GCP Applied (GCP) 10-Q 6 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 31, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	GCP Applied Technologies Inc.
Entity Central Index Key	1,644,440
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		72,166,406
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3

Consolidated Statements of Oper

Consolidated Statements of Operations (unaudited) - USD ($) shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Net sales		$ 296.3	$ 282.4	$ 849.3	$ 794.9
Cost of goods sold		185.9	175.9	539.7	488.1
Gross profit		110.4	106.5	309.6	306.8
Selling, general and administrative expenses		67.3	76.3	219.8	221.9
Research and development expenses		5.2	5.2	15.4	15.2
Interest expense and related financing costs		5.9	21.6	86.4	56.1
Repositioning expenses		3.7	1.1	5.8	6.8
Restructuring expenses and asset impairments		14.3	2.1	13.2	13
Loss in Venezuela		0	36.7	0	38.3
Other income, net		(0.9)	(4)	(11.3)	(6.6)
Total costs and expenses		95.5	139	329.3	344.7
Income (loss) from continuing operations before income taxes		14.9	(32.5)	(19.7)	(37.9)
(Provision for) benefit from income taxes		(7.6)	14.5	(15.8)	(3.7)
Income (loss) income from continuing operations		7.3	(18)	(35.5)	(41.6)
Income from discontinued operations, net of income taxes		18.2	677.3	26.7	679.4
Net income (loss)		25.5	659.3	(8.8)	637.8
Less: Net income attributable to noncontrolling interests		(0.1)	(0.1)	(0.3)	(0.2)
Net income (loss) attributable to GCP shareholders		25.4	659.2	(9.1)	637.6
Amounts Attributable to GCP Shareholders:
Income (loss) from continuing operations attributable to GCP shareholders		7.2	(18.1)	(35.8)	(41.8)
Income from discontinued operations, net of income taxes		$ 18.2	$ 677.3	$ 26.7	$ 679.4
Basic earnings (loss) per share:
Income (loss) from continuing operations attributable to GCP shareholders		$ 0.10	$ (0.25)	$ (0.50)	$ (0.59)
Income from discontinued operations, net of income taxes (in dollars per share)		0.25	9.46	0.37	9.54
Net income (loss) attributable to GCP shareholders (in dollars per share)	[1]	$ 0.35	$ 9.21	$ (0.13)	$ 8.96
Weighted average number of basic shares		72.2	71.6	72.1	71.2
Diluted earnings (loss) per share:
Income (loss) from continuing operations attributable to GCP shareholders (in dollars per share)	[2]	$ 0.10	$ (0.25)	$ (0.50)	$ (0.59)
Income from discontinued operations, net of income taxes (in dollars per share)	[2]	0.25	9.46	0.37	9.54
Net income (loss) attributable to GCP shareholders (in dollars per share)	[1],[2]	$ 0.35	$ 9.21	$ (0.13)	$ 8.96
Weighted average number of diluted shares	[2]	72.7	71.6	72.1	71.2
[1]	Amounts may not sum due to rounding.
[2]	Dilutive effect only applicable to periods where there is income from continuing operations.

