit	$ 0	$ 0.1	$ 0	$ 0.1

Condensed Consolidated Balance

Condensed Consolidated Balance Sheet - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Assets
Cash and cash equivalents	$ 51.2	$ 51.1
Accounts receivable, net of allowance of $5.8 and $5.6	204.8	198.7
Income tax receivable	1.8	0
Inventories, net	223.4	241.2
Deferred tax assets	13.6	10.5
Loan to related party	9.5	9.5
Other current assets	33.9	30.3
Total current assets	538.2	541.3
Equity in non-consolidated investments	3.9	5
Property, plant and equipment, net	291.9	299.7
Goodwill	256.6	247.2
Intangible assets, net	165.2	167.7
Deferred tax assets	8.3	7.8
Other assets	26	25.2
Total assets	1,290.1	1,293.9
Liabilities
Accounts payable	170.8	120.6
Accrued liabilities	95.3	122.5
Dividends payable	0	5.1
Current maturities of long-term debt	45.4	43.9
Total current liabilities	311.5	292.1
Long-term debt	748.8	806.6
Accrued postretirement benefits	54.1	54.7
Deferred tax liabilities	9.5	10.2
Other long-term liabilities	87.3	46.4
Total liabilities	$ 1,211.2	$ 1,210
Commitments and contingent liabilities (Note 18)
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; 22,012,120 and 21,722,492 shares issued	0.2	0.2
Additional paid-in capital	166.3	164.5
Retained earnings	23.7	18
Accumulated other comprehensive loss	(67.1)	(60.3)
Treasury stock, at cost, 1,458,837 and 1,390,494 shares	(52.7)	(52.4)
Total Koppers shareholders' equity	70.4	70
Noncontrolling interests	8.5	13.9
Total equity	78.9	83.9
Total liabilities and equity	$ 1,290.1	$ 1,293.9

Condensed Consolidated Balance5

Condensed Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Accounts receivable, allowance	$ 5.8	$ 5.6
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	22,012,120	21,722,492
Treasury stock, shares	1,458,837	1,390,494

Condensed Consolidated Stateme6

Condensed Consolidated Statement of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash provided by (used in) operating activities:
Net income	$ 3.7	$ 0.6
Adjustments to reconcile net cash provided by operating activities:
Depreciation and amortization	32.7	18.6
Impairment charges	2.7	4.7
Gain on sale of assets and businesses	(3.2)	0
Deferred income taxes	(0.6)	(6.6)
Equity income, net of dividends received	1.1	0.4
Change in other liabilities	0.1	(8.2)
Non-cash interest expense	1.8	0.8
Stock-based compensation	2	3.2
Deferred revenue	29	0
Other	0.5	0.6
Changes in working capital:
Accounts receivable	(10.5)	(0.3)
Inventories	4.5	(1.8)
Accounts payable	44.2	(15.8)
Accrued liabilities and other working capital	(29.9)	(4.9)
Net cash provided by (used in) operating activities	78.1	(8.7)
Cash (used in) provided by investing activities:
Capital expenditures	(17.3)	(35.6)
Acquisitions, net of cash acquired	(15.3)	(29.6)
Net cash proceeds from divestitures and asset sales	12.5	0
Net cash (used in) provided by investing activities	(20.1)	(65.2)
Cash provided by (used in) financing activities:
Borrowings of revolving credit	299.6	138
Repayments of revolving credit	(342.8)	(113.7)
Borrowings of long-term debt	1.6	31.2
Repayments of long-term debt	(15)	0
Issuances of Common Stock	0	0.7
Proceeds from issuance of noncontrolling interest	0	1.4
Repurchases of Common Stock	(0.3)	(2)
Payment of deferred financing costs	(1)	0
Dividends paid	(8.7)	(10.2)
Net cash (used in) provided by financing activities	(66.6)	45.4
Effect of exchange rate changes on cash	8.7	0.7
Net increase (decrease) in cash and cash equivalents	0.1	(27.8)
Cash and cash equivalents at beginning of period	51.1	82.2
Cash and cash equivalents at end of period	$ 51.2	$ 54.4

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	1. Basis of Presentation The accompanying unaudited condensed consolidated financial statements and related disclosures have been prepared in accordance with accounting principles generally accepted in the United States applicable to interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments considered necessary for a fair presentation of Koppers Holdings Inc.’s and its subsidiaries’ (“Koppers”, “Koppers Holdings” or the “Company”) financial position and interim results as of and for the periods presented have been included. All such adjustments are of a normal recurring nature unless disclosed otherwise. Because the Company’s business is seasonal, results for interim periods are not necessarily indicative of those that may be expected for a full year. The Condensed Consolidated Balance Sheet for December 31, 2014 has been summarized from the audited balance sheet contained in the Annual Report on Form 10-K for the year ended December 31, 2014. The financial information included herein should be read in conjunction with the Company’s audited consolidated financial statements and related notes included in its Annual Report on Form 10-K for the year ended December 31, 2014.

New Accounting Pronouncements

New Accounting Pronouncements	6 Months Ended
	Jun. 30, 2015
Accounting Changes and Error Corrections [Abstract]
New Accounting Pronouncements	2. New Accounting Pronouncements In May 2015, the Financial Accounting Standards Board (“FASB”) issued guidance that removes from the fair value hierarchy investments for which fair value is measured at net asset value (or its equivalent) using the available practical expedient. The new guidance also modifies the scope of the disclosures related to such investments, eliminating from scope those investments eligible for but not actually valued using the practical expedient. Entities must continue to disclose information on investments for which fair value is measured at net asset value (or its equivalent) using the practical expedient, including information that helps readers understand the investments and whether the investments, if sold, are probable of being sold at amounts that differ from the net asset value. This guidance becomes effective January 1, 2016 and requires retrospective application. Early adoption is permitted. We are currently evaluating the impact this guidance will have on disclosures covering certain assets held by our pension plans. In April 2015, the FASB issued Accounting Standards Update (“ASU”) No. 2015-03, “Simplifying the Presentation of Debt Issuance Costs,” which requires companies to present debt issuance costs associated with a debt liability as a deduction from the carrying amount of that debt liability on the balance sheet rather than being capitalized as an asset. The standard is effective for interim and annual periods beginning after December 15, 2015, and retrospective presentation is required. The Company will adopt ASU No. 2015-03 on January 1, 2016 as required. ASU No. 2015-03 will not have a material effect on the Company’s results of operations, financial condition or liquidity. In February 2015, the FASB released updated consolidation guidance that entities must use to evaluate specific ownership and contractual arrangements that lead to a consolidation conclusion. The updates could change consolidation outcomes affecting presentation and disclosures. This guidance becomes effective January 1, 2016. We are currently evaluating the impact this guidance will have on our consolidated financial statements. In August 2014, the FASB issued ASU No. 2014-15, “Disclosure of Uncertainties About an Entity’s Ability to Continue as a Going Concern”, which requires management to perform interim and annual assessments of an entity’s ability to continue as a going concern within one year of the date the financial statements are issued and provides guidance on determining when and how to disclose going concern uncertainties in the financial statements. Certain disclosures will be required if conditions give rise to substantial doubt about an entity’s ability to continue as a going concern. ASU No. 2014-15 applies to all entities and is effective for annual and interim reporting periods ending after December 15, 2016, with early adoption permitted. We do not expect that the adoption of this standard will have a material effect on the Company’s financial statements. In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 requires an entity to recognize revenue in a manner that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, the amendment provides five steps that an entity should apply when recognizing revenue. The amendment also specifies the accounting of some costs to obtain or fulfill a contract with a customer and expands the disclosure requirements around contracts with customers. An entity can either adopt this amendment retrospectively to each prior reporting period presented or retrospectively with the cumulative effect of initially applying the update recognized at the date of initial application. In July 2015, the FASB adopted a one-year deferral of this guidance. As a result, this guidance will be effective January 1, 2018 with the option to adopt the standard as of the original effective date, January 1, 2017. The Company is currently evaluating the impact of the adoption of ASU 2014-09 on the Company’s financial statements. In January 2015, the Company adopted the amended guidance of ASC Topic 205, Presentation of Financial Statements (Topic 205) and ASC Topic 360, Property, Plant, and Equipment, which limit the definition of discontinued operations as only those disposals of components of an entity that represent a strategic shift that has (or will have) a major effect on an entity’s operations and financial results. The amended guidance also expands the definition of discontinued operations to include a business or nonprofit activity that, on acquisition, meets the criteria to be classified as held for sale and a disposal of an equity method investment that meets the definition of discontinued operations. The amended guidance requires the Company to report discontinued operations if (1) the component of an entity or group of components of an entity meets the criteria in Topic 205 to be classified as held for sale; (2) the component of an entity or group of components of an entity is disposed of by sale; or (3) the component of an entity or group of components of an entity is disposed other than by sale. We considered this amended guidance and determined the sale of the North American utility pole business should not be reported as a discontinued operation. The Company does not believe the sale of this business to have a major effect on the Company’s operations and financial results.

Plant Closures and Divestitures

Plant Closures and Divestitures	6 Months Ended
	Jun. 30, 2015
Discontinued Operations and Disposal Groups [Abstract]
Plant Closures and Divestitures	3. Plant Closures and Divestitures On January 16, 2015, Koppers Inc. sold its North American utility pole business for cash of $12.3 million and a promissory note of $1.3 million. The Company recognized a gain of $3.2 million on this transaction. The promissory note is repayable in four equal annual installments beginning January 2016. This gain is reported in “Gain on sale of business” on the Consolidated Statement of Operations. The proceeds of the sale are reported within “Net cash proceeds from divestitures and asset sales” on the Condensed Consolidated Statement of Cash Flows. In March 2015, the Company announced its decision to discontinue production at its Railroad and Utility Products and Services plant located in Green Spring, West Virginia. Accordingly, the Company recorded a severance and fixed asset impairment charge of $2.7 million. As of June 30, 2015, the remaining net book value of fixed assets subject to impairment was $0.4 million. This amount will be reflected in depreciation expense on an accelerated basis reflecting management’s estimate of the remaining useful life of the assets. The closure is expected to be completed by September 2015. Details of the restructuring activities and related reserves for past closures of certain of the Company’s facilities in the Netherlands, Australia and the United States are as follows: Severance and Environmental Site Other Total (Dollars in millions) Reserve at December 31, 2013 $ 0.1 $ 5.6 $ 3.3 $ 0.0 $ 9.0 Accrual 9.8 0.0 3.2 0.1 13.1 Reversal of accrued charges 0.0 (1.1 ) (0.9 ) 0.0 (2.0 ) Cash paid (9.7 ) 0.0 (1.3 ) 0.0 (11.0 ) Currency translation (0.2 ) (0.4 ) (0.4 ) 0.0 (1.0 ) Reserve at December 31, 2014 $ 0.0 $ 4.1 $ 3.9 $ 0.1 $ 8.1 Accrual 0.3 0.0 0.0 0.0 0.3 Reversal of accrued charges 0.0 0.0 (0.3 ) (0.1 ) (0.4 ) Cash paid 0.0 0.0 (1.5 ) 0.0 (1.5 ) Currency translation 0.0 (0.2 ) (0.3 ) 0.0 (0.5 ) Reserve at June 30, 2015 $ 0.3 $ 3.9 $ 1.8 $ 0.0 $ 6.0

Business Acquisitions

Business Acquisitions	6 Months Ended
	Jun. 30, 2015
Business Combinations [Abstract]
Business Acquisitions	4. Business Acquisitions KMG Osmose Entities – Subsequent to the acquisition, Osmose, Inc. was renamed Koppers Performance Chemicals Inc. and Osmose Railroad Services, Inc. was renamed Koppers Railroad Structures Inc. Koppers Performance Chemicals Inc.’s wood preservation business develops, manufactures and sells wood preservation chemicals and wood treatment technologies for infrastructure, residential and commercial construction, and agricultural markets. The wood preservation business has operations and sales in North America, South America, Europe, and Australasia. Substantially all of the businesses of Koppers Performance Chemicals Inc. are reported as our Performance Chemicals segment. Koppers Railroad Structures Inc. is a provider of railroad infrastructure services, including bridge inspection, engineering, maintenance and repair, and construction services for the Class I and shortline railroads in North America. Koppers Railroad Structures Inc. and one wood treating company, which is a subsidiary of Koppers Performance Chemicals Inc., are reported as part of the Railroad and Utility Products and Services segment. The consolidated balance sheet as of December 31, 2014 reflected a preliminary fair value determination of the acquired assets and liabilities based on assumptions and estimates that, while considered reasonable under the circumstances, are subject to change. As of June 30, 2015, the Company has adjusted the value of certain acquired assets and liabilities which has resulted in a net increase to goodwill of approximately $9.2 million since December 31, 2014. The fair value determination of the acquired assets and liabilities is substantially complete and will be finalized in the third quarter of 2015. The following unaudited pro forma information presents a summary of the Company’s revenues and net income from continuing operations as if the acquisition occurred on January 1, 2014. 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, 2014 and does not intend to project the future financial results of the Company after the acquisition of the Osmose Entities. The unaudited pro forma information is based on certain assumptions, which management believes are reasonable, and do not reflect the cost of any integration activities or the benefits from the acquisition and synergies that may be derived from any integration activities. Three months Six months (Dollars in millions) Revenue $ 470.1 $ 892.8 Income from continuing operations attributable to Koppers 12.5 13.0 Pro forma adjustments reflected in the unaudited pro forma information are based on items that are directly attributable to the acquisition of the Osmose Entities and related financing that are factually supportable and are expected to have a continuing impact on Koppers. These adjustments include, but are not limited to, depreciation and amortization related to preliminary fair value adjustments to property, plant and equipment and intangible assets, interest expense on acquisition-related debt, removal of acquisition-related transaction expenses, the elimination of intercompany sales and related income tax effects of the pro forma adjustments.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	5. Fair Value Measurements Carrying amounts and the related estimated fair values of the Company’s financial instruments as of June 30, 2015 and December 31, 2014 are as follows: June 30, 2015 December 31, 2014 Fair Value Carrying Fair Value Carrying (Dollars in millions) Financial assets: Cash and cash equivalents, including restricted cash $ 51.2 $ 51.2 $ 51.1 $ 51.1 Investments and other assets (a) 1.4 1.4 1.5 1.5 Financial liabilities: Long-term debt (including current portion) $ 806.2 $ 794.2 $ 862.1 $ 850.5 (a) Excludes equity method investments. Cash and cash equivalents Investments and other assets – Debt

Comprehensive Income and Equity

Comprehensive Income and Equity	6 Months Ended
	Jun. 30, 2015
Equity [Abstract]
Comprehensive Income and Equity	6. Comprehensive Income and Equity Total comprehensive income for the three and six months ended June 30, 2015 and 2014 is summarized in the table below: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 (Dollars in millions) Net income $ 7.9 $ 0.7 $ 3.7 $ 0.6 Other comprehensive income (loss): Change in currency translation adjustment 2.4 0.9 (8.2 ) 0.7 Change in foreign currency transactions of long-term subsidiary investments 0.0 1.0 0.0 3.4 Change in derivative financial instrument net loss, net of tax benefit (expense) of $0.1, $0.0, $0.2 and $0.0 (0.2 ) 0.0 (0.5 ) 0.0 Change in unrecognized pension net income, net of tax benefit (expense) of $(0.4), $(0.2), $(0.8) and $(0.5) 1.0 0.6 2.0 1.2 Change in unrecognized prior service cost, net of tax benefit (expense) of $0.0, $0.0, $0.0 and $0.0 0.0 0.0 (0.1 ) (0.1 ) Total comprehensive income (loss) 11.1 3.2 (3.1 ) 5.8 Less: comprehensive loss attributable to noncontrolling interests (1.1 ) (0.9 ) (1.9 ) (3.6 ) Comprehensive income (loss) attributable to Koppers $ 12.2 $ 4.1 $ (1.2 ) $ 9.4 Amounts reclassified from accumulated other comprehensive income to net income consist of amounts shown for changes in unrecognized pension net loss, unrecognized prior service cost and unrecognized transition asset. These components of accumulated other comprehensive income are included in the computation of net periodic pension cost as disclosed in Note 13 – Pensions and Postretirement Benefit Plans. Other amounts reclassified from accumulated other comprehensive income include losses related to derivative financial instruments of $1.0 million and $1.9 million for the three and six months ended June 30, 2015, respectively. The following tables present the change in equity for the six months ended June 30, 2015 and 2014, respectively: (Dollars in millions) Total Koppers Equity Noncontrolling Total Equity Balance at December 31, 2014 $ 70.0 $ 13.9 $ 83.9 Net income (loss) 5.6 (1.9 ) 3.7 Employee stock plans 2.0 0.0 2.0 Other comprehensive (loss) income (6.9 ) 0.0 (6.9 ) Dividends 0.0 (3.5 ) (3.5 ) Repurchases of common stock (0.3 ) 0.0 (0.3 ) Balance at June 30, 2015 $ 70.4 $ 8.5 $ 78.9 (Dollars in millions) Total Koppers Equity Noncontrolling Total Equity Balance at December 31, 2013 $ 169.8 $ 20.0 $ 189.8 Net income (loss) 3.8 (3.2 ) 0.6 Issuance of common stock 0.7 0.0 0.7 Employee stock plans 3.4 0.0 3.4 Other comprehensive income (loss) 5.6 (0.5 ) 5.1 Dividends (10.4 ) 0.0 (10.4 ) Investment in noncontrolling interests 0.0 1.4 1.4 Repurchases of common stock (2.0 ) 0.0 (2.0 ) Balance at June 30, 2014 $ 170.9 $ 17.7 $ 188.6

Earnings per Common Share

Earnings per Common Share	6 Months Ended
	Jun. 30, 2015
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 earnings per common share. The following table sets forth the computation of basic and diluted earnings per common share: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 (Dollars in millions, except share amounts, in thousands, and per share amounts) Net income attributable to Koppers $ 9.0 $ 1.6 $ 5.6 $ 3.8 Less: loss from discontinued operations 0.0 (0.1 ) 0.0 (0.1 ) Income from continuing operations attributable to Koppers $ 9.0 $ 1.7 $ 5.6 $ 3.9 Weighted average common shares outstanding: Basic 20,545 20,475 20,529 20,430 Effect of dilutive securities 95 107 74 154 Diluted 20,640 20,582 20,603 20,584 Earnings per common share – continuing operations: Basic earnings per common share $ 0.44 $ 0.08 $ 0.28 $ 0.19 Diluted earnings per common share 0.44 0.08 0.27 0.19 Other data: Antidilutive securities excluded from computation of diluted earnings per common share 442 284 644 258