Consolidated Balance Sheets (un

Consolidated Balance Sheets (unaudited) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Current Assets
Cash and cash equivalents	$ 301	$ 721.5
Trade accounts receivable (including allowances of $5.9 million and $5.7 million, respectively)	213.1	217.1
Inventories, net	115.9	106.3
Other current assets	47.2	48.6
Current assets held for sale	3.1	19.7
Total Current Assets	680.3	1,113.2
Properties and equipment, net	220.2	216.6
Goodwill	210.1	198.2
Technology and other intangible assets, net	91.9	91.8
Deferred income taxes	29.1	30.2
Overfunded defined benefit pension plans	26.1	26.4
Other assets	31.7	23.8
Non-current assets held for sale	0.9	2.8
Total Assets	1,290.3	1,703
Current Liabilities
Debt payable within one year	10.9	24
Accounts payable	125.8	134.8
Other current liabilities	156.8	316.2
Current liabilities held for sale	1.2	7.8
Total Current Liabilities	294.7	482.8
Debt payable after one year	346.7	520.3
Income taxes payable	49.2	58.3
Deferred income taxes	15.4	14.7
Unrecognized tax benefits	43.2	42.4
Underfunded and unfunded defined benefit pension plans	56.6	57.1
Other liabilities	19.5	35.1
Non-current liabilities held for sale	0.3	0.3
Total Liabilities	825.6	1,211
Commitments and Contingencies - Note 8
Stockholders' Equity
Common stock issued, par value $0.01; 300,000,000 shares authorized; outstanding: 72,161,545 and 71,754,344, respectively	0.7	0.7
Paid-in capital	40.4	29.9
Accumulated earnings	539.6	548.7
Accumulated other comprehensive loss	(113.3)	(85.7)
Treasury stock	(4.7)	(3.4)
Total GCP's Shareholders' Equity	462.7	490.2
Noncontrolling interests	2	1.8
Total Stockholders' Equity	464.7	492
Total Liabilities and Stockholders' Equity	$ 1,290.3	$ 1,703

Consolidated Balance Sheets (_2

Consolidated Balance Sheets (unaudited) (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Trade accounts receivable, allowance	$ 5.9	$ 5.7
Common stock issued, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, number of shares authorized	300,000,000	300,000,000
Common stock, number of shares outstanding	72,161,545	71,754,344

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) (unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 25.5	$ 659.3	$ (8.8)	$ 637.8
Other comprehensive (loss) income:
Defined benefit pension and other postretirement plans, net of income taxes	0.2	(0.3)	(0.4)	(0.3)
Currency translation adjustments	(9.1)	46.2	(27.3)	63
Gain (loss) from hedging activities, net of income taxes	0	0.5	0.1	(0.1)
Total other comprehensive (loss) income	(8.9)	46.4	(27.6)	62.6
Comprehensive income (loss)	16.6	705.7	(36.4)	700.4
Less: Comprehensive income attributable to noncontrolling interests	(0.1)	(0.1)	(0.3)	(0.2)
Comprehensive income (loss) attributable to GCP shareholders	$ 16.5	$ 705.6	$ (36.7)	$ 700.2

Consolidated Statements of Equi

Consolidated Statements of Equity (Deficit) (unaudited) - USD ($) shares in Thousands, $ in Millions		Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Accumulated Earnings / (Deficit)	Accumulated Other Comprehensive Loss	Noncontrolling Interests
Beginning balance (in shares) at Dec. 31, 2016			71,200	100
Beginning balance at Dec. 31, 2016		$ (139)	$ 0.7	$ (2.1)	$ 11	$ (4.7)	$ (147.6)	$ 3.7
Increase (Decrease) in Stockholders' Equity
Net income (loss)		637.8				637.6		0.2
Issuance of common stock in connection with stock plans (in shares)			100
Issuance of common stock in connection with stock plans		0
Share-based compensation		7.5			7.5
Exercise of stock options (in shares)			400
Exercise of stock options		6.6			6.6
Share repurchases (in shares)				37
Share repurchases	[1]	(1)		$ (1)
Other comprehensive income (loss)		62.6					62.6
Dividends and other changes in noncontrolling interest		(2.3)						(2.3)
Ending balance (in shares) at Sep. 30, 2017			71,700	100
Ending balance at Sep. 30, 2017		572.2	$ 0.7	$ (3.1)	25.1	632.9	(85)	1.6
Beginning balance (in shares) at Dec. 31, 2017			71,900	100
Beginning balance at Dec. 31, 2017		492	$ 0.7	$ (3.4)	29.9	548.7	(85.7)	1.8
Increase (Decrease) in Stockholders' Equity
Net income (loss)		(8.8)				(9.1)		0.3
Issuance of common stock in connection with stock plans (in shares)			100
Issuance of common stock in connection with stock plans		0
Share-based compensation		5.3			5.3
Exercise of stock options (in shares)			400
Exercise of stock options		5.2			5.2
Share repurchases (in shares)	[1]			100
Share repurchases	[1]	(1.3)		$ (1.3)
Other comprehensive income (loss)		(27.6)					(27.6)
Dividends and other changes in noncontrolling interest		(0.1)						(0.1)
Ending balance (in shares) at Sep. 30, 2018			72,400	200
Ending balance at Sep. 30, 2018		$ 464.7	$ 0.7	$ (4.7)	$ 40.4	$ 539.6	$ (113.3)	$ 2
[1]	During the nine months ended September 30, 2018 and 2017, GCP repurchased approximately 45,000 shares and 37,000 shares of Company common stock for $1.3 million and $1.0 million, respectively, in connection with its equity compensation programs.