Stock-based Compensation

Stock-based Compensation	6 Months Ended
	Jun. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based Compensation	8. Stock-based Compensation The amended and restated 2005 Long-Term Incentive Plan (the “LTIP”) provides for the grant to eligible persons of stock options, stock appreciation rights, restricted stock, restricted stock units, performance shares, performance awards, dividend equivalents and other stock-based awards, which are collectively referred to as the awards. Under the LTIP, the board of directors granted restricted stock units and performance stock units to certain employee participants (collectively, the “stock units”). For grants prior to 2015, restricted stock units vest on the third anniversary of the grant date, assuming continued employment by the participant. For the March 2015 grant, the restricted stock units vest in four equal annual installments. Performance stock units granted generally have three-year performance objectives and all performance stock units have a three-year period for vesting (if the applicable performance objective is obtained). The applicable performance objective is based upon a multi-year cumulative value creation calculation that considers the Company’s financial performance commencing on the first day of each grant year. The number of performance stock units granted represents the target award and participants have the ability to earn between zero and 150 percent or 200 percent (depending on the grant date) of the target award based upon actual performance. If minimum performance criteria are not achieved, no performance stock units will vest. Dividends declared on the Company’s common stock during the period prior to vesting of the stock units are credited at equivalent value as additional stock units and become payable as additional common shares upon vesting. In the event of termination of employment, other than retirement, death or disability, any non-vested stock units are forfeited, including additional stock units credited from dividends. In the event of termination of employment due to retirement, death or disability, pro-rata vesting of the stock units over the service period will result. There are special vesting provisions for the stock units related to a change in control. Restricted stock units that vest immediately or have one-year vesting periods are also issued under the LTIP to members of the board of directors in connection with annual director compensation and, from time to time, are issued to members of management in connection with employee compensation. 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 stock units is the market price of the underlying common stock on the date of grant. The following table shows a summary of the performance stock units as of June 30, 2015: Performance Period Minimum Target Maximum 2013 – 2015 0 80,578 120,867 2014 – 2016 0 94,341 141,512 2015 – 2017 0 223,684 447,368 The following table shows a summary of the status and activity of non-vested stock awards for the six months ended June 30, 2015: Restricted Stock Units Performance Stock Units Total Stock Units Weighted Average Non-vested at December 31, 2014 148,906 280,381 429,287 $ 39.31 Granted 141,775 223,684 365,459 $ 18.20 Credited from dividends 4,271 5,970 10,241 $ 37.78 Vested (62,929 ) 0 (62,929 ) $ 38.08 Forfeited (10,566 ) (106,031 ) (116,597 ) $ 38.49 Non-vested at June 30, 2015 221,457 404,004 625,461 $ 27.23 Prior to 2015, stock options to most executive officers vest and become exercisable upon the completion of a three-year service period commencing on the grant date. For the March 2015 grant, the stock options vest in four equal annual installments. The stock options have a term of 10 years. In the event of termination of employment, other than retirement, death or disability, any non-vested In accordance with accounting standards, compensation expense for non-vested stock options is recorded over the vesting period based on the fair value at the date of grant. The fair value of stock options on the date of grant is calculated using the Black-Scholes-Merton model and the assumptions listed below: March 2015 Grant February 2014 Grant February 2013 Grant Grant date price per share of stock option award $ 17.57 $ 37.93 $ 42.76 Expected dividend yield per share 3.40 % 2.75 % 2.75 % Expected life in years 5.75 6.5 6.5 Expected volatility 42.27 % 52.14 % 53.77 % Risk-free interest rate 1.73 % 1.98 % 1.29 % Grant date fair value per share of option awards $ 5.20 $ 15.26 $ 17.28 The dividend yield is based on the Company’s current and prospective dividend rate which calculates a continuous dividend yield based upon the market price of the underlying common stock. The expected life in years for the March 2015 grant is based on historical exercise data of options previously granted by the Company. The expected life in years for grants prior to 2015 are based on the simplified method permitted under Securities and Exchange Commission Staff Accounting Bulletin No. 14d.2 which calculates the average of the weighted vesting term and the contractual term of the option. This method was selected due to the lack of historical exercise data with respect to the Company at the time of those grants. Expected volatility is based on the historical volatility of the Company’s common stock and the historical volatility of certain other similar public companies. The risk-free interest rate is based on U.S. Treasury bill rates for the expected life of the option. The following table shows a summary of the status and activity of stock options for the six months ended June 30, 2015: Options Weighted Average per Option Weighted Average (in years) Aggregate Intrinsic Outstanding at December 31, 2014 448,812 $ 36.58 Granted 330,159 $ 17.57 Forfeited (4,722 ) $ 39.23 Outstanding at June 30, 2015 774,249 $ 28.46 7.24 $ 2.6 Exercisable at June 30, 2015 333,697 $ 35.36 4.42 $ 0.2 Total stock-based compensation expense recognized for the three and six months ended June 30, 2015 and 2014 is as follows: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 (Dollars in millions) Stock-based compensation expense recognized: Selling, general and administrative expenses $ 1.3 $ 2.0 $ 2.0 $ 3.2 Less related income tax benefit 0.5 0.8 0.8 1.3 $ 0.8 $ 1.2 $ 1.2 $ 1.9 As of June 30, 2015, total future gross compensation expense related to non-vested stock-based compensation arrangements, which are expected to vest, totaled $8.9 million and the weighted-average period over which this cost is expected to be recognized is approximately 31 months.

Segment Information

Segment Information	6 Months Ended
	Jun. 30, 2015
Segment Reporting [Abstract]
Segment Information	9. Segment Information The Company has three reportable segments: Carbon Materials and Chemicals, Railroad and Utility Products and Services, and Performance Chemicals. The Company’s reportable segments contain business units that are aggregated since management believes the long-term financial performance of these business units is affected by similar economic conditions. The reportable segments are each managed separately because they manufacture and distribute distinct products with different production processes. The Company’s Carbon Materials and Chemicals segment is primarily a manufacturer of carbon pitch, naphthalene, phthalic anhydride, creosote and carbon black feedstock. 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. Creosote is used in the treatment of wood and carbon black feedstock is used in the production of carbon black. The Company’s Railroad and Utility Products and Services segment sells treated and untreated wood products, manufactured products and services primarily to the railroad and public utility markets. Railroad products include procuring and treating items such as crossties, switch ties and various types of lumber used for railroad bridges and crossings and the manufacture of rail joint bars. Utility products include transmission and distribution poles and pilings. The Company’s Performance Chemicals segment develops, manufactures, and markets wood preservation chemicals and wood treatment technologies and services a diverse range of end-markets including infrastructure, residential and commercial construction, and agriculture. The Company evaluates performance and determines resource allocations based on a number of factors, the primary measure being operating profit or loss from operations. Operating profit does not include equity in earnings of affiliates, other income, interest expense or income taxes. Operating profit also excludes the operating costs of Koppers Holdings Inc., the parent company of Koppers Inc. The accounting policies of the reportable segments are the same as those described in the summary of significant accounting policies. Intersegment transactions are eliminated in consolidation. The following table sets forth certain sales and operating data, net of all intersegment transactions, for the Company’s segments for the periods indicated: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 (Dollars in millions) Revenues from external customers: Carbon Materials and Chemicals $ 158.4 $ 208.6 $ 316.6 $ 411.2 Railroad and Utility Products and Services 170.9 148.2 329.0 277.0 Performance Chemicals 102.3 0.0 183.8 0.0 Total $ 431.6 $ 356.8 $ 829.4 $ 688.2 Intersegment revenues: Carbon Materials and Chemicals $ 20.0 $ 20.1 $ 40.5 $ 41.3 Performance Chemicals 2.2 0.0 4.3 0.0 Total $ 22.2 $ 20.1 $ 44.8 $ 41.3 Depreciation and amortization expense: Carbon Materials and Chemicals (a) $ 6.5 $ 6.0 $ 12.7 $ 12.1 Railroad and Utility Products and Services (b) 6.4 3.7 10.5 6.5 Performance Chemicals 4.8 0.0 9.5 0.0 Total $ 17.7 $ 9.7 $ 32.7 $ 18.6 Operating profit (loss): Carbon Materials and Chemicals (c) $ (2.9 ) $ 3.8 $ (13.8 ) $ (5.0 ) Railroad and Utility Products and Services (d) 15.0 12.8 30.4 23.9 Performance Chemicals 15.5 0.0 21.9 0.0 Corporate (e) (1.6 ) (3.3 ) (4.5 ) (5.1 ) Total $ 26.0 $ 13.3 $ 34.0 $ 13.8 (a) Excludes impairment charges of $4.7 million for the six months ended June 30, 2014 for the Tangshan, China facility. (b) Excludes impairment charges of $2.5 million for the six months ended June 30, 2015 for a wood treating facility in the United States. (c) Includes plant closure costs of $10.8 million for the six months ended June 30, 2014 for the Uithoorn, the Netherlands facility and impairment charges of $4.7 million for the six months ended June 30, 2014 for the Tangshan, China facility. (d) Includes gain on sale of the Company’s North American utility pole business of $3.2 million and impairment charges of $2.5 million for a wood treating facility in the United States in the six months ended June 30, 2015. (e) Operating loss for Corporate includes general and administrative costs for Koppers Holdings Inc., the parent company of Koppers Inc., and foreign exchange revaluation related to intercompany loans in connection with a legal reorganization of the Company. The following table sets forth certain tangible and intangible assets allocated to each of the Company’s segments as of the dates indicated: June 30, 2015 December 31, 2014 (Dollars in millions) Segment assets: Carbon Materials and Chemicals $ 505.0 $ 514.6 Railroad and Utility Products and Services 267.7 275.2 Performance Chemicals 479.3 469.0 All other 38.1 35.1 Total $ 1,290.1 $ 1,293.9 Goodwill: Carbon Materials and Chemicals $ 68.3 $ 65.5 Railroad and Utility Products and Services 10.3 9.3 Performance Chemicals 178.0 172.4 Total $ 256.6 $ 247.2

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2015
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes Effective Tax Rate The income tax provision for interim periods is based on an estimated annual effective tax rate, which requires management to make its best estimate of annual pretax income by domestic and foreign jurisdictions and other items that impact taxable income. Items that are not related to annual pretax ordinary income are recognized entirely in the interim period as a discrete item. Such items include the results of certain entities that have historical pre-tax losses and current year estimated pre-tax losses that are not projected to be utilized. Income taxes as a percentage of pretax ordinary income were 30.8 percent and 65.0 percent for each of the three months ended on June 30, 2015 and 2014, respectively. Discrete items included in income taxes for the three months ended on June 30, 2015 and June 30, 2014, respectively, were not material. The effective tax rate for the three months ended on June 30, 2015 differs from the U.S. federal statutory rate of 35.0 percent due to the taxes on foreign earnings (-7.3 percent) partially offset by nondeductible expenses (+1.1 percent), uncertain tax positions (+1.0 percent), and state taxes (+1.0 percent). With respect to the three months ended on June 30, 2014, the effective tax rate differs from the U.S. federal statutory rate of 35.0 percent due to taxes on foreign earnings (+28.2 percent), state taxes (+2.0 percent), uncertain tax positions (+1.2 percent) and nondeductible expenses (+1.0 percent) partially offset by the domestic manufacturing deduction (-2.4 percent). Income taxes as a percentage of pretax ordinary income before discrete items were 30.8 percent and 64.3 percent for the six months ended on June 30, 2015 and 2014, respectively. Discrete items included in income taxes for the six months ended on June 30, 2015 were a net tax benefit of $0.3 million which was primarily related to the closure of an IRS audit of the Company’s US tax returns through 2011. Discrete items included in income taxes for the six months ended on June 30, 2014 were a net tax benefit of $5.7 million which was primarily related to management’s decision that a deferred tax liability for certain undistributed earnings of its European subsidiaries was no longer necessary as these earnings are permanently reinvested. The effective tax rate for the six months ended on June 30, 2015 differs from the U.S. federal statutory rate of 35.0 percent due to the taxes on foreign earnings (-7.4 percent) partially offset by nondeductible expenses (+1.1 percent), state taxes (+1.1 percent), and uncertain tax positions (+1.0 percent). With respect to the six months ended on June 30 2014, the effective tax rate differs from the U.S. federal statutory rate of 35.0 percent primarily due to the taxes on foreign earnings (+27.6 percent), state taxes (+1.8 percent), uncertain tax positions (+1.2 percent) and nondeductible expenses (+1.0 percent) partially offset by the domestic manufacturing deduction (-2.3 percent). During the year, management regularly updates estimates based on changes in various factors such as product prices, shipments, product mix, operating and administrative costs, earnings mix by taxable jurisdiction, repatriation of foreign earnings, uncertain tax positions and the ability to claim tax credits. To the extent that actual results vary from the estimates at the end of the second quarter, the actual tax provision recognized for 2015 could be materially different from the forecasted annual tax provision as of the end of the second quarter. Uncertain Tax Positions The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction, individual U.S. state jurisdictions and non-U.S. jurisdictions. With few exceptions, the Company is no longer subject to U.S. federal, state and local, or non-U.S. income tax examinations by tax authorities for years before 2010. As of June 30, 2015 and December 31, 2014, the total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate, was approximately $5.5 million and $6.0 million, respectively. Unrecognized tax benefits totaled $6.9 million and $7.2 million as of June 30, 2015 and December 31, 2014, respectively. The Company recognizes interest expense and any related penalties from uncertain tax positions in income tax expense. As of June 30, 2015 and December 31, 2014 the Company had accrued approximately $2.7 million and $2.7 million for interest and penalties, respectively.

Inventories

Inventories	6 Months Ended
	Jun. 30, 2015
Inventory Disclosure [Abstract]
Inventories	11. Inventories Net inventories as of June 30, 2015 and December 31, 2014 are summarized in the table below: June 30, 2015 December 31, 2014 (Dollars in millions) Raw materials $ 166.6 $ 191.1 Work in process 16.1 2.6 Finished goods 98.2 103.6 280.9 297.3 Less revaluation to LIFO 57.5 56.1 Net $ 223.4 $ 241.2

Property, Plant and Equipment

Property, Plant and Equipment	6 Months Ended
	Jun. 30, 2015
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	12. Property, Plant and Equipment Property, plant and equipment as of June 30, 2015 and December 31, 2014 are summarized in the table below: June 30, 2015 December 31, 2014 (Dollars in millions) Land $ 18.1 $ 18.7 Buildings 41.7 45.3 Machinery and equipment 698.7 678.6 758.5 742.6 Less accumulated depreciation 466.6 442.9 Net $ 291.9 $ 299.7 Impairments The 2014 impairment of the Company’s coal tar distillation plant in Tangshan, China was due to the impending forced closure of a neighboring third party owned metallurgical coke facility. The adjacent coke battery is expected to cease production sometime within the next eight to twelve months. The Company’s 60-percent owned subsidiary, Koppers (China) Carbon & Chemical Company Limited (“KCCC”) is located near the coke facility and relies on its operations for a significant portion of raw material supply, utilities and other shared services. Closure of the coke batteries directly impacts KCCC’s ability to operate its coal tar distillation plant and the Company has determined that it is unable to continue coal tar distillation activities at the site once the neighboring coke battery ceases production activities. As of June 30, 2015, all fixed assets directly related to the facility have been substantially depreciated.

Pensions and Postretirement Ben

Pensions and Postretirement Benefit Plans	6 Months Ended
	Jun. 30, 2015
Compensation and Retirement Disclosure [Abstract]
Pensions and Postretirement Benefit Plans	13. Pensions and Postretirement Benefit Plans The Company and its subsidiaries maintain a number of defined benefit and defined contribution plans to provide retirement benefits for employees in the U.S., as well as employees outside the U.S. These plans are maintained and contributions are made in accordance with the Employee Retirement Income Security Act of 1974 (“ERISA”), local statutory law or as determined by the board of directors. The defined benefit pension plans generally provide benefits based upon years of service and compensation. Pension plans are funded except for three domestic non-qualified defined benefit pension plans for certain key executives. In the U.S., all qualified defined benefit pension plans for salaried employees have been closed to new participants and a number of plans, including most plans for hourly employees, have been frozen or are scheduled to be frozen in the next year. Accordingly, these pension plans no longer accrue additional years of service or recognize future increases in compensation for benefit purposes. The defined contribution plans generally provide retirement assets to employee participants based upon employer and employee contributions to the participant’s individual investment account. The Company also provides retiree medical insurance coverage to certain U.S. employees and a life insurance benefit to most U.S. employees. For salaried employees, the retiree medical and retiree insurance plans have been closed to new participants. The following table provides the components of net periodic benefit cost for the pension plans and other benefit plans for the three and six months ended June 30, 2015 and 2014: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 (Dollars in millions) Service cost $ 0.5 $ 0.6 $ 1.0 $ 1.2 Interest cost 2.6 3.1 5.4 6.0 Expected return on plan assets (3.0 ) (3.5 ) (6.0 ) (7.0 ) Amortization of prior service cost 0.0 (0.1 ) (0.1 ) (0.1 ) Amortization of net loss 1.7 1.0 3.3 2.0 Net periodic benefit cost $ 1.8 $ 1.1 $ 3.6 $ 2.1 Defined contribution plan expense (a) $ 2.0 $ 1.5 $ 2.0 $ 3.2 (a) The six months ended June 30, 2015 includes reversal of 2014 discretionary 401k match accrual of $2.2 million.

Debt

Debt	6 Months Ended
	Jun. 30, 2015
Debt Disclosure [Abstract]
Debt	14. Debt Debt at June 30, 2015 and December 31, 2014 was as follows: Weighted Maturity June 30, 2015 December 31, 2014 (Dollars in millions) Term Loan 3 3 / 4 % 2019 $ 277.5 $ 292.5 Revolving Credit Facility 3 3 / 4 % 2019 161.3 204.5 Construction and other loans 5.81% 2018 58.1 56.5 Senior Notes 7 7 / 8 % 2019 297.3 297.0 Total debt 794.2 850.5 Less short term debt and current maturities of long-term debt 45.4 43.9 Long-term debt $ 748.8 $ 806.6 Revolving Credit Facility On August 15, 2014, Koppers Inc. replaced its $350.0 million revolving credit facility with a new $500.0 million senior secured revolving credit facility and a $300.0 million senior secured term loan to finance its acquisition of the Osmose Entities (the “Senior Secured Credit Facilities”). Both borrowings mature on August 15, 2019. The interest rates on the new borrowings are variable and are based on LIBOR. The initial interest rate on the borrowings at August 15, 2014 was 3.25 percent. The senior secured term loan has quarterly principal repayment obligations of 2.5 percent of the original principal amount borrowed, or $7.5 million. Borrowings under the revolving credit facility and term loan are secured by a first priority lien on substantially all of the assets of Koppers Inc. and its material domestic subsidiaries. The revolving credit facility and term loan contain 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. The Company entered into an amendment of the revolving credit facility dated June 30, 2015 which excludes dividends paid by Koppers Holdings Inc. from the calculation of fixed charges under the fixed charge coverage ratio. Koppers Holdings last paid a dividend in January 2015. In the event that Koppers Holdings pays any dividends subsequent to June 30, 2015, all dividends paid by Koppers Holdings during any period of determination will be included in the calculation of fixed charges under the fixed charge coverage ratio. The Company would have been in compliance with all covenants at June 30, 2015 regardless of this amendment, and accordingly, the amendment has been accounted for as a modification. As of June 30, 2015, the Company had $80.2 million of unused revolving credit availability for working capital purposes after restrictions from certain letter of credit commitments and other covenants. As of June 30, 2015, $61.6 million of commitments were utilized by outstanding letters of credit. Construction Loans On November 18, 2013, the Company’s 75-percent owned subsidiary, Koppers (Jiangsu) Carbon Chemical Company Limited (“KJCC”) entered into two committed loan facility agreements for a combined commitment of RMB 265 million or approximately $44 million. The third party bank provided facility has a commitment amount of RMB 198.8 million and the other committed facility of RMB 66.2 million is provided by the 25-percent non-controlling shareholder in KJCC. Borrowings under the third party bank facility are secured by a letter of credit issued by a bank under Koppers Inc. revolving credit facility. The committed facilities were used to finance the costs related to the construction of the coal tar distillation plant in Pizhou, Jiangsu province in China. The facilities are variable rate and have certain financial covenants that monitor minimum net worth and leverage. KJCC will repay the loans in six installments every six months starting in May 2016 with a final repayment on November 18, 2018, the maturity date of the loans. Senior Notes The Koppers Inc. 7 7 / 8 percent Senior Notes due 2019 (the “Senior Notes”) were issued on December 1, 2009 at an offering price of 98.311 percent of face value, or $294.9 million and have a principal amount at maturity of $300.0 million. The Senior Notes have an effective interest rate yield of 8 1 / 8 percent per annum. The Senior Notes are our senior obligations, are fully and unconditionally guaranteed by Koppers Holdings Inc. and certain of our wholly-owned domestic subsidiaries, and, as of August 15, 2014, are secured equally and ratably with the obligations under our Senior Secured Credit Facilities. Interest on the Senior Notes is payable semiannually on December 1 and June 1 each year. On or after December 1, 2014, the Company is entitled to redeem all or a portion of the Senior Notes at a redemption price of 103.938 percent of principal value, declining annually in ratable amounts until the redemption price is equivalent to the principal value on December 1, 2017. The indenture governing the 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.

Asset Retirement Obligations

Asset Retirement Obligations	6 Months Ended
	Jun. 30, 2015
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	15. Asset Retirement Obligations The Company recognizes asset retirement obligations for the removal and disposal of residues; dismantling of certain tanks required by governmental authorities; cleaning and dismantling costs for owned rail cars; and cleaning costs for leased rail cars and barges. The following table reflects changes in the carrying values of asset retirement obligations: June 30, December 31, (Dollars in millions) Asset retirement obligation at beginning of year $ 30.5 $ 23.2 Acquisition 0.8 0.0 Accretion expense 1.5 2.3 Revision in estimated cash flows 3.3 10.3 Cash expenditures (3.5 ) (4.6 ) Currency translation (0.4 ) (0.7 ) Balance at end of period $ 32.2 $ 30.5

Deferred Revenue

Deferred Revenue	6 Months Ended
	Jun. 30, 2015
Deferred Revenue Disclosure [Abstract]
Deferred Revenue	16. Deferred Revenue The Company defers revenues associated with extended product warranty liabilities based on historical loss experience and sales of extended warranties on certain products. In addition, the Company received an advance payment in 2015 related to an amendment to a 50-year supply agreement with a customer in China. The deferred revenue associated with this amendment will be amortized over the life of the underlying contract. The following table reflects changes in the carrying values of deferred revenue: June 30, December 31, (Dollars in millions) Balance at beginning of year $ 2.5 $ 3.2 Advance payment 29.6 0.0 Revenue earned (0.2 ) (0.7 ) Balance at end of period $ 31.9 $ 2.5 Deferred revenue classified in other long-term liabilities in the consolidated balance sheet totaled $30.7 million as of June 30, 2015.

Derivative Financial Instrument

Derivative Financial Instruments	6 Months Ended
	Jun. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	17. Derivative Financial Instruments The Company utilizes derivative instruments to manage exposures to risks that have been identified and measured and are capable of being controlled. The primary risks managed by the company by using derivative instruments are commodity price risk associated with copper and foreign currency exchange risk associated with a number of currencies, principally the U.S. dollar, the Canadian dollar, the New Zealand dollar, the Euro and British pounds. Swap contracts on copper are used to manage the price risk associated with forecasted purchases of materials used in the Company’s manufacturing processes. Generally, the Company will not hedge cash flow exposures for durations longer than 30 months. The Company enters into foreign currency forward contracts to manage foreign currency risk associated with the Company’s receivable and payable balances. Generally, the Company enters into master netting arrangements with the counterparties and offsets net derivative positions with the same counterparties. Currently, the Company’s agreements do not require cash collateral. ASC Topic 815-10, “Derivatives and Hedging,” requires companies to recognize all derivative instruments as either assets or liabilities at fair value in the balance sheet. Derivative instruments’ fair value is determined using significant other observable inputs, or Level 2 in the fair value hierarchy. In accordance with ASC Topic 815-10, the Company designates commodity swaps as cash flow hedges of forecasted purchases of commodities. For derivative instruments that are designated and qualify as cash flow hedges, the effective portion of the gain or loss on the derivative is reported as a component of other comprehensive (loss) income and is reclassified into earnings in the same period or periods during which the hedged transaction affects earnings. Gains and losses on the derivative instruments representing either hedge ineffectiveness or hedge components excluded from the assessment of effectiveness are recognized in current earnings. The amount of hedge ineffectiveness charged to profit and loss is not material for any period presented. As of June 30, 2015, the Company has outstanding copper swap contracts totaling 18.2 million pounds and the fair value of these swap contracts was $(7.2) million which is classified in accrued liabilities in the consolidated balance sheet. The amount of loss recognized in other comprehensive loss totaled $4.3 million, net of tax, at June 30, 2015. In the next twelve months the Company estimates that $3.3 million of unrealized losses, net of tax, related to commodity price hedging will be reclassified from other comprehensive loss into earnings. Forward contracts related to foreign currency are not designated as hedges and fair value changes in these contracts are immediately charged to earnings and are classified in cost of sales in the condensed consolidated statement of income. As of June 30, 2015, the Company has outstanding foreign currency forward contracts with a net fair value totaling $1.3 million, consisting of a gross derivative asset of $3.5 million and a gross derivative liability of $2.2 million. The currency units outstanding at June 30, 2015 were British Pound of GBP 42.4 million, New Zealand Dollar of NZD 40.1 million, Canadian Dollar of CAD 15.8 million and United States Dollar of USD 88.1 million.

Commitments and Contingent Liab

Commitments and Contingent Liabilities	6 Months Ended
	Jun. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	18. Commitments and Contingent Liabilities The Company and its subsidiaries are involved in litigation and various proceedings relating to environmental laws and regulations and toxic tort, product liability and other matters. Certain of these matters are discussed below. The ultimate resolution of these contingencies is subject to significant uncertainty and should the Company or its subsidiaries fail to prevail in any of these legal matters or should several of these legal matters be resolved against the Company or its subsidiaries in the same reporting period, these legal matters could, individually or in the aggregate, be material to the consolidated financial statements. Legal Proceedings Coal Tar Pitch Cases . The plaintiffs in all 60 pending cases seek to recover compensatory damages, while plaintiffs in 55 cases also seek to recover punitive damages. The plaintiffs in the 59 cases filed in Pennsylvania state court seek unspecified damages in excess of the court’s minimum jurisdictional limit. The plaintiffs in the Tennessee state court case each seek damages of $15.0 million. The other defendants in these lawsuits vary from case to case and include companies such as Beazer East, Inc., United States Steel Corporation, Honeywell International Inc., Vertellus Specialties Inc., Dow Chemical Company, UCAR Carbon Company, Inc., Exxon Mobil Corporation, SGL Carbon Corporation and Alcoa, Inc. Discovery is proceeding in these cases. No trial dates have been set in any of these cases. The Company has not provided a reserve for these lawsuits because, at this time, the Company cannot reasonably determine the probability of a loss, and the amount of loss, if any, cannot be reasonably estimated. The timing of resolution of these cases cannot be reasonably determined. Although Koppers Inc. is vigorously defending these cases, an unfavorable resolution of these matters may have a material adverse effect on the Company’s business, financial condition, cash flows and results of operations. Gainesville . In November 2010, a class action complaint was filed in the Circuit Court of the Eighth Judicial Circuit located in Alachua County, Florida by residential real property owners located in a neighborhood west of and immediately adjacent to the former utility pole treatment plant in Gainesville. The complaint named Koppers Holdings Inc., Koppers Inc., Beazer East and several other parties as defendants. In a second amended complaint, plaintiffs define the putative class as consisting of all persons who are present record owners of residential real properties located in an area within a two-mile radius of the former Gainesville wood treating plant. Plaintiffs further allege that chemicals and contaminants from the Gainesville plant have contaminated real properties within the two mile geographical area, have caused property damage (diminution in value) and have placed residents and owners of the putative class properties at an elevated risk of exposure to and injury from the chemicals at issue. The second amended complaint seeks damages for diminution in property values, the establishment of a medical monitoring fund and punitive damages. The case was removed to the United States District Court for the Northern District of Florida in December 2010. The district court dismissed Koppers Holdings Inc. in September 2013 on the ground that there was no personal jurisdiction. Plaintiffs’ appeal of the dismissal of Koppers Holdings Inc. was dismissed in December 2013. Under the current scheduling order, class factual discovery closed on May 20, 2015, with expert witness discovery to follow. Discovery on the merits is stayed until further order of the court. The Company has not provided a reserve for this matter because, at this time, it cannot reasonably determine the probability of a loss, and the amount of loss, if any, cannot be reasonably estimated. The timing of resolution of this case cannot be reasonably determined. Although the Company is vigorously defending this case, an unfavorable resolution of this matter may have a material adverse effect on the Company’s business, financial condition, cash flows and results of operations. Virgin Islands Environmental and Other Litigation Matters The Company and its subsidiaries are subject to federal, state, local and foreign laws and regulations and potential liabilities relating to the protection of the environment and human health and safety including, among other things, the cleanup of contaminated sites, the treatment, storage and disposal of wastes, the discharge of effluent into waterways, the emission of substances into the air and various health and safety matters. The Company’s subsidiaries expect to incur substantial costs for ongoing compliance with such laws and regulations. The Company’s subsidiaries may also face governmental or third-party claims, or otherwise incur costs, relating to cleanup of, or for injuries resulting from, contamination at sites associated with past and present operations. The Company accrues for environmental liabilities when a determination can be made that a liability is probable and reasonably estimable. Environmental and Other Liabilities Retained or Assumed by Others. The Indemnity provides different mechanisms, subject to certain limitations, by which Beazer East is obligated to indemnify Koppers Inc. with regard to certain environmental, product and other liabilities and imposes certain conditions on Koppers Inc. before receiving such indemnification, including, in some cases, certain limitations regarding the time period as to which claims for indemnification can be brought. In July 2004, Koppers Inc. and Beazer East agreed to amend the environmental indemnification provisions of the December 29, 1988 asset purchase agreement to extend the indemnification period for pre-closing environmental liabilities through July 2019. As consideration for the amendment, Koppers Inc. paid Beazer East a total of $7.0 million and agreed to share toxic tort litigation defense costs arising from any sites acquired from Beazer East. The July 2004 amendment did not change the provisions of the Indemnity with respect to indemnification for non-environmental claims, such as product liability claims, which claims may continue to be asserted after July 2019. Qualified expenditures under the Indemnity are not subject to a monetary limit. Qualified expenditures under the Indemnity include (i) environmental cleanup liabilities required by third parties, such as investigation, remediation and closure costs, relating to pre-December 29, 1988 or (“Pre-Closing”) acts or omissions of Beazer East or its predecessors; (ii) environmental claims by third parties for personal injuries, property damages and natural resources damages relating to Pre-Closing acts or omissions of Beazer East or its predecessors; (iii) punitive damages for the acts or omissions of Beazer East and its predecessors without regard to the date of the alleged conduct and (iv) product liability claims for products sold by Beazer East or its predecessors without regard to the date of the alleged conduct. If the third party claims described in sections (i) and (ii) above are not made by July 2019, Beazer East will not be required to pay the costs arising from such claims under the Indemnity. However, with respect to any such claims which are made by July 2019, Beazer East will continue to be responsible for such claims under the Indemnity beyond July 2019. The Indemnity provides for the resolution of issues between Koppers Inc. and Beazer East by an arbitrator on an expedited basis upon the request of either party. The arbitrator could be asked, among other things, to make a determination regarding the allocation of environmental responsibilities between Koppers Inc. and Beazer East. Arbitration decisions under the Indemnity are final and binding on the parties. Contamination has been identified at most manufacturing and other sites of the Company’s subsidiaries. One site currently owned and operated by Koppers Inc. in the United States is listed on the National Priorities List promulgated under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, as amended (“CERCLA”). Currently, at the properties acquired from Beazer East (which includes the National Priorities List site and all but one of the sites permitted under the Resource Conservation and Recovery Act (“RCRA”)), a significant portion of all investigative, cleanup and closure activities are being conducted and paid for by Beazer East pursuant to the terms of the Indemnity. In addition, other of Koppers Inc.’s sites are or have been operated under RCRA and various other environmental permits, and remedial and closure activities are being conducted at some of these sites. To date, the parties that retained, assumed and/or agreed to indemnify the Company against the liabilities referred to above, including Beazer East, have performed their obligations in all material respects. The Company believes that, for the last three years ended December 31, 2014, amounts paid by Beazer East as a result of its environmental remediation obligations under the Indemnity have averaged in total approximately $13 million per year. Periodically, issues have arisen between Koppers Inc. and Beazer East and/or other indemnitors that have been resolved without arbitration. Koppers Inc. and Beazer East engage in discussions from time to time that involve, among other things, the allocation of environmental costs related to certain operating and closed facilities. If for any reason (including disputed coverage or financial incapability) one or more of such parties fail to perform their obligations and the Company or its subsidiaries are held liable for or otherwise required to pay all or part of such liabilities without reimbursement, the imposition of such liabilities on the Company or its subsidiaries could have a material adverse effect on its business, financial condition, cash flows and results of operations. Furthermore, the Company could be required to record a contingent liability on its balance sheet with respect to such matters, which could result in a negative impact to the Company’s business, financial condition, cash flows and results of operations. Domestic Environmental Matters. de minimus In March 2012, a draft Feasibility Study (“FS”) was submitted to EPA by the Lower Willamette Group, a group of certain PRPs which has been conducting the investigation of the site. The draft FS identifies ten possible remedial alternatives which range in cost from approximately $170 million to $1.8 billion. The FS does not determine who is responsible for remediation costs or select remedies. The FS is under review by the EPA which will issue a final decision on the nature and extent of the final remediation. Responsibility for implementing and funding that work will be decided in the separate allocation process. In September 2009, Koppers Inc. received a general notice letter notifying it that it may be a PRP at the Newark Bay CERCLA site. In January 2010, Koppers Inc. submitted a response to the general notice letter asserting that Koppers Inc. is a de minimus Other than the estimated costs of participating in the PRP group at the Portland Harbor and Newark Bay CERCLA sites totaling $0.6 million at June 30, 2015, the Company has not provided a reserve for these matters because there has not been a determination of the total cost of the investigations, the remediation that will be required, the amount of natural resources damages or how those costs will be allocated among the PRPs. Accordingly, the Company believes that it cannot reasonably determine the probability of a loss, and the amount of loss, if any, cannot be reasonably estimated. An unfavorable resolution of these matters may have a material adverse effect on the Company’s business, financial condition, cash flows and results of operations. In connection with Koppers Inc.’s acquisition of the Osmose Entities, there are two plant sites in the United States where the Company has recorded an environmental remediation liability for soil and groundwater contamination which occurred prior to the acquisition. Osmose Holdings, Inc. has provided an indemnity of up to $5 million for certain environmental response costs incurred prior to August 15, 2017 (the “Osmose Indemnity”). As of June 30, 2015, the Company’s estimated environmental remediation liability for these acquired sites totals $5.8 million. The Company has also recorded a receivable under the Osmose Indemnity of $0.3 million related to these acquired sites. As of June 30, 2015, the Company has recorded monetary sanctions of $0.2 million associated with federal environmental regulations related to Spill Prevention, Control and Countermeasure Plans. The Company was assessed a penalty by the U.S. Environmental Protection Agency after a review of the Company’s implementation timing of its storage tank inspection plan. Foreign Environmental Matters. In connection with Koppers Inc.’s acquisition of the Osmose Entities, there are three plant sites located in the United Kingdom and Australia where the Company has recorded an environmental remediation liability for soil and groundwater contamination which occurred prior to the acquisition. As of June 30, 2015, the Company’s estimated environmental remediation liability for these acquired sites totals $8.5 million. The Company has also recorded a receivable under the Osmose Indemnity of $1.6 million related to these acquired sites. In December 2011, the Company ceased manufacturing operations at its Continental Carbon facility located in Kurnell, Australia. The Company has accrued its expected cost of site remediation resulting from the closure of $3.9 million as of June 30, 2015. Environmental Reserves Rollforward Period ended June 30, 2015 December 31, (Dollars in millions) Balance at beginning of year $ 7.8 $ 11.9 Expense 0.3 0.8 Reversal of reserves (0.1 ) (1.5 ) Cash expenditures (0.5 ) (3.7 ) Acquisition of Osmose Entities 13.6 0.7 Currency translation (0.3 ) (0.4 ) Balance at end of period $ 20.8 $ 7.8