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
OPERATING ACTIVITIES
Net income (loss)	$ (8,800,000)	$ 637,800,000
Less: Income from discontinued operations	26,700,000	679,400,000
Loss from continuing operations	(35,500,000)	(41,600,000)
Reconciliation to net cash (used in) provided by operating activities:
Depreciation and amortization	31,300,000	26,900,000
Amortization of debt discount and financing costs	1,200,000	2,200,000
Stock-based compensation expense	4,600,000	7,100,000
Unrealized loss on foreign currency	0	700,000
Gain on termination and curtailment of pension and other postretirement benefit plans	(100,000)	(5,800,000)
Currency and other losses in Venezuela	0	40,100,000
Deferred income taxes	(2,500,000)	(5,600,000)
Loss on debt refinancing	59,800,000	0
Gain on disposal of property and equipment	(1,100,000)	(600,000)
Loss on sale of product line	0	2,100,000
Changes in assets and liabilities, excluding effect of currency translation:
Trade accounts receivable	(6,300,000)	(40,000,000)
Inventories	(13,100,000)	(13,300,000)
Accounts payable	(2,300,000)	18,800,000
Pension assets and liabilities, net	0	7,200,000
Other assets and liabilities, net	(6,400,000)	(7,300,000)
Net cash provided by (used in) operating activities from continuing operations	29,600,000	(9,100,000)
Net cash used in operating activities from discontinued operations	(130,400,000)	(15,300,000)
Net cash used in operating activities	(100,800,000)	(24,400,000)
INVESTING ACTIVITIES
Capital expenditures	(40,700,000)	(32,400,000)
Businesses acquired, net of cash acquired	(29,700,000)	(87,700,000)
Proceeds from sale of product line	0	2,900,000
Other investing activities	(2,900,000)	2,400,000
Net cash used in investing activities from continuing operations	(73,300,000)	(114,800,000)
Net cash provided by investing activities from discontinued operations	100,000	1,038,300,000
Net cash (used in) provided by investing activities	(73,200,000)	923,500,000
FINANCING ACTIVITIES
Borrowings under credit arrangements	54,600,000	120,000,000
Repayments under credit arrangements	(66,400,000)	(416,600,000)
Proceeds from issuance of long term note obligations	350,000,000	0
Repayments of long term note obligations	(578,300,000)	0
Cash paid for debt financing costs	(6,900,000)	0
Share repurchases	(1,300,000)	(1,000,000)
Proceeds from exercise of stock options	5,200,000	6,100,000
Noncontrolling interest dividend	(100,000)	(2,000,000)
Other financing activities	(700,000)	0
Net cash used in financing activities from continuing operations	(243,900,000)	(293,500,000)
Net cash provided by financing activities from discontinued operations	0	1,100,000
Net cash used in financing activities	(243,900,000)	(292,400,000)
Effect of currency exchange rate changes on cash and cash equivalents	(2,600,000)	1,400,000
(Decrease) increase in cash and cash equivalents	(420,500,000)	608,100,000
Cash and cash equivalents, beginning of period	721,500,000	163,300,000
Cash and cash equivalents, end of period	$ 301,000,000	$ 771,400,000

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies	Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies GCP is engaged in the production and sale of specialty construction chemicals and specialty building materials through two operating segments. Specialty Construction Chemicals ("SCC") manufactures and markets concrete admixtures and cement additives. Specialty Building Materials ("SBM") manufactures and markets sheet and liquid membrane systems that protect structures from water, air and vapor penetration, fireproofing and other products designed to protect the building envelope. On July 3, 2017 (the "Closing Date"), GCP completed the sale of its Darex Packaging Technologies ("Darex") business to Henkel AG & Co. KGaA (“Henkel”) for $1.06 billion in cash. As discussed further below under "Discontinued Operations," the results of operations for Darex have been excluded from GCP's continuing operations and segment results for all periods presented. Basis of Presentation The accompanying unaudited Consolidated Financial Statements are presented on a consolidated basis and include all of the accounts and operations of GCP and its majority-owned subsidiaries, except as noted below with respect to the Company's Venezuela subsidiary. The financial statements reflect the financial position, results of operations and cash flows of GCP in accordance with generally accepted accounting principles in the United States of America ("GAAP") and the instructions to Form 10-Q and Article 10 of SEC Regulation S-X for interim financial information. The interim financial statements presented herein are