Subsidiary Guarantor Informatio

Subsidiary Guarantor Information for Koppers Inc. Senior Notes	6 Months Ended
	Jun. 30, 2015
Text Block [Abstract]
Subsidiary Guarantor Information for Koppers Inc. Senior Notes	19. Subsidiary Guarantor Information for Koppers Inc. Senior Notes On December 1, 2009, Koppers Inc. issued $300.0 million principal value of Senior Notes. Koppers Holdings and each of Koppers Inc.’s 100 percent-owned material domestic subsidiaries other than Koppers Assurance, Inc. fully and unconditionally guarantee the payment of principal and interest on the Senior Notes. The domestic guarantor subsidiaries include Koppers World-Wide Ventures Corporation, Koppers Delaware, Inc., Koppers Concrete Products, Inc., Concrete Partners, Inc., and Koppers Asia LLC. Non-guarantor subsidiaries are owned directly by Koppers Inc. or are owned directly or indirectly by Koppers World-Wide Ventures Corporation. The guarantee of a guarantor subsidiary will be automatically and unconditionally released and discharged in the event of: ¡ any sale of the capital stock or substantially all of the assets of the guarantor subsidiary; ¡ the designation of the guarantor subsidiary as an unrestricted subsidiary in accordance with the indenture governing the Senior Notes; and ¡ the legal defeasance, covenant defeasance or satisfaction and discharge of the indenture governing the Senior Notes. Koppers Holdings depends on the dividends from the earnings of Koppers Inc. and its subsidiaries to generate the funds necessary to meet its financial obligations, including the payment of any declared dividend of Koppers Holdings. Koppers Inc.’s credit agreement prohibits it from making dividend payments to Koppers Holdings Inc. unless (1) such dividend payments are permitted by the indenture governing Koppers Inc.’s Senior Notes and (2) no event of default or potential default has occurred or is continuing under the credit agreement. The indenture governing Koppers Inc.’s Senior Notes restricts its ability to finance Koppers Holdings Inc.’s payment of dividends if (1) a default has occurred or would result from such financing, (2) a restricted subsidiary of Koppers Inc. which is not a guarantor under the indenture is not able to incur additional indebtedness (as defined in the indenture), and (3) the sum of all restricted payments (as defined in the indenture) have exceeded the permitted amount (referred to as the “basket”) at such point in time. The Koppers Inc. revolving credit facility agreement provides for a revolving credit facility of up to $500.0 million and a term loan of up to $300 million at variable rates. Borrowings under the revolving credit facility are secured by a first priority lien on substantially all of the assets of Koppers Inc. and its material domestic subsidiaries. The revolving credit facility contains certain covenants for Koppers Inc. and its restricted subsidiaries that limit capital expenditures, additional indebtedness, liens, dividends and 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. The amount of restricted net assets unavailable for distribution to Koppers Holdings Inc. by Koppers Inc. totals $37 million as of June 30, 2015. Cash dividends paid to Koppers Holdings Inc. by its subsidiaries totaled $5.8 million and $12.6 million for the six months ended June 30, 2015 and 2014, respectively. Condensed Consolidating Statement of Operations For the Three Months Ended June 30, 2015 Parent Koppers Inc. Domestic Non-Guarantor Subsidiaries Consolidating Consolidated (Dollars in millions) Net sales $ 0.0 $ 209.2 $ 97.0 $ 153.2 $ (27.8 ) $ 431.6 Cost of sales including depreciation and amortization 0.0 201.0 71.6 129.1 (27.2 ) 374.5 Selling, general and administrative 0.6 10.4 9.6 10.5 0.0 31.1 Operating (loss) profit (0.6 ) (2.2 ) 15.8 13.6 (0.6 ) 26.0 Other income (expense) 0.0 2.9 1.0 (3.1 ) (0.6 ) 0.2 Equity income of subsidiaries 9.1 22.3 5.5 0.0 (36.9 ) 0.0 Interest (income) expense (0.1 ) 11.5 (0.1 ) 2.2 (0.6 ) 12.9 Income taxes (0.4 ) 2.4 0.2 3.2 0.0 5.4 Income from continuing operations 9.0 9.1 22.2 5.1 (37.5 ) 7.9 Noncontrolling interests 0.0 0.0 0.0 (1.1 ) 0.0 (1.1 ) Net income attributable to Koppers $ 9.0 $ 9.1 $ 22.2 $ 6.2 $ (37.5 ) $ 9.0 Comprehensive loss attributable to Koppers $ 12.4 $ 12.3 $ 24.9 $ 9.0 $ (46.2 ) $ 12.4 Condensed Consolidating Statement of Operations For the Three Months Ended June 30, 2014 Parent Koppers Inc. Domestic Non-Guarantor Consolidating Consolidated (Dollars in millions) Net sales $ 0.0 $ 202.4 $ 7.2 $ 157.5 $ (10.3 ) $ 356.8 Cost of sales including depreciation and amortization 0.0 184.0 2.3 145.8 (10.5 ) 321.6 Selling, general and administrative 0.5 14.3 0.3 6.8 0.0 21.9 Operating (loss) profit (0.5 ) 4.1 4.6 4.9 0.2 13.3 Other income (expense) 0.0 0.1 0.9 (0.2 ) (1.1 ) (0.3 ) Equity income of subsidiaries 2.0 7.3 1.2 0.0 (10.5 ) 0.0 Interest expense 0.0 6.5 0.0 1.2 (1.1 ) 6.6 Income taxes (0.1 ) 2.9 0.1 2.7 0.0 5.6 Income from continuing operations 1.6 2.1 6.6 0.8 (10.3 ) 0.8 Discontinued operations 0.0 0.0 0.0 (0.1 ) 0.0 (0.1 ) Noncontrolling interests 0.0 0.0 0.0 (0.9 ) 0.0 (0.9 ) Net income attributable to Koppers $ 1.6 $ 2.1 $ 6.6 $ 1.6 $ (10.3 ) $ 1.6 Comprehensive income attributable to Koppers $ 4.1 $ 4.5 $ 8.7 $ 0.8 $ (14.0 ) $ 4.1 Condensed Consolidating Statement of Operations For the Six Months Ended June 30, 2015 Parent Koppers Inc. Domestic Non-Guarantor Consolidating Consolidated (Dollars in millions) Net sales $ 0.0 $ 397.0 $ 171.7 $ 309.2 $ (48.5 ) $ 829.4 Cost of sales including depreciation and amortization 0.0 385.6 131.6 265.1 (46.6 ) 735.7 Gain on sale of business 0.0 (3.2 ) 0.0 0.0 0.0 (3.2 ) Selling, general and administrative 1.1 22.2 18.6 21.0 0.0 62.9 Operating (loss) profit (1.1 ) (7.6 ) 21.5 23.1 (1.9 ) 34.0 Other income (expense) 0.0 3.1 2.0 (3.6 ) (1.1 ) 0.4 Equity income of subsidiaries 6.1 31.9 9.7 0.0 (47.7 ) 0.0 Interest expense 0.0 23.1 0.0 3.9 (1.1 ) 25.9 Income taxes (0.6 ) (1.8 ) 0.3 6.9 0.0 4.8 Income from continuing operations 5.6 6.1 32.9 8.7 (49.6 ) 3.7 Noncontrolling interests 0.0 0.0 0.0 (1.9 ) 0.0 (1.9 ) Net income attributable to Koppers $ 5.6 $ 6.1 $ 32.9 $ 10.6 $ (49.6 ) $ 5.6 Comprehensive (loss) income attributable to Koppers $ (1.2 ) $ (0.8 ) $ 24.6 $ 4.6 $ (28.4 ) $ (1.2 ) Condensed Consolidating Statement of Operations For the Six Months Ended June 30, 2014 Parent Koppers Inc. Domestic Non-Guarantor Consolidating Consolidated (Dollars in millions) Net sales $ 0.0 $ 380.0 $ 17.9 $ 311.4 $ (21.1 ) $ 688.2 Cost of sales including depreciation and amortization 0.0 344.9 9.2 298.3 (21.3 ) 631.1 Selling, general and administrative 1.0 27.8 0.6 13.9 0.0 43.3 Operating (loss) profit (1.0 ) 7.3 8.1 (0.8 ) 0.2 13.8 Other income (expense) 0.0 0.1 1.8 0.1 (2.1 ) (0.1 ) Equity income (loss) of subsidiaries 4.5 9.6 (7.0 ) 0.0 (7.1 ) 0.0 Interest expense 0.0 13.3 0.0 2.2 (2.1 ) 13.4 Income taxes (0.3 ) (0.8 ) (5.9 ) 6.6 0.0 (0.4 ) Income (loss) from continuing operations 3.8 4.5 8.8 (9.5 ) (6.9 ) 0.7 Discontinued operations 0.0 0.0 0.0 (0.1 ) 0.0 (0.1 ) Noncontrolling interests 0.0 0.0 0.0 (3.2 ) 0.0 (3.2 ) Net income (loss) attributable to Koppers $ 3.8 $ 4.5 $ 8.8 $ (6.4 ) $ (6.9 ) $ 3.8 Comprehensive income attributable to Koppers $ 9.4 $ 10.1 $ 13.6 $ 1.0 $ (24.7 ) $ 9.4 Condensed Consolidating Balance Sheet June 30, 2015 Parent Koppers Inc. Domestic Non-Guarantor Consolidating Consolidated (Dollars in millions) ASSETS Cash and cash equivalents $ 0.0 $ 0.3 $ 0.5 $ 50.4 $ 0.0 $ 51.2 Receivables, net 0.0 83.3 35.3 88.0 0.0 206.6 Affiliated receivables 0.0 15.1 10.7 18.5 (44.3 ) 0.0 Inventories, net 0.0 98.8 27.3 100.0 (2.7 ) 223.4 Deferred tax assets 0.0 10.1 (0.6 ) 4.1 0.0 13.6 Other current assets 0.0 4.9 4.1 34.4 0.0 43.4 Total current assets 0.0 212.5 77.3 295.4 (47.0 ) 538.2 Equity investments 69.9 792.6 215.1 2.4 (1,076.1 ) 3.9 Property, plant and equipment, net 0.0 120.4 42.6 128.9 0.0 291.9 Goodwill 0.0 43.9 152.9 59.8 0.0 256.6 Intangible assets, net 0.0 9.4 122.7 33.1 0.0 165.2 Deferred tax assets 0.0 (3.4 ) 5.1 6.6 0.0 8.3 Affiliated loan receivables 0.0 30.9 237.6 42.0 (310.5 ) 0.0 Other noncurrent assets 0.0 19.1 5.0 1.9 0.0 26.0 Total assets $ 69.9 $ 1,225.4 $ 858.3 $ 570.1 $ (1,433.6 ) $ 1,290.1 LIABILITIES AND EQUITY Accounts payable $ 0.1 $ 77.7 $ 28.1 $ 64.9 $ 0.0 $ 170.8 Affiliated payables 0.0 28.4 8.2 15.1 (51.7 ) 0.0 Accrued liabilities (0.6 ) 33.8 20.5 41.6 0.0 95.3 Short-term debt and current portion of long-term debt 0.0 30.3 0.0 15.1 0.0 45.4 Total current liabilities (0.5 ) 170.2 56.8 136.7 (51.7 ) 311.5 Long-term debt 0.0 706.1 0.0 42.7 0.0 748.8 Affiliated debt 0.0 209.6 30.8 70.1 (310.5 ) 0.0 Other long-term liabilities 0.0 68.2 13.0 69.7 0.0 150.9 Total liabilities (0.5 ) 1,154.1 100.6 319.2 (362.2 ) 1,211.2 Koppers shareholders’ equity 70.4 71.3 757.7 242.4 (1,071.4 ) 70.4 Noncontrolling interests 0.0 0.0 0.0 8.5 0.0 8.5 Total liabilities and equity $ 69.9 $ 1,225.4 $ 858.3 $ 570.1 $ (1,433.6 ) $ 1,290.1 Condensed Consolidating Balance Sheet December 31, 2014 Parent Koppers Inc. Domestic Non-Guarantor Consolidating Consolidated (Dollars in millions) ASSETS Cash and cash equivalents $ 0.0 $ 0.0 $ 0.9 $ 50.2 $ 0.0 $ 51.1 Receivables, net 0.0 75.7 20.0 103.0 0.0 198.7 Affiliated receivables 0.8 4.5 9.3 1.3 (15.9 ) 0.0 Inventories, net 0.0 108.8 30.8 102.6 (1.0 ) 241.2 Deferred tax assets 0.0 8.0 1.0 1.5 0.0 10.5 Other current assets 0.0 3.0 2.2 34.6 0.0 39.8 Total current assets 0.8 200.0 64.2 293.2 (16.9 ) 541.3 Equity investments 74.5 767.2 213.5 3.6 (1,053.8 ) 5.0 Property, plant and equipment, net 0.0 121.2 43.1 135.4 0.0 299.7 Goodwill 0.0 39.8 149.9 57.5 0.0 247.2 Intangible assets, net 0.0 2.2 128.1 37.4 0.0 167.7 Deferred tax assets 0.0 (1.0 ) 1.1 7.7 0.0 7.8 Affiliated loan receivables 0.0 40.5 212.0 40.9 (293.4 ) 0.0 Other noncurrent assets 0.0 19.1 5.2 0.9 0.0 25.2 Total assets $ 75.3 $ 1,189.0 $ 817.1 $ 576.6 $ (1,364.1 ) $ 1,293.9 LIABILITIES AND EQUITY Accounts payable $ 0.1 $ 60.9 $ 9.0 $ 50.6 $ 0.0 $ 120.6 Affiliated payables 0.0 13.2 2.7 13.5 (29.4 ) 0.0 Accrued liabilities 5.2 37.9 29.5 55.0 0.0 127.6 Short-term debt and current portion of long-term debt 0.0 30.0 0.0 13.9 0.0 43.9 Total current liabilities 5.3 142.0 41.2 133.0 (29.4 ) 292.1 Long-term debt 0.0 764.0 0.0 42.6 0.0 806.6 Affiliated debt 0.0 145.5 35.9 112.0 (293.4 ) 0.0 Other long-term liabilities 0.0 68.6 7.7 35.0 0.0 111.3 Total liabilities 5.3 1,120.1 84.8 322.6 (322.8 ) 1,210.0 Koppers shareholders’ equity 70.0 68.9 732.3 240.1 (1,041.3 ) 70.0 Noncontrolling interests 0.0 0.0 0.0 13.9 0.0 13.9 Total liabilities and equity $ 75.3 $ 1,189.0 $ 817.1 $ 576.6 ($ 1,364.1 ) $ 1,293.9 Condensed Consolidating Statement of Cash Flows For the Six Months Ended June 30, 2015 Parent Koppers Inc. Domestic Non-Guarantor Consolidating Consolidated (Dollars in millions) Cash provided by (used in) operating activities $ 5.4 $ 10.6 $ 32.2 $ 38.8 $ (8.9 ) $ 78.1 Cash provided by (used in) investing activities: Capital expenditures and acquisitions 0.0 (26.9 ) (3.1 ) (2.6 ) 0.0 (32.6 ) Repayments (loans to) from affiliates 0.0 5.1 (21.4 ) (1.1 ) 17.4 0.0 Net cash proceeds (payments) from divestitures and asset sales 0.0 12.2 0.0 0.3 0.0 12.5 Net cash (used in) provided by investing activities 0.0 (9.6 ) (24.5 ) (3.4 ) 17.4 (20.1 ) Cash provided by (used in) financing activities: (Repayments) borrowings of long-term debt 0.0 (57.9 ) 0.1 1.2 0.0 (56.6 ) Borrowings (repayments) of affiliated debt 0.0 64.0 (5.1 ) (41.5 ) (17.4 ) 0.0 Deferred financing costs 0.0 (1.0 ) 0.0 0.0 0.0 (1.0 ) Other financing activities 0.0 0.0 0.0 0.0 0.0 0.0 Dividends paid (5.1 ) (5.8 ) (3.1 ) (3.6 ) 8.9 (8.7 ) Stock repurchased (0.3 ) 0.0 0.0 0.0 0.0 (0.3 ) Net cash used in financing activities (5.4 ) (0.7 ) (8.1 ) (43.9 ) (8.5 ) (66.6 ) Effect of exchange rates on cash 0.0 0.0 0.0 8.7 0.0 8.7 Net increase (decrease) in cash and cash equivalents 0.0 0.3 (0.4 ) 0.2 0.0 0.1 Cash and cash equivalents at beginning of year 0.0 0.0 0.9 50.2 0.0 51.1 Cash and cash equivalents at end of period $ 0.0 $ 0.3 $ 0.5 $ 50.4 $ 0.0 $ 51.2 Condensed Consolidating Statement of Cash Flows For the Six Months Ended June 30, 2014 Parent Koppers Inc. Domestic Non-Guarantor Consolidating Consolidated (Dollars in millions) Cash provided by (used in) operating activities $ 11.5 $ (19.0 ) $ 17.1 $ 3.2 $ (21.5 ) $ (8.7 ) Cash provided by (used in) investing activities: Capital expenditures and acquisitions 0.0 (7.8 ) (15.0 ) (57.2 ) 14.8 (65.2 ) (Loans to) repayments from affiliates 0.0 (21.5 ) (23.7 ) 0.0 45.2 0.0 Net cash (used in) provided by investing activities 0.0 (29.3 ) (38.7 ) (57.2 ) 60.0 (65.2 ) Cash provided by (used in) financing activities: Borrowings (repayments) of long-term debt 0.0 24.3 0.0 31.2 0.0 55.5 Borrowings (repayments) of affiliated debt 0.0 6.7 21.5 17.0 (45.2 ) 0.0 Other financing activities 0.0 0.0 0.0 1.4 0.0 1.4 Dividends paid (10.2 ) (12.6 ) 0.0 (8.9 ) 21.5 (10.2 ) Stock (repurchased) issued (1.3 ) 0.0 0.0 14.8 (14.8 ) (1.3 ) Net cash (used in) provided by financing activities (11.5 ) 18.4 21.5 55.5 (38.5 ) 45.4 Effect of exchange rates on cash 0.0 0.0 0.0 0.7 0.0 0.7 Net (decrease) increase in cash and cash equivalents 0.0 (29.9 ) (0.1 ) 2.2 0.0 (27.8 ) Cash and cash equivalents at beginning of year 0.0 29.9 0.1 52.2 0.0 82.2 Cash and cash equivalents at end of period $ 0.0 $ 0.0 $ 0.0 $ 54.4 $ 0.0 $ 54.4

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2015
Related Party Transactions [Abstract]
Related Party Transactions	20. Related Party Transactions The Company has loaned $9.5 million to TKK, a 30-percent owned company in China. The loan is repayable in six equal installments beginning in June 2015. TKK defaulted on the first installment payment of $1.6 million due in June 2015 and, accordingly, the entire principal amount of the loan is currently due and payable. The Company has engaged in negotiations with TKK’s controlling shareholder regarding repayment of the loan in addition to the potential sale of the Company’s 30-percent interest in TKK. As of June 30, 2015, management has concluded that it is probable that the full principal amount of the loan remains collectible and the carrying value of $2.0 million related to its equity investment is recoverable, and accordingly, no provision has been recorded.

New Accounting Pronouncements (

New Accounting Pronouncements (Policies)	6 Months Ended
	Jun. 30, 2015
Accounting Changes and Error Corrections [Abstract]
New Accounting Pronouncements	In May 2015, the Financial Accounting Standards Board (“FASB”) issued guidance that removes from the fair value hierarchy investments for which fair value is measured at net asset value (or its equivalent) using the available practical expedient. The new guidance also modifies the scope of the disclosures related to such investments, eliminating from scope those investments eligible for but not actually valued using the practical expedient. Entities must continue to disclose information on investments for which fair value is measured at net asset value (or its equivalent) using the practical expedient, including information that helps readers understand the investments and whether the investments, if sold, are probable of being sold at amounts that differ from the net asset value. This guidance becomes effective January 1, 2016 and requires retrospective application. Early adoption is permitted. We are currently evaluating the impact this guidance will have on disclosures covering certain assets held by our pension plans. In April 2015, the FASB issued Accounting Standards Update (“ASU”) No. 2015-03, “Simplifying the Presentation of Debt Issuance Costs,” which requires companies to present debt issuance costs associated with a debt liability as a deduction from the carrying amount of that debt liability on the balance sheet rather than being capitalized as an asset. The standard is effective for interim and annual periods beginning after December 15, 2015, and retrospective presentation is required. The Company will adopt ASU No. 2015-03 on January 1, 2016 as required. ASU No. 2015-03 will not have a material effect on the Company’s results of operations, financial condition or liquidity. In February 2015, the FASB released updated consolidation guidance that entities must use to evaluate specific ownership and contractual arrangements that lead to a consolidation conclusion. The updates could change consolidation outcomes affecting presentation and disclosures. This guidance becomes effective January 1, 2016. We are currently evaluating the impact this guidance will have on our consolidated financial statements. In August 2014, the FASB issued ASU No. 2014-15, “Disclosure of Uncertainties About an Entity’s Ability to Continue as a Going Concern”, which requires management to perform interim and annual assessments of an entity’s ability to continue as a going concern within one year of the date the financial statements are issued and provides guidance on determining when and how to disclose going concern uncertainties in the financial statements. Certain disclosures will be required if conditions give rise to substantial doubt about an entity’s ability to continue as a going concern. ASU No. 2014-15 applies to all entities and is effective for annual and interim reporting periods ending after December 15, 2016, with early adoption permitted. We do not expect that the adoption of this standard will have a material effect on the Company’s financial statements. In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 requires an entity to recognize revenue in a manner that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, the amendment provides five steps that an entity should apply when recognizing revenue. The amendment also specifies the accounting of some costs to obtain or fulfill a contract with a customer and expands the disclosure requirements around contracts with customers. An entity can either adopt this amendment retrospectively to each prior reporting period presented or retrospectively with the cumulative effect of initially applying the update recognized at the date of initial application. In July 2015, the FASB adopted a one-year deferral of this guidance. As a result, this guidance will be effective January 1, 2018 with the option to adopt the standard as of the original effective date, January 1, 2017. The Company is currently evaluating the impact of the adoption of ASU 2014-09 on the Company’s financial statements. In January 2015, the Company adopted the amended guidance of ASC Topic 205, Presentation of Financial Statements (Topic 205) and ASC Topic 360, Property, Plant, and Equipment, which limit the definition of discontinued operations as only those disposals of components of an entity that represent a strategic shift that has (or will have) a major effect on an entity’s operations and financial results. The amended guidance also expands the definition of discontinued operations to include a business or nonprofit activity that, on acquisition, meets the criteria to be classified as held for sale and a disposal of an equity method investment that meets the definition of discontinued operations. The amended guidance requires the Company to report discontinued operations if (1) the component of an entity or group of components of an entity meets the criteria in Topic 205 to be classified as held for sale; (2) the component of an entity or group of components of an entity is disposed of by sale; or (3) the component of an entity or group of components of an entity is disposed other than by sale. We considered this amended guidance and determined the sale of the North American utility pole business should not be reported as a discontinued operation. The Company does not believe the sale of this business to have a major effect on the Company’s operations and financial results.

Plant Closures and Divestitur28

Plant Closures and Divestitures (Tables)	6 Months Ended
	Jun. 30, 2015
Discontinued Operations and Disposal Groups [Abstract]
Summary of Restructuring Activities and Related Reserves	Details of the restructuring activities and related reserves for past closures of certain of the Company’s facilities in the Netherlands, Australia and the United States are as follows: Severance and Environmental Site Other Total (Dollars in millions) Reserve at December 31, 2013 $ 0.1 $ 5.6 $ 3.3 $ 0.0 $ 9.0 Accrual 9.8 0.0 3.2 0.1 13.1 Reversal of accrued charges 0.0 (1.1 ) (0.9 ) 0.0 (2.0 ) Cash paid (9.7 ) 0.0 (1.3 ) 0.0 (11.0 ) Currency translation (0.2 ) (0.4 ) (0.4 ) 0.0 (1.0 ) Reserve at December 31, 2014 $ 0.0 $ 4.1 $ 3.9 $ 0.1 $ 8.1 Accrual 0.3 0.0 0.0 0.0 0.3 Reversal of accrued charges 0.0 0.0 (0.3 ) (0.1 ) (0.4 ) Cash paid 0.0 0.0 (1.5 ) 0.0 (1.5 ) Currency translation 0.0 (0.2 ) (0.3 ) 0.0 (0.5 ) Reserve at June 30, 2015 $ 0.3 $ 3.9 $ 1.8 $ 0.0 $ 6.0

Business Acquisitions (Tables)

Business Acquisitions (Tables)	6 Months Ended
	Jun. 30, 2015
Business Combinations [Abstract]
Summary of Company's Revenue and Net Income from Continuing Operations	The following unaudited pro forma information presents a summary of the Company’s revenues and net income from continuing operations as if the acquisition occurred on January 1, 2014. 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, 2014 and does not intend to project the future financial results of the Company after the acquisition of the Osmose Entities. The unaudited pro forma information is based on certain assumptions, which management believes are reasonable, and do not reflect the cost of any integration activities or the benefits from the acquisition and synergies that may be derived from any integration activities. Three months Six months (Dollars in millions) Revenue $ 470.1 $ 892.8 Income from continuing operations attributable to Koppers 12.5 13.0

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2015
Fair Value Disclosures [Abstract]
Schedule of Company's Financial Instruments	Carrying amounts and the related estimated fair values of the Company’s financial instruments as of June 30, 2015 and December 31, 2014 are as follows: June 30, 2015 December 31, 2014 Fair Value Carrying Fair Value Carrying (Dollars in millions) Financial assets: Cash and cash equivalents, including restricted cash $ 51.2 $ 51.2 $ 51.1 $ 51.1 Investments and other assets (a) 1.4 1.4 1.5 1.5 Financial liabilities: Long-term debt (including current portion) $ 806.2 $ 794.2 $ 862.1 $ 850.5 (a) Excludes equity method investments.

Comprehensive Income and Equi31

Comprehensive Income and Equity (Tables)	6 Months Ended
	Jun. 30, 2015
Equity [Abstract]
Schedule of Comprehensive Income	Total comprehensive income for the three and six months ended June 30, 2015 and 2014 is summarized in the table below: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 (Dollars in millions) Net income $ 7.9 $ 0.7 $ 3.7 $ 0.6 Other comprehensive income (loss): Change in currency translation adjustment 2.4 0.9 (8.2 ) 0.7 Change in foreign currency transactions of long-term subsidiary investments 0.0 1.0 0.0 3.4 Change in derivative financial instrument net loss, net of tax benefit (expense) of $0.1, $0.0, $0.2 and $0.0 (0.2 ) 0.0 (0.5 ) 0.0 Change in unrecognized pension net income, net of tax benefit (expense) of $(0.4), $(0.2), $(0.8) and $(0.5) 1.0 0.6 2.0 1.2 Change in unrecognized prior service cost, net of tax benefit (expense) of $0.0, $0.0, $0.0 and $0.0 0.0 0.0 (0.1 ) (0.1 ) Total comprehensive income (loss) 11.1 3.2 (3.1 ) 5.8 Less: comprehensive loss attributable to noncontrolling interests (1.1 ) (0.9 ) (1.9 ) (3.6 ) Comprehensive income (loss) attributable to Koppers $ 12.2 $ 4.1 $ (1.2 ) $ 9.4
Schedule of Change in Equity	The following tables present the change in equity for the six months ended June 30, 2015 and 2014, respectively: (Dollars in millions) Total Koppers Equity Noncontrolling Total Equity Balance at December 31, 2014 $ 70.0 $ 13.9 $ 83.9 Net income (loss) 5.6 (1.9 ) 3.7 Employee stock plans 2.0 0.0 2.0 Other comprehensive (loss) income (6.9 ) 0.0 (6.9 ) Dividends 0.0 (3.5 ) (3.5 ) Repurchases of common stock (0.3 ) 0.0 (0.3 ) Balance at June 30, 2015 $ 70.4 $ 8.5 $ 78.9 (Dollars in millions) Total Koppers Equity Noncontrolling Total Equity Balance at December 31, 2013 $ 169.8 $ 20.0 $ 189.8 Net income (loss) 3.8 (3.2 ) 0.6 Issuance of common stock 0.7 0.0 0.7 Employee stock plans 3.4 0.0 3.4 Other comprehensive income (loss) 5.6 (0.5 ) 5.1 Dividends (10.4 ) 0.0 (10.4 ) Investment in noncontrolling interests 0.0 1.4 1.4 Repurchases of common stock (2.0 ) 0.0 (2.0 ) Balance at June 30, 2014 $ 170.9 $ 17.7 $ 188.6

Earnings per Common Share (Tabl

Earnings per Common Share (Tables)	6 Months Ended
	Jun. 30, 2015
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: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 (Dollars in millions, except share amounts, in thousands, and per share amounts) Net income attributable to Koppers $ 9.0 $ 1.6 $ 5.6 $ 3.8 Less: loss from discontinued operations 0.0 (0.1 ) 0.0 (0.1 ) Income from continuing operations attributable to Koppers $ 9.0 $ 1.7 $ 5.6 $ 3.9 Weighted average common shares outstanding: Basic 20,545 20,475 20,529 20,430 Effect of dilutive securities 95 107 74 154 Diluted 20,640 20,582 20,603 20,584 Earnings per common share – continuing operations: Basic earnings per common share $ 0.44 $ 0.08 $ 0.28 $ 0.19 Diluted earnings per common share 0.44 0.08 0.27 0.19 Other data: Antidilutive securities excluded from computation of diluted earnings per common share 442 284 644 258

Stock-based Compensation (Table

Stock-based Compensation (Tables)	6 Months Ended
	Jun. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Performance Stock Units	The following table shows a summary of the performance stock units as of June 30, 2015: Performance Period Minimum Target Maximum 2013 – 2015 0 80,578 120,867 2014 – 2016 0 94,341 141,512 2015 – 2017 0 223,684 447,368
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 six months ended June 30, 2015: Restricted Stock Units Performance Stock Units Total Stock Units Weighted Average Non-vested at December 31, 2014 148,906 280,381 429,287 $ 39.31 Granted 141,775 223,684 365,459 $ 18.20 Credited from dividends 4,271 5,970 10,241 $ 37.78 Vested (62,929 ) 0 (62,929 ) $ 38.08 Forfeited (10,566 ) (106,031 ) (116,597 ) $ 38.49 Non-vested at June 30, 2015 221,457 404,004 625,461 $ 27.23
Stock Options Fair Value Assumptions	The fair value of stock options on the date of grant is calculated using the Black-Scholes-Merton model and the assumptions listed below: March 2015 Grant February 2014 Grant February 2013 Grant Grant date price per share of stock option award $ 17.57 $ 37.93 $ 42.76 Expected dividend yield per share 3.40 % 2.75 % 2.75 % Expected life in years 5.75 6.5 6.5 Expected volatility 42.27 % 52.14 % 53.77 % Risk-free interest rate 1.73 % 1.98 % 1.29 % Grant date fair value per share of option awards $ 5.20 $ 15.26 $ 17.28
Summary of Status and Activity of Stock Options	The following table shows a summary of the status and activity of stock options for the six months ended June 30, 2015: Options Weighted Average per Option Weighted Average (in years) Aggregate Intrinsic Outstanding at December 31, 2014 448,812 $ 36.58 Granted 330,159 $ 17.57 Forfeited (4,722 ) $ 39.23 Outstanding at June 30, 2015 774,249 $ 28.46 7.24 $ 2.6 Exercisable at June 30, 2015 333,697 $ 35.36 4.42 $ 0.2
Schedule of Stock-based Compensation Expense Recognized	Total stock-based compensation expense recognized for the three and six months ended June 30, 2015 and 2014 is as follows: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 (Dollars in millions) Stock-based compensation expense recognized: Selling, general and administrative expenses $ 1.3 $ 2.0 $ 2.0 $ 3.2 Less related income tax benefit 0.5 0.8 0.8 1.3 $ 0.8 $ 1.2 $ 1.2 $ 1.9

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 30, 2015
Segment Reporting [Abstract]
Summary of Results of Segment Operations	The following table sets forth certain sales and operating data, net of all intersegment transactions, for the Company’s segments for the periods indicated: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 (Dollars in millions) Revenues from external customers: Carbon Materials and Chemicals $ 158.4 $ 208.6 $ 316.6 $ 411.2 Railroad and Utility Products and Services 170.9 148.2 329.0 277.0 Performance Chemicals 102.3 0.0 183.8 0.0 Total $ 431.6 $ 356.8 $ 829.4 $ 688.2 Intersegment revenues: Carbon Materials and Chemicals $ 20.0 $ 20.1 $ 40.5 $ 41.3 Performance Chemicals 2.2 0.0 4.3 0.0 Total $ 22.2 $ 20.1 $ 44.8 $ 41.3 Depreciation and amortization expense: Carbon Materials and Chemicals (a) $ 6.5 $ 6.0 $ 12.7 $ 12.1 Railroad and Utility Products and Services (b) 6.4 3.7 10.5 6.5 Performance Chemicals 4.8 0.0 9.5 0.0 Total $ 17.7 $ 9.7 $ 32.7 $ 18.6 Operating profit (loss): Carbon Materials and Chemicals (c) $ (2.9 ) $ 3.8 $ (13.8 ) $ (5.0 ) Railroad and Utility Products and Services (d) 15.0 12.8 30.4 23.9 Performance Chemicals 15.5 0.0 21.9 0.0 Corporate (e) (1.6 ) (3.3 ) (4.5 ) (5.1 ) Total $ 26.0 $ 13.3 $ 34.0 $ 13.8 (a) Excludes impairment charges of $4.7 million for the six months ended June 30, 2014 for the Tangshan, China facility. (b) Excludes impairment charges of $2.5 million for the six months ended June 30, 2015 for a wood treating facility in the United States. (c) Includes plant closure costs of $10.8 million for the six months ended June 30, 2014 for the Uithoorn, the Netherlands facility and impairment charges of $4.7 million for the six months ended June 30, 2014 for the Tangshan, China facility. (d) Includes gain on sale of the Company’s North American utility pole business of $3.2 million and impairment charges of $2.5 million for a wood treating facility in the United States in the six months ended June 30, 2015. (e) Operating loss for Corporate includes general and administrative costs for Koppers Holdings Inc., the parent company of Koppers Inc., and foreign exchange revaluation related to intercompany loans in connection with a legal reorganization of the Company.
Summary of Tangible and Intangible Assets by Segments	The following table sets forth certain tangible and intangible assets allocated to each of the Company’s segments as of the dates indicated: June 30, 2015 December 31, 2014 (Dollars in millions) Segment assets: Carbon Materials and Chemicals $ 505.0 $ 514.6 Railroad and Utility Products and Services 267.7 275.2 Performance Chemicals 479.3 469.0 All other 38.1 35.1 Total $ 1,290.1 $ 1,293.9 Goodwill: Carbon Materials and Chemicals $ 68.3 $ 65.5 Railroad and Utility Products and Services 10.3 9.3 Performance Chemicals 178.0 172.4 Total $ 256.6 $ 247.2

Inventories (Tables)

Inventories (Tables)	6 Months Ended
	Jun. 30, 2015
Inventory Disclosure [Abstract]
Components of Inventories	Net inventories as of June 30, 2015 and December 31, 2014 are summarized in the table below: June 30, 2015 December 31, 2014 (Dollars in millions) Raw materials $ 166.6 $ 191.1 Work in process 16.1 2.6 Finished goods 98.2 103.6 280.9 297.3 Less revaluation to LIFO 57.5 56.1 Net $ 223.4 $ 241.2

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	6 Months Ended
	Jun. 30, 2015
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, plant and equipment as of June 30, 2015 and December 31, 2014 are summarized in the table below: June 30, 2015 December 31, 2014 (Dollars in millions) Land $ 18.1 $ 18.7 Buildings 41.7 45.3 Machinery and equipment 698.7 678.6 758.5 742.6 Less accumulated depreciation 466.6 442.9 Net $ 291.9 $ 299.7

Pensions and Postretirement B37

Pensions and Postretirement Benefit Plans (Tables)	6 Months Ended
	Jun. 30, 2015
Compensation and Retirement Disclosure [Abstract]
Components of Net Periodic Benefit Cost for Pension Plans and Other Benefit Plans	The following table provides the components of net periodic benefit cost for the pension plans and other benefit plans for the three and six months ended June 30, 2015 and 2014: Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 (Dollars in millions) Service cost $ 0.5 $ 0.6 $ 1.0 $ 1.2 Interest cost 2.6 3.1 5.4 6.0 Expected return on plan assets (3.0 ) (3.5 ) (6.0 ) (7.0 ) Amortization of prior service cost 0.0 (0.1 ) (0.1 ) (0.1 ) Amortization of net loss 1.7 1.0 3.3 2.0 Net periodic benefit cost $ 1.8 $ 1.1 $ 3.6 $ 2.1 Defined contribution plan expense (a) $ 2.0 $ 1.5 $ 2.0 $ 3.2 (a) The six months ended June 30, 2015 includes reversal of 2014 discretionary 401k match accrual of $2.2 million.

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2015
Debt Disclosure [Abstract]
Schedule of Long-Term Debt Instruments	Debt at June 30, 2015 and December 31, 2014 was as follows: Weighted Maturity June 30, 2015 December 31, 2014 (Dollars in millions) Term Loan 3 3 / 4 % 2019 $ 277.5 $ 292.5 Revolving Credit Facility 3 3 / 4 % 2019 161.3 204.5 Construction and other loans 5.81% 2018 58.1 56.5 Senior Notes 7 7 / 8 % 2019 297.3 297.0 Total debt 794.2 850.5 Less short term debt and current maturities of long-term debt 45.4 43.9 Long-term debt $ 748.8 $ 806.6

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	6 Months Ended
	Jun. 30, 2015
Asset Retirement Obligation Disclosure [Abstract]
Schedule of Changes in Carrying Values of Asset Retirement Obligations	The Company recognizes asset retirement obligations for the removal and disposal of residues; dismantling of certain tanks required by governmental authorities; cleaning and dismantling costs for owned rail cars; and cleaning costs for leased rail cars and barges. The following table reflects changes in the carrying values of asset retirement obligations: June 30, December 31, (Dollars in millions) Asset retirement obligation at beginning of year $ 30.5 $ 23.2 Acquisition 0.8 0.0 Accretion expense 1.5 2.3 Revision in estimated cash flows 3.3 10.3 Cash expenditures (3.5 ) (4.6 ) Currency translation (0.4 ) (0.7 ) Balance at end of period $ 32.2 $ 30.5

Deferred Revenue (Tables)

Deferred Revenue (Tables)	6 Months Ended
	Jun. 30, 2015
Deferred Revenue Disclosure [Abstract]
Deferred Revenue from Extended Product Warranty Liabilities	The Company defers revenues associated with extended product warranty liabilities based on historical loss experience and sales of extended warranties on certain products. In addition, the Company received an advance payment in 2015 related to an amendment to a 50-year supply agreement with a customer in China. The deferred revenue associated with this amendment will be amortized over the life of the underlying contract. The following table reflects changes in the carrying values of deferred revenue: June 30, December 31, (Dollars in millions) Balance at beginning of year $ 2.5 $ 3.2 Advance payment 29.6 0.0 Revenue earned (0.2 ) (0.7 ) Balance at end of period $ 31.9 $ 2.5

Commitments and Contingent Li41

Commitments and Contingent Liabilities (Tables)	6 Months Ended
	Jun. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Changes in Accrued Liability for Environmental Matters	The following table reflects changes in the accrued liability for environmental matters, of which $7.8 million and $3.3 million are classified as current liabilities at June 30, 2015 and December 31, 2014, respectively: Period ended June 30, 2015 December 31, (Dollars in millions) Balance at beginning of year $ 7.8 $ 11.9 Expense 0.3 0.8 Reversal of reserves (0.1 ) (1.5 ) Cash expenditures (0.5 ) (3.7 ) Acquisition of Osmose Entities 13.6 0.7 Currency translation (0.3 ) (0.4 ) Balance at end of period $ 20.8 $ 7.8