unaudited and should be read in conjunction with the audited Consolidated Financial Statements and notes thereto contained in GCP's Annual Report on Form 10-K filed with the SEC for the year ended December 31, 2017 (the "2017 Annual Report on Form 10-K"). The accompanying Consolidated Balance Sheet as of December 31, 2017 was derived from the audited annual consolidated financial statements as of the period then ended. Certain information and footnote disclosures typically included in GCP's annual consolidated financial statements have been condensed or omitted. The accompanying unaudited financial statements reflect all adjustments that, in the opinion of management, are necessary for a fair statement of the results of the interim periods presented. All such adjustments are of a normal recurring nature except for the impacts of adopting new accounting standards discussed below. All significant intercompany accounts and transactions have been eliminated. The results of operations for the three and nine-months period ended September 30, 2018 are not necessarily indicative of the results of operations for the year ending December 31, 2018. Discontinued Operations As noted above, on July 3, 2017, the Company completed the sale of Darex to Henkel. In conjunction with this transaction and applicable GAAP, the assets and liabilities related to Darex in the applicable delayed close countries have been reclassified and reflected as "held for sale" in the accompanying unaudited Consolidated Balance Sheets as of September 30, 2018 and December 31, 2017, as discussed further in Note 15, "Discontinued Operations". Additionally, Darex results of operations and cash flows have been reclassified and reflected as "discontinued operations" in the accompanying unaudited Consolidated Statements of Operations and accompanying unaudited Consolidated Statements of Cash Flows for all periods presented. As of December 31, 2017, a liability of $55.1 million and $13.6 million , respectively, related to the consideration received by GCP for the delayed closings was recognized in “Other current liabilities” and “Other liabilities." During the nine months ended September 30, 2018 , GCP reduced the liability by $55.1 million which consisted primarily of the sale proceeds received on July 3, 2017 for the delayed closings in Argentina, Colombia, Peru, and China completed during the period then ended. The remaining liability of $13.1 million and $0.5 million , respectively, for the consideration received on the closing date related to the remaining delayed closing countries is recorded in “Other current liabilities” and "Other liabilities" as of September 30, 2018 . Unless otherwise noted, the information throughout the Notes to the accompanying unaudited Consolidated Financial Statements pertains only to the continuing operations of GCP. Please refer to Note 15, "Discontinued Operations" for further discussion of discontinued operations. Deconsolidation of Venezuelan Operations Prior to July 3, 2017, the Company included the results of its Venezuelan operations (“GCP Venezuela”) in the Consolidated Financial Statements using the consolidation method of accounting. Venezuelan exchange control regulations have resulted in an other-than-temporary lack of exchangeability between the Venezuelan bolivar and U.S. dollar, and have restricted GCP Venezuela’s ability to pay dividends and meet obligations denominated in U.S. dollars. These exchange regulations, combined with other regulations, have constrained availability of raw materials and have significantly limited GCP Venezuela’s ability to maintain normal production. As a result of these conditions, combined with the loss of scale in Venezuela resulting from the sale of the Company’s Darex-related operations and assets in Venezuela, GCP has deconsolidated its Venezuelan operations as of July 3, 2017 in accordance with provisions of Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") 810, Consolidation. During the three months ended September 30, 2017, GCP recognized a pre-tax loss of $36.7 million which was $23.8 million after tax. Such loss is primarily related to unfavorable cumulative translation adjustments of $33.4 million associated with the Venezuelan business and presented as a “Loss in Venezuela” in the accompanying unaudited Consolidated Statements of Operations during the three and nine months ended September 30, 2017. Subsequent to July 3, 2017, the Company began accounting for GCP Venezuela using the cost method of accounting in accordance with which the Company’s financial results do not include the operating results of GCP Venezuela. The Company records cash and recognizes income from its Venezuelan operations in the accompanying unaudited Consolidated Financial Statements to the extent GCP is paid for inventory sold to or dividends are received from GCP Venezuela. The remaining investment on the Company's accompanying unaudited Consolidated Balance Sheets as of September 30, 2018 and December 31, 2017 is immaterial. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amount of assets and liabilities and disclosure of contingent assets and liabilities at the date of the unaudited Consolidated Financial Statements, and the reported amounts of revenues and expenses for the periods presented. Actual amounts could differ from those estimates, and the differences could be material. Changes in estimates are recorded in the period identified. GCP's accounting measurements that are most affected by management's estimates of future events are disclosed in its 2017 Annual Report on Form 10-K. There have been no significant changes to management's assumptions and estimates underlying those measurements as reported in these interim financial statements, except as discussed in Note 5, "Income Taxes". Reclassifications Certain amounts in prior period financial statements have been reclassified to conform to the current period presentation. Such reclassifications have not materially affected previously reported amounts. Revision of Prior Period Financial Statements During the nine months ended September 30, 2018 GCP identified an error related to the presentation of the effect of currency exchange rate changes on cash and cash equivalents in its unaudited Consolidated Statements of Cash Flows filed in its Form 10-Q for the quarterly period ended September 30, 2017 and Consolidated Statements of Cash Flows in its 2017 Annual Report on Form 10-K for the year ended December 31, 2017. The correction of this error resulted in a reclassification between “cash provided by (used in) operating activities from continuing operations” and “effect of currency exchange rate changes on cash and cash equivalents” on the Consolidated Statements of Cash Flows filed during these periods. There was no impact on the Consolidated Statements of Operations, Consolidated Statements of Comprehensive Income, Consolidated Balance Sheets, or Consolidated Statements of Stockholders’ Equity during these periods as a result of these errors. The Company considered the guidance in ASC Topic 250, Accounting Changes and Error Corrections , ASC Topic 250-10-S99-1, Assessing Materiality , and ASC Topic 250-10-S99-2, Considering the Effects of Prior Year Misstatements when Quantifying Misstatements in Current Year Financial Statements in evaluating whether the Company’s previously issued consolidated financial statements were materially misstated. The Company concluded this error was not material individually or in the aggregate to the financial statements presented during any of the prior reporting periods, and therefore, amendments of previously filed Form 10-Q for the quarterly period ended September 30, 2017 and the 2017 Annual Report on Form 10-K for the year ended December 31, 2017 were not required. The revisions for these corrections to the applicable prior periods are reflected in the financial information herein and will be reflected in future filings containing such financial information. The following table summarizes the effects of the error on the interim and annual prior-period financial statements: Nine Months Ended, Year Ended, September 30, 2017 December 31, 2017 (in millions) As Previously Reported Adjustment As Revised As Previously Reported Adjustment As Revised CASH FLOWS FROM OPERATING ACTIVITIES: Net cash (used in) provided by operating activities from continuing operations $ (11.7 ) $ 2.6 $ (9.1 ) $ (5.4 ) $ 4.4 $ (1.0 ) Effect on currency exchange rate changes on cash and cash equivalents 4.0 (2.6 ) 1.4 6.4 (4.4 ) 2.0 Income Tax As a global enterprise, GCP is subject to a complex array of tax regulations and is required to make assessments of applicable tax laws and judgments in estimating its ultimate income tax liability. Please refer to Note 5, "Income Taxes," for further discussion regarding estimates used in accounting for income tax matters, including unrecognized tax benefits. Currency Translation Assets and liabilities of foreign subsidiaries (other than those located in countries with highly inflationary economies) are translated into U.S. dollars at current exchange rates, while revenues, costs and expenses are translated at average exchange rates during each reporting period. The resulting