Subsidiary Guarantor Informat42

Subsidiary Guarantor Information for Koppers Inc. Senior Notes (Tables)	6 Months Ended
	Jun. 30, 2015
Text Block [Abstract]
Condensed Consolidating Statement of Operations	Condensed Consolidating Statement of Operations For the Three Months Ended June 30, 2015 Parent Koppers Inc. Domestic Non-Guarantor Subsidiaries Consolidating Consolidated (Dollars in millions) Net sales $ 0.0 $ 209.2 $ 97.0 $ 153.2 $ (27.8 ) $ 431.6 Cost of sales including depreciation and amortization 0.0 201.0 71.6 129.1 (27.2 ) 374.5 Selling, general and administrative 0.6 10.4 9.6 10.5 0.0 31.1 Operating (loss) profit (0.6 ) (2.2 ) 15.8 13.6 (0.6 ) 26.0 Other income (expense) 0.0 2.9 1.0 (3.1 ) (0.6 ) 0.2 Equity income of subsidiaries 9.1 22.3 5.5 0.0 (36.9 ) 0.0 Interest (income) expense (0.1 ) 11.5 (0.1 ) 2.2 (0.6 ) 12.9 Income taxes (0.4 ) 2.4 0.2 3.2 0.0 5.4 Income from continuing operations 9.0 9.1 22.2 5.1 (37.5 ) 7.9 Noncontrolling interests 0.0 0.0 0.0 (1.1 ) 0.0 (1.1 ) Net income attributable to Koppers $ 9.0 $ 9.1 $ 22.2 $ 6.2 $ (37.5 ) $ 9.0 Comprehensive loss attributable to Koppers $ 12.4 $ 12.3 $ 24.9 $ 9.0 $ (46.2 ) $ 12.4 Condensed Consolidating Statement of Operations For the Three Months Ended June 30, 2014 Parent Koppers Inc. Domestic Non-Guarantor Consolidating Consolidated (Dollars in millions) Net sales $ 0.0 $ 202.4 $ 7.2 $ 157.5 $ (10.3 ) $ 356.8 Cost of sales including depreciation and amortization 0.0 184.0 2.3 145.8 (10.5 ) 321.6 Selling, general and administrative 0.5 14.3 0.3 6.8 0.0 21.9 Operating (loss) profit (0.5 ) 4.1 4.6 4.9 0.2 13.3 Other income (expense) 0.0 0.1 0.9 (0.2 ) (1.1 ) (0.3 ) Equity income of subsidiaries 2.0 7.3 1.2 0.0 (10.5 ) 0.0 Interest expense 0.0 6.5 0.0 1.2 (1.1 ) 6.6 Income taxes (0.1 ) 2.9 0.1 2.7 0.0 5.6 Income from continuing operations 1.6 2.1 6.6 0.8 (10.3 ) 0.8 Discontinued operations 0.0 0.0 0.0 (0.1 ) 0.0 (0.1 ) Noncontrolling interests 0.0 0.0 0.0 (0.9 ) 0.0 (0.9 ) Net income attributable to Koppers $ 1.6 $ 2.1 $ 6.6 $ 1.6 $ (10.3 ) $ 1.6 Comprehensive income attributable to Koppers $ 4.1 $ 4.5 $ 8.7 $ 0.8 $ (14.0 ) $ 4.1 Condensed Consolidating Statement of Operations For the Six Months Ended June 30, 2015 Parent Koppers Inc. Domestic Non-Guarantor Consolidating Consolidated (Dollars in millions) Net sales $ 0.0 $ 397.0 $ 171.7 $ 309.2 $ (48.5 ) $ 829.4 Cost of sales including depreciation and amortization 0.0 385.6 131.6 265.1 (46.6 ) 735.7 Gain on sale of business 0.0 (3.2 ) 0.0 0.0 0.0 (3.2 ) Selling, general and administrative 1.1 22.2 18.6 21.0 0.0 62.9 Operating (loss) profit (1.1 ) (7.6 ) 21.5 23.1 (1.9 ) 34.0 Other income (expense) 0.0 3.1 2.0 (3.6 ) (1.1 ) 0.4 Equity income of subsidiaries 6.1 31.9 9.7 0.0 (47.7 ) 0.0 Interest expense 0.0 23.1 0.0 3.9 (1.1 ) 25.9 Income taxes (0.6 ) (1.8 ) 0.3 6.9 0.0 4.8 Income from continuing operations 5.6 6.1 32.9 8.7 (49.6 ) 3.7 Noncontrolling interests 0.0 0.0 0.0 (1.9 ) 0.0 (1.9 ) Net income attributable to Koppers $ 5.6 $ 6.1 $ 32.9 $ 10.6 $ (49.6 ) $ 5.6 Comprehensive (loss) income attributable to Koppers $ (1.2 ) $ (0.8 ) $ 24.6 $ 4.6 $ (28.4 ) $ (1.2 ) Condensed Consolidating Statement of Operations For the Six Months Ended June 30, 2014 Parent Koppers Inc. Domestic Non-Guarantor Consolidating Consolidated (Dollars in millions) Net sales $ 0.0 $ 380.0 $ 17.9 $ 311.4 $ (21.1 ) $ 688.2 Cost of sales including depreciation and amortization 0.0 344.9 9.2 298.3 (21.3 ) 631.1 Selling, general and administrative 1.0 27.8 0.6 13.9 0.0 43.3 Operating (loss) profit (1.0 ) 7.3 8.1 (0.8 ) 0.2 13.8 Other income (expense) 0.0 0.1 1.8 0.1 (2.1 ) (0.1 ) Equity income (loss) of subsidiaries 4.5 9.6 (7.0 ) 0.0 (7.1 ) 0.0 Interest expense 0.0 13.3 0.0 2.2 (2.1 ) 13.4 Income taxes (0.3 ) (0.8 ) (5.9 ) 6.6 0.0 (0.4 ) Income (loss) from continuing operations 3.8 4.5 8.8 (9.5 ) (6.9 ) 0.7 Discontinued operations 0.0 0.0 0.0 (0.1 ) 0.0 (0.1 ) Noncontrolling interests 0.0 0.0 0.0 (3.2 ) 0.0 (3.2 ) Net income (loss) attributable to Koppers $ 3.8 $ 4.5 $ 8.8 $ (6.4 ) $ (6.9 ) $ 3.8 Comprehensive income attributable to Koppers $ 9.4 $ 10.1 $ 13.6 $ 1.0 $ (24.7 ) $ 9.4
Condensed Consolidating Balance Sheet	Condensed Consolidating Balance Sheet June 30, 2015 Parent Koppers Inc. Domestic Non-Guarantor Consolidating Consolidated (Dollars in millions) ASSETS Cash and cash equivalents $ 0.0 $ 0.3 $ 0.5 $ 50.4 $ 0.0 $ 51.2 Receivables, net 0.0 83.3 35.3 88.0 0.0 206.6 Affiliated receivables 0.0 15.1 10.7 18.5 (44.3 ) 0.0 Inventories, net 0.0 98.8 27.3 100.0 (2.7 ) 223.4 Deferred tax assets 0.0 10.1 (0.6 ) 4.1 0.0 13.6 Other current assets 0.0 4.9 4.1 34.4 0.0 43.4 Total current assets 0.0 212.5 77.3 295.4 (47.0 ) 538.2 Equity investments 69.9 792.6 215.1 2.4 (1,076.1 ) 3.9 Property, plant and equipment, net 0.0 120.4 42.6 128.9 0.0 291.9 Goodwill 0.0 43.9 152.9 59.8 0.0 256.6 Intangible assets, net 0.0 9.4 122.7 33.1 0.0 165.2 Deferred tax assets 0.0 (3.4 ) 5.1 6.6 0.0 8.3 Affiliated loan receivables 0.0 30.9 237.6 42.0 (310.5 ) 0.0 Other noncurrent assets 0.0 19.1 5.0 1.9 0.0 26.0 Total assets $ 69.9 $ 1,225.4 $ 858.3 $ 570.1 $ (1,433.6 ) $ 1,290.1 LIABILITIES AND EQUITY Accounts payable $ 0.1 $ 77.7 $ 28.1 $ 64.9 $ 0.0 $ 170.8 Affiliated payables 0.0 28.4 8.2 15.1 (51.7 ) 0.0 Accrued liabilities (0.6 ) 33.8 20.5 41.6 0.0 95.3 Short-term debt and current portion of long-term debt 0.0 30.3 0.0 15.1 0.0 45.4 Total current liabilities (0.5 ) 170.2 56.8 136.7 (51.7 ) 311.5 Long-term debt 0.0 706.1 0.0 42.7 0.0 748.8 Affiliated debt 0.0 209.6 30.8 70.1 (310.5 ) 0.0 Other long-term liabilities 0.0 68.2 13.0 69.7 0.0 150.9 Total liabilities (0.5 ) 1,154.1 100.6 319.2 (362.2 ) 1,211.2 Koppers shareholders’ equity 70.4 71.3 757.7 242.4 (1,071.4 ) 70.4 Noncontrolling interests 0.0 0.0 0.0 8.5 0.0 8.5 Total liabilities and equity $ 69.9 $ 1,225.4 $ 858.3 $ 570.1 $ (1,433.6 ) $ 1,290.1 Condensed Consolidating Balance Sheet December 31, 2014 Parent Koppers Inc. Domestic Non-Guarantor Consolidating Consolidated (Dollars in millions) ASSETS Cash and cash equivalents $ 0.0 $ 0.0 $ 0.9 $ 50.2 $ 0.0 $ 51.1 Receivables, net 0.0 75.7 20.0 103.0 0.0 198.7 Affiliated receivables 0.8 4.5 9.3 1.3 (15.9 ) 0.0 Inventories, net 0.0 108.8 30.8 102.6 (1.0 ) 241.2 Deferred tax assets 0.0 8.0 1.0 1.5 0.0 10.5 Other current assets 0.0 3.0 2.2 34.6 0.0 39.8 Total current assets 0.8 200.0 64.2 293.2 (16.9 ) 541.3 Equity investments 74.5 767.2 213.5 3.6 (1,053.8 ) 5.0 Property, plant and equipment, net 0.0 121.2 43.1 135.4 0.0 299.7 Goodwill 0.0 39.8 149.9 57.5 0.0 247.2 Intangible assets, net 0.0 2.2 128.1 37.4 0.0 167.7 Deferred tax assets 0.0 (1.0 ) 1.1 7.7 0.0 7.8 Affiliated loan receivables 0.0 40.5 212.0 40.9 (293.4 ) 0.0 Other noncurrent assets 0.0 19.1 5.2 0.9 0.0 25.2 Total assets $ 75.3 $ 1,189.0 $ 817.1 $ 576.6 $ (1,364.1 ) $ 1,293.9 LIABILITIES AND EQUITY Accounts payable $ 0.1 $ 60.9 $ 9.0 $ 50.6 $ 0.0 $ 120.6 Affiliated payables 0.0 13.2 2.7 13.5 (29.4 ) 0.0 Accrued liabilities 5.2 37.9 29.5 55.0 0.0 127.6 Short-term debt and current portion of long-term debt 0.0 30.0 0.0 13.9 0.0 43.9 Total current liabilities 5.3 142.0 41.2 133.0 (29.4 ) 292.1 Long-term debt 0.0 764.0 0.0 42.6 0.0 806.6 Affiliated debt 0.0 145.5 35.9 112.0 (293.4 ) 0.0 Other long-term liabilities 0.0 68.6 7.7 35.0 0.0 111.3 Total liabilities 5.3 1,120.1 84.8 322.6 (322.8 ) 1,210.0 Koppers shareholders’ equity 70.0 68.9 732.3 240.1 (1,041.3 ) 70.0 Noncontrolling interests 0.0 0.0 0.0 13.9 0.0 13.9 Total liabilities and equity $ 75.3 $ 1,189.0 $ 817.1 $ 576.6 ($ 1,364.1 ) $ 1,293.9
Condensed Consolidating Statement of Cash Flows	Condensed Consolidating Statement of Cash Flows For the Six Months Ended June 30, 2015 Parent Koppers Inc. Domestic Non-Guarantor Consolidating Consolidated (Dollars in millions) Cash provided by (used in) operating activities $ 5.4 $ 10.6 $ 32.2 $ 38.8 $ (8.9 ) $ 78.1 Cash provided by (used in) investing activities: Capital expenditures and acquisitions 0.0 (26.9 ) (3.1 ) (2.6 ) 0.0 (32.6 ) Repayments (loans to) from affiliates 0.0 5.1 (21.4 ) (1.1 ) 17.4 0.0 Net cash proceeds (payments) from divestitures and asset sales 0.0 12.2 0.0 0.3 0.0 12.5 Net cash (used in) provided by investing activities 0.0 (9.6 ) (24.5 ) (3.4 ) 17.4 (20.1 ) Cash provided by (used in) financing activities: (Repayments) borrowings of long-term debt 0.0 (57.9 ) 0.1 1.2 0.0 (56.6 ) Borrowings (repayments) of affiliated debt 0.0 64.0 (5.1 ) (41.5 ) (17.4 ) 0.0 Deferred financing costs 0.0 (1.0 ) 0.0 0.0 0.0 (1.0 ) Other financing activities 0.0 0.0 0.0 0.0 0.0 0.0 Dividends paid (5.1 ) (5.8 ) (3.1 ) (3.6 ) 8.9 (8.7 ) Stock repurchased (0.3 ) 0.0 0.0 0.0 0.0 (0.3 ) Net cash used in financing activities (5.4 ) (0.7 ) (8.1 ) (43.9 ) (8.5 ) (66.6 ) Effect of exchange rates on cash 0.0 0.0 0.0 8.7 0.0 8.7 Net increase (decrease) in cash and cash equivalents 0.0 0.3 (0.4 ) 0.2 0.0 0.1 Cash and cash equivalents at beginning of year 0.0 0.0 0.9 50.2 0.0 51.1 Cash and cash equivalents at end of period $ 0.0 $ 0.3 $ 0.5 $ 50.4 $ 0.0 $ 51.2 Condensed Consolidating Statement of Cash Flows For the Six Months Ended June 30, 2014 Parent Koppers Inc. Domestic Non-Guarantor Consolidating Consolidated (Dollars in millions) Cash provided by (used in) operating activities $ 11.5 $ (19.0 ) $ 17.1 $ 3.2 $ (21.5 ) $ (8.7 ) Cash provided by (used in) investing activities: Capital expenditures and acquisitions 0.0 (7.8 ) (15.0 ) (57.2 ) 14.8 (65.2 ) (Loans to) repayments from affiliates 0.0 (21.5 ) (23.7 ) 0.0 45.2 0.0 Net cash (used in) provided by investing activities 0.0 (29.3 ) (38.7 ) (57.2 ) 60.0 (65.2 ) Cash provided by (used in) financing activities: Borrowings (repayments) of long-term debt 0.0 24.3 0.0 31.2 0.0 55.5 Borrowings (repayments) of affiliated debt 0.0 6.7 21.5 17.0 (45.2 ) 0.0 Other financing activities 0.0 0.0 0.0 1.4 0.0 1.4 Dividends paid (10.2 ) (12.6 ) 0.0 (8.9 ) 21.5 (10.2 ) Stock (repurchased) issued (1.3 ) 0.0 0.0 14.8 (14.8 ) (1.3 ) Net cash (used in) provided by financing activities (11.5 ) 18.4 21.5 55.5 (38.5 ) 45.4 Effect of exchange rates on cash 0.0 0.0 0.0 0.7 0.0 0.7 Net (decrease) increase in cash and cash equivalents 0.0 (29.9 ) (0.1 ) 2.2 0.0 (27.8 ) Cash and cash equivalents at beginning of year 0.0 29.9 0.1 52.2 0.0 82.2 Cash and cash equivalents at end of period $ 0.0 $ 0.0 $ 0.0 $ 54.4 $ 0.0 $ 54.4

Plant Closures and Divestitur43

Plant Closures and Divestitures - Additional Information (Detail) - USD ($) $ in Millions	Jan. 16, 2015	Mar. 31, 2015	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Restructuring Cost and Reserve [Line Items]
Gain (loss) on sale of business			$ 0	$ 0	$ 3.2	$ 0
Cash received from sale of business					12.5	0
Impairment charges					2.7	$ 4.7
North American Utility Pole Business [Member]
Restructuring Cost and Reserve [Line Items]
Gain (loss) on sale of business	$ 3.2
Promissory note received	1.3
Cash received from sale of business	$ 12.3
Railroad and Utility Products and Services [Member]
Restructuring Cost and Reserve [Line Items]
Impairment charges					2.5
Railroad and Utility Products and Services [Member] | West Virginia [Member]
Restructuring Cost and Reserve [Line Items]
Impairment charges					$ 0.4
Severance and fixed asset impairment charge		$ 2.7

Plant Closures and Divestitur44

Plant Closures and Divestitures - Summary of Restructuring Activities and Related Reserves (Detail) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Reserve, Beginning Balance	$ 8.1	$ 9
Accrual	0.3	13.1
Reversal of accrued charges	(0.4)	(2)
Cash paid	(1.5)	(11)
Currency translation	(0.5)	(1)
Reserve, Ending Balance	6	8.1
Severance and Employee Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Reserve, Beginning Balance	0	0.1
Accrual	0.3	9.8
Reversal of accrued charges	0	0
Cash paid	0	(9.7)
Currency translation	0	(0.2)
Reserve, Ending Balance	0.3	0
Environmental Remediation [Member]
Restructuring Cost and Reserve [Line Items]
Reserve, Beginning Balance	4.1	5.6
Accrual	0	0
Reversal of accrued charges	0	(1.1)
Cash paid	0	0
Currency translation	(0.2)	(0.4)
Reserve, Ending Balance	3.9	4.1
Site Demolition [Member]
Restructuring Cost and Reserve [Line Items]
Reserve, Beginning Balance	3.9	3.3
Accrual	0	3.2
Reversal of accrued charges	(0.3)	(0.9)
Cash paid	(1.5)	(1.3)
Currency translation	(0.3)	(0.4)
Reserve, Ending Balance	1.8	3.9
Other [Member]
Restructuring Cost and Reserve [Line Items]
Reserve, Beginning Balance	0.1	0
Accrual	0	0.1
Reversal of accrued charges	(0.1)	0
Cash paid	0	0
Currency translation	0	0
Reserve, Ending Balance	$ 0	$ 0.1

Business Acquisitions - Additio

Business Acquisitions - Additional Information (Detail) - USD ($)	Jan. 16, 2015	Aug. 15, 2014	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Business Acquisition [Line Items]
Intangible assets, deductible goodwill				$ 256,600,000		$ 247,200,000
Business acquisition cash payment				15,300,000	$ 29,600,000
Net increase in goodwill				$ 9,200,000
KMG Chemicals Inc [Member]
Business Acquisition [Line Items]
Business acquisition purchase price	$ 15,100,000
Acquired assets, inventory	3,000,000
KMG Chemicals Inc [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Intangible assets, primarily customer relationships	$ 7,800,000
Customer contracts, amortization period	18 years
KMG Chemicals Inc [Member] | Carbon Materials and Chemicals [Member]
Business Acquisition [Line Items]
Intangible assets, deductible goodwill	$ 4,200,000
Osmose Holdings, Inc. [Member]
Business Acquisition [Line Items]
Business acquisition cash payment		$ 494,100,000
Cash acquired		27,200,000
Acquisition-related costs reported in selling, general and administrative expenses			$ 2,700,000		$ 4,100,000
Osmose Holdings, Inc. [Member] | Senior Secured Credit Facilities [Member]
Business Acquisition [Line Items]
Revolving credit facility		500,000,000
Osmose Holdings, Inc. [Member] | Term Loan Facility [Member]
Business Acquisition [Line Items]
Revolving credit facility		$ 300,000,000

Business Acquisitions - Summary

Business Acquisitions - Summary of Company's Revenue And Net Income From Continuing Operations (Detail) - Jun. 30, 2014 - USD ($) $ in Millions	Total	Total
Business Acquisition, Pro Forma Information [Abstract]
Revenue	$ 470.1	$ 892.8
Income from continuing operations attributable to Koppers	$ 12.5	$ 13

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Company's Financial Instruments (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Fair Value [Member]
Financial assets:
Cash and cash equivalents, including restricted cash	$ 51.2	$ 51.1
Investments and other assets	1.4	1.5
Financial liabilities:
Long-term debt (including current portion)	806.2	862.1
Carrying Value [Member]
Financial assets:
Cash and cash equivalents, including restricted cash	51.2	51.1
Investments and other assets	1.4	1.5
Financial liabilities:
Long-term debt (including current portion)	$ 794.2	$ 850.5

Comprehensive Income and Equi48

Comprehensive Income and Equity - Schedule of Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Equity [Abstract]
Net income	$ 7.9	$ 0.7	$ 3.7	$ 0.6
Other comprehensive income (loss):
Change in currency translation adjustment	2.4	0.9	(8.2)	0.7
Change in foreign currency transactions of long-term subsidiary investments	0	1	0	3.4
Change in derivative financial instrument net loss, net of tax benefit (expense) of $0.1, $0.0, $0.2 and $0.0	(0.2)	0	(0.5)	0
Change in unrecognized pension net income, net of tax benefit (expense) of $(0.4), $(0.2), $(0.8) and $(0.5)	1	0.6	2	1.2
Change in unrecognized prior service cost, net of tax benefit (expense) of $0.0, $0.0, $0.0 and $0.0	0	0	(0.1)	(0.1)
Total comprehensive income (loss)	11.1	3.2	(3.1)	5.8
Less: comprehensive loss attributable to noncontrolling interests	(1.1)	(0.9)	(1.9)	(3.6)
Comprehensive income (loss) attributable to Koppers	$ 12.2	$ 4.1	$ (1.2)	$ 9.4

Comprehensive Income and Equi49

Comprehensive Income and Equity - Schedule of Comprehensive Income (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Equity [Abstract]
Tax benefit (expense), derivative financial instrument	$ 0.1	$ 0	$ 0.2	$ 0
Tax benefit (expense), unrecognized pension net income	(0.4)	(0.2)	(0.8)	(0.5)
Tax benefit (expense), unrecognized prior service cost	$ 0	$ 0	$ 0	$ 0

Comprehensive Income and Equi50

Comprehensive Income and Equity - Additional Information (Detail) - Jun. 30, 2015 - USD ($) $ in Millions	Total	Total
Equity [Abstract]
Loss related to derivative instrument	$ 1	$ 1.9

Comprehensive Income and Equi51

Comprehensive Income and Equity - Schedule of Change in Equity (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance			$ 83.9	$ 189.8
Net income (loss)	$ 7.9	$ 0.7	3.7	0.6
Issuance of common stock				0.7
Employee stock plans			2	3.4
Other comprehensive (loss) income			(6.9)	5.1
Dividends			(3.5)	(10.4)
Investment in noncontrolling interests				1.4
Repurchases of common stock			(0.3)	(2)
Balance	78.9	188.6	78.9	188.6
Total Koppers Shareholders' Equity [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance			70	169.8
Net income (loss)			5.6	3.8
Issuance of common stock				0.7
Employee stock plans			2	3.4
Other comprehensive (loss) income			(6.9)	5.6
Dividends			0	(10.4)
Investment in noncontrolling interests				0
Repurchases of common stock			(0.3)	(2)
Balance	70.4	170.9	70.4	170.9
Noncontrolling Interests [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance			13.9	20
Net income (loss)			(1.9)	(3.2)
Issuance of common stock				0
Employee stock plans			0	0
Other comprehensive (loss) income			0	(0.5)
Dividends			(3.5)	0
Investment in noncontrolling interests				1.4
Repurchases of common stock			0	0
Balance	$ 8.5	$ 17.7	$ 8.5	$ 17.7

Earnings per Common Share - Sch

Earnings per Common Share - Schedule of Computation of Basic and Diluted Earnings per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Net income (loss) attributable to Koppers	$ 9	$ 1.6	$ 5.6	$ 3.8
Less: loss from discontinued operations	0	(0.1)	0	(0.1)
Income from continuing operations attributable to Koppers	$ 9	$ 1.7	$ 5.6	$ 3.9
Weighted average common shares outstanding:
Basic	20,545	20,475	20,529	20,430
Effect of dilutive securities	95	107	74	154
Diluted	20,640	20,582	20,603	20,584
Earnings per common share - continuing operations:
Basic earnings per common share	$ 0.44	$ 0.08	$ 0.28	$ 0.19
Diluted earnings per common share	$ 0.44	$ 0.08	$ 0.27	$ 0.19
Other data:
Antidilutive securities excluded from computation of diluted earnings per common share	442	284	644	258

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Detail) - Jun. 30, 2015 - USD ($) $ in Millions	Total
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Future gross compensation expense related to non-vested stock-based compensation arrangements, which are expected to vest	$ 8.9
Future compensation expense, weighted-average expected period of recognition in months	31 months
Board of Directors [Member] | Restricted Stock Units (RSUs) [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Stock options, vesting period	1 year
Executive Officer [Member] | Employee Stock Option [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Stock options, vesting period	4 years
March 2015 Grant [Member] | Performance Stock Units [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Percentage of target award earned by participants	200.00%
Vesting performance stock units if minimum performance criteria are not achieved	0
Stock options, vesting period	3 years
March 2015 Grant [Member] | Performance Stock Units [Member] | Minimum [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Percentage of target award earned by participants	0.00%
March 2015 Grant [Member] | Performance Stock Units [Member] | Maximum [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Percentage of target award earned by participants	150.00%
March 2015 Grant [Member] | Restricted Stock Units (RSUs) [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Stock options, vesting period	4 years
March 2015 Grant [Member] | Employee Stock Option [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Stock options, term in years	10 years
March 2015 Grant [Member] | Executive Officer [Member] | Employee Stock Option [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Stock options, vesting period	3 years

Stock-based Compensation - Summ

Stock-based Compensation - Summary of Performance Stock Units (Detail) - shares	Jun. 30, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	625,461	429,287
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	404,004	280,381
Minimum [Member] | 2013 - 2015 [Member] | Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	0
Minimum [Member] | 2014 - 2016 [Member] | Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	0
Minimum [Member] | 2015 - 2017 [Member] | Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	0
Target Shares [Member] | 2013 - 2015 [Member] | Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	80,578
Target Shares [Member] | 2014 - 2016 [Member] | Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	94,341
Target Shares [Member] | 2015 - 2017 [Member] | Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	223,684
Maximum [Member] | 2013 - 2015 [Member] | Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	120,867
Maximum [Member] | 2014 - 2016 [Member] | Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	141,512
Maximum [Member] | 2015 - 2017 [Member] | Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding	447,368

Stock-based Compensation - Su55

Stock-based Compensation - Summary of Status and Activity of Non-Vested Stock Awards (Detail) - 6 months ended Jun. 30, 2015 - $ / shares	Total
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested, Beginning Balance	429,287
Granted	365,459
Credited from dividends	10,241
Vested	(62,929)
Forfeited	(116,597)
Non-vested, Ending Balance	625,461
Beginning Balance, Non-vested, Weighted Average Grant Date Fair Value per Unit	$ 39.31
Granted, Weighted Average Grant Date Fair Value per Unit	18.20
Credited from dividends, Weighted Average Grant Date Fair Value per Unit	37.78
Vested, Weighted Average Grant Date Fair Value per Unit	38.08
Forfeited, Weighted Average Grant Date Fair Value per Unit	38.49
Ending Balance, Non-vested, Weighted Average Grant Date Fair Value per Unit	$ 27.23
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested, Beginning Balance	148,906
Granted	141,775
Credited from dividends	4,271
Vested	(62,929)
Forfeited	(10,566)
Non-vested, Ending Balance	221,457
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested, Beginning Balance	280,381
Granted	223,684
Credited from dividends	5,970
Vested	0
Forfeited	(106,031)
Non-vested, Ending Balance	404,004

Stock-based Compensation - Stoc

Stock-based Compensation - Stock Options Fair Value Assumptions (Detail) - Jun. 30, 2015 - $ / shares	Total
March 2015 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of stock option award	$ 17.57
Expected dividend yield per share	3.40%
Expected life in years	5 years 9 months
Expected volatility	42.27%
Risk-free interest rate	1.73%
Grant date fair value per share of option awards	$ 5.20
February 2014 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of stock option award	$ 37.93
Expected dividend yield per share	2.75%
Expected life in years	6 years 6 months
Expected volatility	52.14%
Risk-free interest rate	1.98%
Grant date fair value per share of option awards	$ 15.26
February 2013 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date price per share of stock option award	$ 42.76
Expected dividend yield per share	2.75%
Expected life in years	6 years 6 months
Expected volatility	53.77%
Risk-free interest rate	1.29%
Grant date fair value per share of option awards	$ 17.28