currency translation adjustments are included in "Accumulated other comprehensive loss" in the accompanying unaudited Consolidated Balance Sheets. The financial statements of any subsidiaries located in countries with highly inflationary economies are remeasured as if the functional currency were the U.S. dollar. Translation adjustments recognized as a result of such remeasurements are reflected in the results of operations in the unaudited Consolidated Statements of Operations. As of July 3, 2017, GCP deconsolidated its Venezuelan operations and, as a result, the Company's financial results no longer include the operations of GCP Venezuela, including currency translation adjustments, beyond that date. As of June 30, 2018, GCP concluded that Argentina is a highly inflationary economy since the three-year cumulative inflation rates commonly used to evaluate Argentina’s inflation currently exceed 100% . As a result, GCP began accounting for its operations in Argentina as a highly inflationary economy during the three months ended September 30, 2018. Effective July 1, 2018, the functional currency of the Company's subsidiary operating in Argentina became the U.S. dollar and all remeasurement adjustments after the effective date are reflected in GCP's results operations in the accompanying unaudited Consolidated Statements of Operations. During the three months ended September 30, 2018, the Company incurred losses of $1.1 million related to the remeasurement of these monetary net assets which are included in "Other income, net" in the accompanying unaudited Consolidated Statements of Operations. Net sales generated by the Argentina subsidiary were not material to the Company's consolidated net sales during the three and nine months ended September 30, 2018. Monetary net assets denominated in local currency within the Company's Argentina subsidiary were not material to GCP's consolidated total assets as of September 30, 2018. Contract Assets and Contract Liabilities Contract assets consist of unbilled amounts typically resulting from sales under long-term contracts when the revenue recognized exceeds the amount billed to the customer. Contract liabilities consist of advance payments and billings for revenue not meeting the criteria to be recognized and/or in excess of costs incurred. The Company’s contract assets and liabilities resulting from its contracts in the SCC or SBM operating segments were not material as of September 30, 2018 and December 31, 2017. Additionally, the amounts recorded in the accompanying unaudited Statements of Operations for the three and nine months ended September 30, 2018 related to changes in the contract assets and liabilities during the periods were immaterial. Trade accounts receivable include amounts billed and currently due from customers. The amounts due are stated at their net estimated realizable value. The Company maintains an allowance for doubtful accounts to provide for the estimated amount of receivables that will not be collected. The allowance is based upon an assessment of customer creditworthiness, historical payment experience, the age of outstanding receivables and collateral to the extent applicable. As of September 30, 2018 and December 31, 2017, the Company’s total trade accounts receivable balance was $213.1 million and $217.1 million , respectively, of which $5.0 million and $5.6 million , respectively, was related to trade accounts receivable associated with rental revenue generated from leases within certain SCC contracts and accounted for within the provisions of ASC Topic 840, Leases ("Topic 840"). Costs to Obtain a Contract GCP pays external sales agents certain commissions based on actual customer sales and it has determined that such amounts represent incremental costs incurred in obtaining such customer contracts. The performance obligations associated with these costs are satisfied at a point in time and accordingly the amortization period of such costs is less than one year. The Company expenses these costs as incurred in accordance with the practical expedient that allows for such treatment, as prescribed by ASC Topic 340-40, Costs to obtain or fulfill a contract . Recently Issued Accounting Standards Leases In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) , which is intended to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. In accordance with provisions of Topic 842, a lessee will be required to recognize in the statement of financial position a lease liability related to making lease payments and a right-of-use asset representing its right to use the underlying asset for the lease