Stock-based Compensation - Su57

Stock-based Compensation - Summary of Status and Activity of Stock Options (Detail) - Jun. 30, 2015 - USD ($) $ / shares in Units, $ in Millions	Total
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Options, Outstanding at December 31, 2014	448,812
Options, Granted	330,159
Options, Forfeited	(4,722)
Options, Outstanding at June 30, 2015	774,249
Options, Exercisable at June 30, 2015	333,697
Weighted Average Exercise Price per Option, Outstanding at December 31, 2014	$ 36.58
Weighted Average Exercise Price per Option, Granted	17.57
Weighted Average Exercise Price per Option, Forfeited	39.23
Weighted Average Exercise Price per Option, Outstanding at June 30, 2015	28.46
Weighted Average Exercise Price per Option, Exercisable at June 30, 2015	$ 35.36
Weighted Average Remaining Contractual Term, Outstanding at June 30, 2015	7 years 2 months 27 days
Weighted Average Remaining Contractual Term, Exercisable at June 30, 2015	4 years 5 months 1 day
Outstanding at June 30, 2015	$ 2.6
Exercisable at June 30, 2015	$ 0.2

Stock-based Compensation - Sche

Stock-based Compensation - Schedule of Stock-Based Compensation Expense Recognized (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Stock-based compensation expense recognized:
Selling, general and administrative expenses	$ 1.3	$ 2	$ 2	$ 3.2
Less related income tax benefit	0.5	0.8	0.8	1.3
Decrease in net income attributable to Koppers	$ 0.8	$ 1.2	$ 1.2	$ 1.9

Segment Information - Additiona

Segment Information - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2015Segment
Segment Reporting [Abstract]
Number of reportable segments	3

Segment Information - Summary o

Segment Information - Summary of Results of Segment Operations (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenues from external customers:
Revenues from external customers	$ 431.6	$ 356.8	$ 829.4	$ 688.2
Intersegment revenues:
Intersegment revenues	(431.6)	(356.8)	(829.4)	(688.2)
Depreciation and amortization expense:
Depreciation and amortization expense	17.7	9.7	32.7	18.6
Operating profit (loss)
Operating profit (loss)	26	13.3	34	13.8
Operating Segments [Member] | Carbon Materials and Chemicals [Member]
Revenues from external customers:
Revenues from external customers	158.4	208.6	316.6	411.2
Intersegment revenues:
Intersegment revenues	(158.4)	(208.6)	(316.6)	(411.2)
Depreciation and amortization expense:
Depreciation and amortization expense	6.5	6	12.7	12.1
Operating profit (loss)
Operating profit (loss)	(2.9)	3.8	(13.8)	(5)
Operating Segments [Member] | Railroad and Utility Products and Services [Member]
Revenues from external customers:
Revenues from external customers	170.9	148.2	329	277
Intersegment revenues:
Intersegment revenues	(170.9)	(148.2)	(329)	(277)
Depreciation and amortization expense:
Depreciation and amortization expense	6.4	3.7	10.5	6.5
Operating profit (loss)
Operating profit (loss)	15	12.8	30.4	23.9
Operating Segments [Member] | Performance Chemicals [Member]
Revenues from external customers:
Revenues from external customers	102.3	0	183.8	0
Intersegment revenues:
Intersegment revenues	(102.3)	0	(183.8)	0
Depreciation and amortization expense:
Depreciation and amortization expense	4.8	0	9.5	0
Operating profit (loss)
Operating profit (loss)	15.5	0	21.9	0
Intersegment [Member]
Revenues from external customers:
Revenues from external customers	(22.2)	(20.1)	(44.8)	(41.3)
Intersegment revenues:
Intersegment revenues	22.2	20.1	44.8	41.3
Intersegment [Member] | Carbon Materials and Chemicals [Member]
Revenues from external customers:
Revenues from external customers	(20)	(20.1)	(40.5)	(41.3)
Intersegment revenues:
Intersegment revenues	20	20.1	40.5	41.3
Intersegment [Member] | Performance Chemicals [Member]
Revenues from external customers:
Revenues from external customers	(2.2)	0	(4.3)	0
Intersegment revenues:
Intersegment revenues	2.2	0	4.3	0
Corporate, Non-Segment [Member]
Operating profit (loss)
Operating profit (loss)	$ (1.6)	$ (3.3)	$ (4.5)	$ (5.1)

Segment Information - Summary61

Segment Information - Summary of Results of Segment Operations (Parenthetical) (Detail) - USD ($) $ in Millions	Jan. 16, 2015	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenue from External Customer [Line Items]
Gain on sale of business		$ 0	$ 0	$ 3.2	$ 0
Impairment charges				2.7	4.7
Netherlands [Member]
Revenue from External Customer [Line Items]
Plant closure cost					10.8
China [Member]
Revenue from External Customer [Line Items]
Impairment charges					$ 4.7
United States [Member]
Revenue from External Customer [Line Items]
Impairment charges				2.5
North American Utility Pole Business [Member]
Revenue from External Customer [Line Items]
Gain on sale of business	$ 3.2
North American Utility Pole Business [Member] | Wood Treating Facility [Member] | United States [Member]
Revenue from External Customer [Line Items]
Gain on sale of business				3.2
Impairment charges				$ 2.5

Segment Information - Summary62

Segment Information - Summary of Tangible and Intangible Assets by Segments (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Segment assets:
Segment assets	$ 1,290.1	$ 1,293.9
Goodwill:
Goodwill	256.6	247.2
Carbon Materials and Chemicals [Member] | Operating Segments [Member]
Segment assets:
Segment assets	505	514.6
Goodwill:
Goodwill	68.3	65.5
Railroad and Utility Products and Services [Member] | Operating Segments [Member]
Segment assets:
Segment assets	267.7	275.2
Goodwill:
Goodwill	10.3	9.3
Performance Chemicals [Member] | Operating Segments [Member]
Segment assets:
Segment assets	479.3	469
Goodwill:
Goodwill	178	172.4
All Other [Member] | Operating Segments [Member]
Segment assets:
Segment assets	$ 38.1	$ 35.1

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income taxes as a percentage of pretax ordinary income	30.80%	65.00%	30.80%	64.30%
U.S. federal statutory rate	35.00%	35.00%	35.00%	35.00%
Taxes on foreign earnings	7.30%	28.20%	7.40%	27.60%
Nondeductible expenses	1.10%	1.00%	1.10%	1.00%
Uncertain tax positions	1.00%	1.20%	1.00%	1.20%
State taxes	1.00%	2.40%	1.10%	1.80%
Domestic manufacturing deduction		2.40%		2.30%
Net tax benefit included in income taxes, discrete items			$ 0.3	$ 5.7
Unrecognized tax benefits with impact on the effective tax rate	$ 5.5		5.5		$ 6
Unrecognized tax benefits	6.9		6.9		7.2
Accrued interest expense and penalties	$ 2.7		$ 2.7		$ 2.7

Inventories - Components of Inv

Inventories - Components of Inventories (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Raw materials	$ 166.6	$ 191.1
Work in process	16.1	2.6
Finished goods	98.2	103.6
Inventories, gross	280.9	297.3
Less revaluation to LIFO	57.5	56.1
Net	$ 223.4	$ 241.2

Property, Plant and Equipment -

Property, Plant and Equipment - Property, Plant and Equipment (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 758.5	$ 742.6
Less accumulated depreciation	466.6	442.9
Net	291.9	299.7
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	18.1	18.7
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	41.7	45.3
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 698.7	$ 678.6

Property, Plant and Equipment66

Property, Plant and Equipment - Additional Information (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Property, Plant and Equipment [Line Items]
Impairment charges	$ 2.7	$ 4.7
Railroad and Utility Products and Services [Member]
Property, Plant and Equipment [Line Items]
Impairment charges	$ 2.5
Koppers Carbon and Chemical Company Limited [Member]
Property, Plant and Equipment [Line Items]
Percentage of operations in Tangshan, China of owned subsidiary	60.00%

Pensions and Postretirement B67

Pensions and Postretirement Benefit Plans - Additional Information (Detail)	Jun. 30, 2015Plans
Postemployment Benefits [Abstract]
Number of domestic non-qualified defined benefit plans	3

Pensions and Post-retirement Be

Pensions and Post-retirement Benefit Plans - Components of Net Periodic Benefit Cost for Pension Plans and Other Benefit Plans (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Postemployment Benefits [Abstract]
Service cost	$ 0.5	$ 0.6	$ 1	$ 1.2
Interest cost	2.6	3.1	5.4	6
Expected return on plan assets	(3)	(3.5)	(6)	(7)
Amortization of prior service cost	0	(0.1)	(0.1)	(0.1)
Amortization of net loss	1.7	1	3.3	2
Net periodic benefit cost	1.8	1.1	3.6	2.1
Defined contribution plan expense	$ 2	$ 1.5	$ 2	$ 3.2

Pensions and Post-retirement 69

Pensions and Post-retirement Benefit Plans - Components of Net Periodic Benefit Cost for Pension Plans and Other Benefit Plans (Parenthetical) (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2015USD ($)
Postemployment Benefits [Abstract]
Reversal of 2014 discretionary 401k match accrual	$ 2.2

Debt - Schedule of Long-Term De

Debt - Schedule of Long-Term Debt Instruments (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Total debt	$ 794.2	$ 850.5
Less short term debt and current maturities of long-term debt	45.4	43.9
Long-term debt	748.8	806.6
Senior Notes [Member]
Debt Instrument [Line Items]
Less short term debt and current maturities of long-term debt	45.4	43.9
Long-term debt	$ 748.8	806.6
Senior Secured Credit Facilities [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	3.75%
Debt, Maturity	2,019
Total debt	$ 277.5	292.5
Senior Secured Credit Facilities [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	3.75%
Debt, Maturity	2,019
Total debt	$ 161.3	204.5
Committed Loan Facility Agreements [Member] | Construction Loans [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	5.81%
Debt, Maturity	2,018
Total debt	$ 58.1	56.5
7 7/8 Percent Senior Notes Due 2019 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	7.875%
Debt, Maturity	2,019
Total debt	$ 297.3	$ 297

Debt - Additional Information (

Debt - Additional Information (Detail) ¥ in Millions	Aug. 15, 2014USD ($)	Nov. 18, 2013USD ($)Installment	Dec. 01, 2009USD ($)	Jun. 30, 2015USD ($)	Nov. 18, 2013CNY (¥)Installment
Koppers Carbon and Chemical Company Limited [Member]
Debt Instrument [Line Items]
Percentage of owned subsidiary				60.00%
Senior Notes [Member]
Debt Instrument [Line Items]
Percentage of owned subsidiary			100.00%
Debt instrument, face amount			$ 300,000,000
Senior Secured Credit Facilities [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Revolving credit facility	$ 350,000,000
Revolving credit facility, current borrowing capacity	500,000,000
Senior secured term loan for acquiring Osmose	$ 300,000,000
Revolving credit facility, borrowing maturity date	Aug. 15, 2019
Initial interest rate	3.25%
Quarterly principal repayment obligations, interest rate	2.50%
Quarterly principal repayment obligations	$ 7,500,000
Debt instrument, unused borrowing capacity				$ 80,200,000
Letters of credit, amount outstanding				$ 61,600,000
Debt, Weighted Average Interest Rate				3.75%
Committed Loan Facility Agreements [Member] | Construction Loans [Member]
Debt Instrument [Line Items]
Percentage of non-controlling shareholders		25.00%			25.00%
Debt maturity date		Nov. 18, 2018
Number of installments for repayment of loans | Installment		6			6
Installment frequency for repayment of loans		6 months
Commencement period of debt repayment		2016-05
Debt, Weighted Average Interest Rate				5.81%
Committed Loan Facility Agreements [Member] | Construction Loans [Member] | Third Party Debt [Member]
Debt Instrument [Line Items]
Construction loan facility borrowing capacity | ¥					¥ 198.8
Committed Loan Facility Agreements [Member] | Construction Loans [Member] | Lender [Member] | Committed Credit Facility [Member]
Debt Instrument [Line Items]
Construction loan facility borrowing capacity | ¥					66.2
Committed Loan Facility Agreements [Member] | Construction Loans [Member] | Koppers Carbon and Chemical Company Limited [Member]
Debt Instrument [Line Items]
Percentage of owned subsidiary		75.00%
Construction loan facility borrowing capacity		$ 44,000,000			¥ 265
7 7/8 Percent Senior Notes Due 2019 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate				7.875%
Debt instrument, issuance date				Dec. 1, 2009
Debt instrument, offering price percentage			98.311%
Debt instrument, offering value			$ 294,900,000
Debt instrument, face amount			$ 300,000,000
Debt instrument, effective interest rate				8.125%
Debt instrument, redemption price percentage				103.938%
Frequency of interest payment on senior notes				Interest on the Senior Notes is payable semiannually on December 1 and June 1 each year

Asset Retirement Obligations -

Asset Retirement Obligations - Schedule of Changes in Carrying Values of Asset Retirement Obligations (Detail) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Asset Retirement Obligation Disclosure [Abstract]
Asset retirement obligation at beginning of year	$ 30.5	$ 23.2
Acquisition	0.8	0
Accretion expense	1.5	2.3
Revision in estimated cash flows	3.3	10.3
Cash expenditures	(3.5)	(4.6)
Currency translation	(0.4)	(0.7)
Balance at end of period	$ 32.2	$ 30.5

Deferred Revenue - Deferred Rev

Deferred Revenue - Deferred Revenue from Extended Product Warranty Liabilities (Detail) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Deferred Revenue Disclosure [Abstract]
Deferred revenue at beginning of year	$ 2.5	$ 3.2
Advance payment	29.6	0
Revenue earned	(0.2)	(0.7)
Deferred revenue at end of year	$ 31.9	$ 2.5

Deferred Revenue - Additional I

Deferred Revenue - Additional Information (Detail) $ in Millions	Jun. 30, 2015USD ($)
Deferred Revenue Disclosure [Abstract]
Deferred revenue	$ 30.7

Derivative Financial Instrume75

Derivative Financial Instruments - Additional Information (Detail) - Jun. 30, 2015 £ in Millions, NZD in Millions, CAD in Millions, $ in Millions	USD ($)	GBP (£)	CAD	NZD
Derivative [Line Items]
Maximum period hedged in cash flow hedge	30 months
Copper Swap Contracts [Member]
Derivative [Line Items]
Change in derivative financial instrument, net loss	$ 4.3
Unrealized losses, net of tax	3.3
Accrued Liabilities [Member] | Copper Swap Contracts [Member]
Derivative [Line Items]
Derivative fair value, net	(7.2)	£ 18.2
Forward Contracts [Member]
Derivative [Line Items]
Derivative fair value, net	1.3
Gross derivative assets	3.5
Gross derivative liability	2.2
Currency units outstanding	$ 88.1	£ 42.4	CAD 15.8	NZD 40.1

Commitments and Contingent Li76

Commitments and Contingent Liabilities - Additional Information (Detail) $ in Millions	Mar. 30, 2012USD ($)site	Jul. 31, 2004USD ($)	Jun. 30, 2015USD ($)siteCasesPartiesPlaintiffStatePlant	Dec. 31, 2014USD ($)CasesPlaintiff	Dec. 31, 2011USD ($)	Dec. 31, 2013USD ($)
Loss Contingencies [Line Items]
Number of states with new claims filed | State			2
Number of plaintiffs | Plaintiff			112	112
Number of cases | Cases			60	60
Environmental legal indemnification expense		$ 7
Sites listed on National Priorities List | site			1
Environmental remediation and regulation liability			$ 20.8	$ 7.8		$ 11.9
Environmental remediation reserve			0.3	0.8
Accrued liability for environmental matters, current			7.8	3.3
Portland Harbor and Newark Bay CERCLA sites [Member]
Loss Contingencies [Line Items]
Environmental contingencies reserve not provided by company			$ 0.6
Compensatory Damages [Member]
Loss Contingencies [Line Items]
Number of cases | Cases			60
Punitive Damages [Member]
Loss Contingencies [Line Items]
Number of cases | Cases			55
Indemnification Agreement [Member] | Beazer East [Member]
Loss Contingencies [Line Items]
Environmental remediation costs paid by others, per year				$ 13
Pennsylvania [Member]
Loss Contingencies [Line Items]
Number of cases | Cases			59
Tennessee [Member]
Loss Contingencies [Line Items]
Number of cases | Cases			1
Compensatory damages			$ 15
OREGON [Member] | Portland Harbor Cercla Site [Member]
Loss Contingencies [Line Items]
Number of potential responsible parties | Parties			80
Possible remedial alternatives | site	10
Remedial alternatives, lower range	$ 170
Remedial alternatives, higher range	$ 1,800
Australia [Member]
Loss Contingencies [Line Items]
Amount contributable by third party					$ 7.5
Environmental remediation expense			$ 3.9		$ 1.6
Environmental remediation reserve			$ 0.7
Arkansas [Member]
Loss Contingencies [Line Items]
Number of cases | Cases			3
United States [Member] | Environmental Protection Agency [Member]
Loss Contingencies [Line Items]
Environmental remediation and regulation liability			$ 0.2
United States [Member] | Osmose Holdings, Inc. [Member]
Loss Contingencies [Line Items]
Environmental legal indemnification expense			$ 5
Number of plant sites | Plant			2
Environmental remediation and regulation liability			$ 5.8
Amount contributable by third party			$ 0.3
United Kingdom And Australia [Member] | Osmose Holdings, Inc. [Member]
Loss Contingencies [Line Items]
Number of plant sites | Plant			3
Environmental remediation and regulation liability			$ 8.5
Amount contributable by third party			$ 1.6

Commitments and Contingent Li77

Commitments and Contingent Liabilities - Changes in Accrued Liability for Environmental Matters (Detail) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Balance at beginning of year	$ 7.8	$ 11.9
Expense	0.3	0.8
Reversal of reserves	(0.1)	(1.5)
Cash expenditures	(0.5)	(3.7)
Acquisition of Osmose Entities	13.6	0.7
Currency translation	(0.3)	(0.4)
Balance at end of period	$ 20.8	$ 7.8

Subsidiary Guarantor Informat78

Subsidiary Guarantor Information for Koppers Inc. Senior Notes - Additional Information (Detail) - USD ($)	Dec. 01, 2009	Jun. 30, 2015	Jun. 30, 2014
Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 300,000,000
Percent-owned material domestic subsidiaries	100.00%
Payment Guarantee by Subsidiaries for Senior Notes [Member]
Debt Instrument [Line Items]
Revolving credit facility		$ 500,000,000
Cash dividends paid		5,800,000	$ 12,600,000
Payment Guarantee by Subsidiaries for Senior Notes [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Restricted net assets		37,000,000
Payment Guarantee by Subsidiaries for Senior Notes [Member] | Term Loan Facility [Member]
Debt Instrument [Line Items]
Revolving credit facility		$ 300,000,000

Subsidiary Guarantor Informat79

Subsidiary Guarantor Information for Koppers Inc. Senior Notes - Condensed Consolidating Statement of Operations (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Condensed Statement of Income Captions [Line Items]
Net sales	$ 431.6	$ 356.8	$ 829.4	$ 688.2
Gain on sale of business	0	0	(3.2)	0
Selling, general and administrative	31.1	21.9	62.9	43.3
Operating (loss) profit	26	13.3	34	13.8
Other income (expense)	0.2	(0.3)	0.4	(0.1)
Income taxes	5.4	5.6	4.8	(0.4)
Income (loss) from continuing operations	7.9	0.8	3.7	0.7
Discontinued operations	0	(0.1)	0	(0.1)
Noncontrolling interests	(1.1)	(0.9)	(1.9)	(3.2)
Net income (loss) attributable to Koppers	9	1.6	5.6	3.8
Comprehensive (loss) income attributable to Koppers	12.2	4.1	(1.2)	9.4
Intersegment [Member]
Condensed Statement of Income Captions [Line Items]
Net sales	(22.2)	(20.1)	(44.8)	(41.3)
Senior Notes [Member]
Condensed Statement of Income Captions [Line Items]
Net sales	431.6	356.8	829.4	688.2
Cost of sales including depreciation and amortization	374.5	321.6	735.7	631.1
Gain on sale of business			(3.2)
Selling, general and administrative	31.1	21.9	62.9	43.3
Operating (loss) profit	26	13.3	34	13.8
Other income (expense)	0.2	(0.3)	0.4	(0.1)
Equity income (loss) of subsidiaries	0	0	0	0
Interest (income) expense	12.9	6.6	25.9	13.4
Income taxes	5.4	5.6	4.8	(0.4)
Income (loss) from continuing operations	7.9	0.8	3.7	0.7
Discontinued operations		(0.1)		(0.1)
Noncontrolling interests	(1.1)	(0.9)	(1.9)	(3.2)
Net income (loss) attributable to Koppers	9	1.6	5.6	3.8
Comprehensive (loss) income attributable to Koppers	12.4	4.1	(1.2)	9.4
Senior Notes [Member] | Intersegment [Member]
Condensed Statement of Income Captions [Line Items]
Net sales	(27.8)	(10.3)	(48.5)	(21.1)
Cost of sales including depreciation and amortization	(27.2)	(10.5)	(46.6)	(21.3)
Gain on sale of business			0
Selling, general and administrative	0	0	0	0
Operating (loss) profit	(0.6)	0.2	(1.9)	0.2
Other income (expense)	(0.6)	(1.1)	(1.1)	(2.1)
Equity income (loss) of subsidiaries	(36.9)	(10.5)	(47.7)	(7.1)
Interest (income) expense	(0.6)	(1.1)	(1.1)	(2.1)
Income taxes	0	0	0	0
Income (loss) from continuing operations	(37.5)	(10.3)	(49.6)	(6.9)
Discontinued operations		0		0
Noncontrolling interests	0	0	0	0
Net income (loss) attributable to Koppers	(37.5)	(10.3)	(49.6)	(6.9)
Comprehensive (loss) income attributable to Koppers	(46.2)	(14)	(28.4)	(24.7)
Senior Notes [Member] | Parent [Member]
Condensed Statement of Income Captions [Line Items]
Net sales	0	0	0	0
Cost of sales including depreciation and amortization	0	0	0	0
Gain on sale of business			0
Selling, general and administrative	0.6	0.5	1.1	1
Operating (loss) profit	(0.6)	(0.5)	(1.1)	(1)
Other income (expense)	0	0	0	0
Equity income (loss) of subsidiaries	9.1	2	6.1	4.5
Interest (income) expense	(0.1)	0	0	0
Income taxes	(0.4)	(0.1)	(0.6)	(0.3)
Income (loss) from continuing operations	9	1.6	5.6	3.8
Discontinued operations		0		0
Noncontrolling interests	0	0	0	0
Net income (loss) attributable to Koppers	9	1.6	5.6	3.8
Comprehensive (loss) income attributable to Koppers	12.4	4.1	(1.2)	9.4
Senior Notes [Member] | Koppers Inc. [Member]
Condensed Statement of Income Captions [Line Items]
Net sales	209.2	202.4	397	380
Cost of sales including depreciation and amortization	201	184	385.6	344.9
Gain on sale of business			(3.2)
Selling, general and administrative	10.4	14.3	22.2	27.8
Operating (loss) profit	(2.2)	4.1	(7.6)	7.3
Other income (expense)	2.9	0.1	3.1	0.1
Equity income (loss) of subsidiaries	22.3	7.3	31.9	9.6
Interest (income) expense	11.5	6.5	23.1	13.3
Income taxes	2.4	2.9	(1.8)	(0.8)
Income (loss) from continuing operations	9.1	2.1	6.1	4.5
Discontinued operations		0		0
Noncontrolling interests	0	0	0	0
Net income (loss) attributable to Koppers	9.1	2.1	6.1	4.5
Comprehensive (loss) income attributable to Koppers	12.3	4.5	(0.8)	10.1
Senior Notes [Member] | Domestic Guarantor Subsidiaries [Member]
Condensed Statement of Income Captions [Line Items]
Net sales	97	7.2	171.7	17.9
Cost of sales including depreciation and amortization	71.6	2.3	131.6	9.2
Gain on sale of business			0
Selling, general and administrative	9.6	0.3	18.6	0.6
Operating (loss) profit	15.8	4.6	21.5	8.1
Other income (expense)	1	0.9	2	1.8
Equity income (loss) of subsidiaries	5.5	1.2	9.7	(7)
Interest (income) expense	(0.1)	0	0	0
Income taxes	0.2	0.1	0.3	(5.9)
Income (loss) from continuing operations	22.2	6.6	32.9	8.8
Discontinued operations		0		0
Noncontrolling interests	0	0	0	0
Net income (loss) attributable to Koppers	22.2	6.6	32.9	8.8
Comprehensive (loss) income attributable to Koppers	24.9	8.7	24.6	13.6
Senior Notes [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Statement of Income Captions [Line Items]
Net sales	153.2	157.5	309.2	311.4
Cost of sales including depreciation and amortization	129.1	145.8	265.1	298.3
Gain on sale of business			0
Selling, general and administrative	10.5	6.8	21	13.9
Operating (loss) profit	13.6	4.9	23.1	(0.8)
Other income (expense)	(3.1)	(0.2)	(3.6)	0.1
Equity income (loss) of subsidiaries	0	0	0	0
Interest (income) expense	2.2	1.2	3.9	2.2
Income taxes	3.2	2.7	6.9	6.6
Income (loss) from continuing operations	5.1	0.8	8.7	(9.5)
Discontinued operations		(0.1)		(0.1)
Noncontrolling interests	(1.1)	(0.9)	(1.9)	(3.2)
Net income (loss) attributable to Koppers	6.2	1.6	10.6	(6.4)
Comprehensive (loss) income attributable to Koppers	$ 9	$ 0.8	$ 4.6	$ 1

Subsidiary Guarantor Informat80

Subsidiary Guarantor Information for Koppers Inc. Senior Notes - Condensed Consolidating Balance Sheet (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Assets
Cash and cash equivalents	$ 51.2	$ 51.1	$ 54.4	$ 82.2
Receivables, net	204.8	198.7
Inventories, net	223.4	241.2
Deferred tax assets	13.6	10.5
Other current assets	33.9	30.3
Total current assets	538.2	541.3
Equity investments	3.9	5
Property, plant and equipment, net	291.9	299.7
Goodwill	256.6	247.2
Intangible assets, net	165.2	167.7
Deferred tax assets	8.3	7.8
Other noncurrent assets	26	25.2
Total assets	1,290.1	1,293.9
LIABILITIES AND EQUITY
Accounts payable	170.8	120.6
Accrued liabilities	95.3	122.5
Short-term debt and current portion of long-term debt	45.4	43.9
Total current liabilities	311.5	292.1
Long-term debt	748.8	806.6
Other long-term liabilities	87.3	46.4
Total liabilities	1,211.2	1,210
Koppers shareholders' equity	70.4	70
Noncontrolling interests	8.5	13.9
Total liabilities and equity	1,290.1	1,293.9
Senior Notes [Member]
Assets
Cash and cash equivalents	51.2	51.1	54.4	82.2
Receivables, net	206.6	198.7
Affiliated receivables	0	0
Inventories, net	223.4	241.2
Deferred tax assets	13.6	10.5
Other current assets	43.4	39.8
Total current assets	538.2	541.3
Equity investments	3.9	5
Property, plant and equipment, net	291.9	299.7
Goodwill	256.6	247.2
Intangible assets, net	165.2	167.7
Deferred tax assets	8.3	7.8
Affiliated loan receivables	0	0
Other noncurrent assets	26	25.2
Total assets	1,290.1	1,293.9
LIABILITIES AND EQUITY
Accounts payable	170.8	120.6
Affiliated payables	0	0
Accrued liabilities	95.3	127.6
Short-term debt and current portion of long-term debt	45.4	43.9
Total current liabilities	311.5	292.1
Long-term debt	748.8	806.6
Affiliated debt	0	0
Other long-term liabilities	150.9	111.3
Total liabilities	1,211.2	1,210
Koppers shareholders' equity	70.4	70
Noncontrolling interests	8.5	13.9
Total liabilities and equity	1,290.1	1,293.9
Senior Notes [Member] | Intersegment [Member]
Assets
Cash and cash equivalents	0	0	0	0
Receivables, net	0	0
Affiliated receivables	(44.3)	(15.9)
Inventories, net	(2.7)	(1)
Deferred tax assets	0	0
Other current assets	0	0
Total current assets	(47)	(16.9)
Equity investments	(1,076.1)	(1,053.8)
Property, plant and equipment, net	0	0
Goodwill	0	0
Intangible assets, net	0	0
Deferred tax assets	0	0
Affiliated loan receivables	(310.5)	(293.4)
Other noncurrent assets	0	0
Total assets	(1,433.6)	(1,364.1)
LIABILITIES AND EQUITY
Accounts payable	0	0
Affiliated payables	(51.7)	(29.4)
Accrued liabilities	0	0
Short-term debt and current portion of long-term debt	0	0
Total current liabilities	(51.7)	(29.4)
Long-term debt	0	0
Affiliated debt	(310.5)	(293.4)
Other long-term liabilities	0	0
Total liabilities	(362.2)	(322.8)
Koppers shareholders' equity	(1,071.4)	(1,041.3)
Noncontrolling interests	0	0
Total liabilities and equity	(1,433.6)	(1,364.1)
Parent [Member] | Senior Notes [Member]
Assets
Cash and cash equivalents	0	0	0	0
Receivables, net	0	0
Affiliated receivables	0	0.8
Inventories, net	0	0
Deferred tax assets	0	0
Other current assets	0	0
Total current assets	0	0.8
Equity investments	69.9	74.5
Property, plant and equipment, net	0	0
Goodwill	0	0
Intangible assets, net	0	0
Deferred tax assets	0	0
Affiliated loan receivables	0	0
Other noncurrent assets	0	0
Total assets	69.9	75.3
LIABILITIES AND EQUITY
Accounts payable	0.1	0.1
Affiliated payables	0	0
Accrued liabilities	(0.6)	5.2
Short-term debt and current portion of long-term debt	0	0
Total current liabilities	(0.5)	5.3
Long-term debt	0	0
Affiliated debt	0	0
Other long-term liabilities	0	0
Total liabilities	(0.5)	5.3
Koppers shareholders' equity	70.4	70
Noncontrolling interests	0	0
Total liabilities and equity	69.9	75.3
Koppers Inc. [Member] | Senior Notes [Member]
Assets
Cash and cash equivalents	0.3	0	0	29.9
Receivables, net	83.3	75.7
Affiliated receivables	15.1	4.5
Inventories, net	98.8	108.8
Deferred tax assets	10.1	8
Other current assets	4.9	3
Total current assets	212.5	200
Equity investments	792.6	767.2
Property, plant and equipment, net	120.4	121.2
Goodwill	43.9	39.8
Intangible assets, net	9.4	2.2
Deferred tax assets	(3.4)	(1)
Affiliated loan receivables	30.9	40.5
Other noncurrent assets	19.1	19.1
Total assets	1,225.4	1,189
LIABILITIES AND EQUITY
Accounts payable	77.7	60.9
Affiliated payables	28.4	13.2
Accrued liabilities	33.8	37.9
Short-term debt and current portion of long-term debt	30.3	30
Total current liabilities	170.2	142
Long-term debt	706.1	764
Affiliated debt	209.6	145.5
Other long-term liabilities	68.2	68.6
Total liabilities	1,154.1	1,120.1
Koppers shareholders' equity	71.3	68.9
Noncontrolling interests	0	0
Total liabilities and equity	1,225.4	1,189
Domestic Guarantor Subsidiaries [Member] | Senior Notes [Member]
Assets
Cash and cash equivalents	0.5	0.9	0	0.1
Receivables, net	35.3	20
Affiliated receivables	10.7	9.3
Inventories, net	27.3	30.8
Deferred tax assets	(0.6)	1
Other current assets	4.1	2.2
Total current assets	77.3	64.2
Equity investments	215.1	213.5
Property, plant and equipment, net	42.6	43.1
Goodwill	152.9	149.9
Intangible assets, net	122.7	128.1
Deferred tax assets	5.1	1.1
Affiliated loan receivables	237.6	212
Other noncurrent assets	5	5.2
Total assets	858.3	817.1
LIABILITIES AND EQUITY
Accounts payable	28.1	9
Affiliated payables	8.2	2.7
Accrued liabilities	20.5	29.5
Short-term debt and current portion of long-term debt	0	0
Total current liabilities	56.8	41.2
Long-term debt	0	0
Affiliated debt	30.8	35.9
Other long-term liabilities	13	7.7
Total liabilities	100.6	84.8
Koppers shareholders' equity	757.7	732.3
Noncontrolling interests	0	0
Total liabilities and equity	858.3	817.1
Non-Guarantor Subsidiaries [Member] | Senior Notes [Member]
Assets
Cash and cash equivalents	50.4	50.2	$ 54.4	$ 52.2
Receivables, net	88	103
Affiliated receivables	18.5	1.3
Inventories, net	100	102.6
Deferred tax assets	4.1	1.5
Other current assets	34.4	34.6
Total current assets	295.4	293.2
Equity investments	2.4	3.6
Property, plant and equipment, net	128.9	135.4
Goodwill	59.8	57.5
Intangible assets, net	33.1	37.4
Deferred tax assets	6.6	7.7
Affiliated loan receivables	42	40.9
Other noncurrent assets	1.9	0.9
Total assets	570.1	576.6
LIABILITIES AND EQUITY
Accounts payable	64.9	50.6
Affiliated payables	15.1	13.5
Accrued liabilities	41.6	55
Short-term debt and current portion of long-term debt	15.1	13.9
Total current liabilities	136.7	133
Long-term debt	42.7	42.6
Affiliated debt	70.1	112
Other long-term liabilities	69.7	35
Total liabilities	319.2	322.6
Koppers shareholders' equity	242.4	240.1
Noncontrolling interests	8.5	13.9
Total liabilities and equity	$ 570.1	$ 576.6

Subsidiary Guarantor Informat81

Subsidiary Guarantor Information for Koppers Inc. Senior Notes - Condensed Consolidating Statement of Cash Flows (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Subsidiary, Sale of Stock [Line Items]
Cash provided by (used in) operating activities	$ 78.1	$ (8.7)
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions	(17.3)	(35.6)
Net cash proceeds (payments) from divestitures and asset sales	12.5	0
Net cash (used in) provided by investing activities	(20.1)	(65.2)
Cash provided by (used in) financing activities:
Deferred financing costs	(1)	0
Dividends paid	(8.7)	(10.2)
Net cash (used in) provided by financing activities	(66.6)	45.4
Effect of exchange rates on cash	8.7	0.7
Net increase (decrease) in cash and cash equivalents	0.1	(27.8)
Cash and cash equivalents at beginning of period	51.1	82.2
Cash and cash equivalents at end of period	51.2	54.4
Senior Notes [Member]
Subsidiary, Sale of Stock [Line Items]
Cash provided by (used in) operating activities	78.1	(8.7)
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions	(32.6)	(65.2)
(Loans to) repayments from affiliates	0	0
Net cash proceeds (payments) from divestitures and asset sales	12.5
Net cash (used in) provided by investing activities	(20.1)	(65.2)
Cash provided by (used in) financing activities:
Borrowings (repayments) of long-term debt	(56.6)	55.5
Borrowings (repayments) of affiliated debt	0	0
Deferred financing costs	(1)
Other financing activities	0	1.4
Dividends paid	(8.7)	(10.2)
Stock (repurchased) issued	(0.3)	(1.3)
Net cash (used in) provided by financing activities	(66.6)	45.4
Effect of exchange rates on cash	8.7	0.7
Net increase (decrease) in cash and cash equivalents	0.1	(27.8)
Cash and cash equivalents at beginning of period	51.1	82.2
Cash and cash equivalents at end of period	51.2	54.4
Senior Notes [Member] | Intersegment [Member]
Subsidiary, Sale of Stock [Line Items]
Cash provided by (used in) operating activities	(8.9)	(21.5)
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions	0	14.8
(Loans to) repayments from affiliates	17.4	45.2
Net cash proceeds (payments) from divestitures and asset sales	0
Net cash (used in) provided by investing activities	17.4	60
Cash provided by (used in) financing activities:
Borrowings (repayments) of long-term debt	0	0
Borrowings (repayments) of affiliated debt	(17.4)	(45.2)
Deferred financing costs	0
Other financing activities	0	0
Dividends paid	8.9	21.5
Stock (repurchased) issued	0	(14.8)
Net cash (used in) provided by financing activities	(8.5)	(38.5)
Effect of exchange rates on cash	0	0
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	0	0
Parent [Member] | Senior Notes [Member]
Subsidiary, Sale of Stock [Line Items]
Cash provided by (used in) operating activities	5.4	11.5
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions	0	0
(Loans to) repayments from affiliates	0	0
Net cash proceeds (payments) from divestitures and asset sales	0
Net cash (used in) provided by investing activities	0	0
Cash provided by (used in) financing activities:
Borrowings (repayments) of long-term debt	0	0
Borrowings (repayments) of affiliated debt	0	0
Deferred financing costs	0
Other financing activities	0	0
Dividends paid	(5.1)	(10.2)
Stock (repurchased) issued	(0.3)	(1.3)
Net cash (used in) provided by financing activities	(5.4)	(11.5)
Effect of exchange rates on cash	0	0
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	0	0
Koppers Inc. [Member] | Senior Notes [Member]
Subsidiary, Sale of Stock [Line Items]
Cash provided by (used in) operating activities	10.6	(19)
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions	(26.9)	(7.8)
(Loans to) repayments from affiliates	5.1	(21.5)
Net cash proceeds (payments) from divestitures and asset sales	12.2
Net cash (used in) provided by investing activities	(9.6)	(29.3)
Cash provided by (used in) financing activities:
Borrowings (repayments) of long-term debt	(57.9)	24.3
Borrowings (repayments) of affiliated debt	64	6.7
Deferred financing costs	(1)
Other financing activities	0	0
Dividends paid	(5.8)	(12.6)
Stock (repurchased) issued	0	0
Net cash (used in) provided by financing activities	(0.7)	18.4
Effect of exchange rates on cash	0	0
Net increase (decrease) in cash and cash equivalents	0.3	(29.9)
Cash and cash equivalents at beginning of period	0	29.9
Cash and cash equivalents at end of period	0.3	0
Domestic Guarantor Subsidiaries [Member] | Senior Notes [Member]
Subsidiary, Sale of Stock [Line Items]
Cash provided by (used in) operating activities	32.2	17.1
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions	(3.1)	(15)
(Loans to) repayments from affiliates	(21.4)	(23.7)
Net cash proceeds (payments) from divestitures and asset sales	0
Net cash (used in) provided by investing activities	(24.5)	(38.7)
Cash provided by (used in) financing activities:
Borrowings (repayments) of long-term debt	0.1	0
Borrowings (repayments) of affiliated debt	(5.1)	21.5
Deferred financing costs	0
Other financing activities	0	0
Dividends paid	(3.1)	0
Stock (repurchased) issued	0	0
Net cash (used in) provided by financing activities	(8.1)	21.5
Effect of exchange rates on cash	0	0
Net increase (decrease) in cash and cash equivalents	(0.4)	(0.1)
Cash and cash equivalents at beginning of period	0.9	0.1
Cash and cash equivalents at end of period	0.5	0
Non-Guarantor Subsidiaries [Member] | Senior Notes [Member]
Subsidiary, Sale of Stock [Line Items]
Cash provided by (used in) operating activities	38.8	3.2
Cash provided by (used in) investing activities:
Capital expenditures and acquisitions	(2.6)	(57.2)
(Loans to) repayments from affiliates	(1.1)	0
Net cash proceeds (payments) from divestitures and asset sales	0.3
Net cash (used in) provided by investing activities	(3.4)	(57.2)
Cash provided by (used in) financing activities:
Borrowings (repayments) of long-term debt	1.2	31.2
Borrowings (repayments) of affiliated debt	(41.5)	17
Deferred financing costs	0
Other financing activities	0	1.4
Dividends paid	(3.6)	(8.9)
Stock (repurchased) issued	0	14.8
Net cash (used in) provided by financing activities	(43.9)	55.5
Effect of exchange rates on cash	8.7	0.7
Net increase (decrease) in cash and cash equivalents	0.2	2.2
Cash and cash equivalents at beginning of period	50.2	52.2
Cash and cash equivalents at end of period	$ 50.4	$ 54.4

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Loan to related party	$ 9,500,000	$ 9,500,000
Equity Method Investee [Member]
Related Party Transaction [Line Items]
Loan to related party	$ 9,500,000
Ownership percentage	30.00%
Carrying value of equity investment recoverable	$ 2,000,000
Provision for loans	0
Equity Method Investee [Member] | Loan [Member]
Related Party Transaction [Line Items]
Installment payment defaulted	$ 1,600,000