term, including optional payments that are reasonably certain to occur. In July 2018, the FASB issued two amendments to ASU 2016-02. The first amendment clarifies the application of certain aspects of ASU 2016-02 related to: (i) the rate implicit in the lease, (ii) impairment of the net investment in the lease, (iii) lessee reassessment of lease classification, (iv) lessor reassessment of lease term and purchase options, (v) variable payments that depend on an index or rate and (vi) certain transition adjustments, among other things. The second amendment includes a transition option allowing entities to forgo the application of ASU 2016-02 in the comparative periods presented in the financial statements during the year of adoption. Additionally, the amendment includes a practical expedient which provides lessors with an option to not separate non-lease components from the associated lease components when certain criteria are met and requires lessors to account for the combined component in accordance with provisions of ASC Topic 606 if the associated non-lease components are the predominant components in the arrangement. The guidance and the related amendments are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, with early adoption being permitted. GCP will adopt Topic 842 during the first quarter of 2019. As of September 30, 2018, GCP initiated the evaluation of the potential impact of adopting Topic 842 on its financial position, results of operations and related disclosures, but has not yet completed such assessment or determined whether it will elect the practical expedients upon adoption or the transition option allowing companies to forgo the application of Topic 842 in the comparative periods presented in its financial statements during the year of adoption. GCP has established a steering committee, a project plan and an implementation team which will analyze GCP's current contracts portfolio to determine the impact of adopting Topic 842 on the Company's financial position, results of operations and related disclosures. The implementation team is also responsible for evaluating and designing the necessary changes to the Company’s business processes, policies, systems and controls to support recognition and disclosure under the new guidance. During the three months ended September 30, 2018, GCP launched a comprehensive data collection initiative related to the population of arrangements containing leases and made a significant progress on collecting a portion of such data as of September 30, 2018. The Company also began the initial assessment of its lease contracts to determine the impact of adopting Topic 842 on its financial position, results of operations and related disclosures, but has not reached final conclusions related to such assessment as of September 30, 2018. Additionally, the Company completed a third party vendor selection process related to the lease accounting and management software solution to facilitate the adoption of Topic 842 and streamline the related accounting, contract tracking and disclosure reporting processes. Other new pronouncements issued but not effective until after September 30, 2018 are not expected to have a material impact on the Company's financial position, results of operations or liquidity. Recently Adopted Accounting Standards Revenue from Contracts with Customers In May 2014, the FASB issued Accounting Standards Update ("ASU") 2014-09, Revenue from Contracts with Customers (Topic 606). This update is intended to remove inconsistencies and weaknesses in revenue requirements; provide a more robust framework for addressing revenue issues; improve comparability of revenue recognition practices across entities, industries, jurisdictions and capital markets; provide more useful information to users of financial statements through improved disclosure requirements; and simplify the preparation of financial statements by reducing the number of requirements to which an entity must refer. The revised standard allows for two methods of adoption: (a) full retrospective adoption, in accordance with which the standard is applied to all periods presented, or (b) modified retrospective adoption, in accordance with which the cumulative effect of applying the new standard is recognized as an adjustment to the opening retained earnings balance. GCP has adopted Topic 606 effective January 1, 2018 using the modified retrospective approach. Under this transition method, GCP has elected to apply the guidance to all open contracts that are not completed or that are active as of January 1, 2018, and has elected not to retrospectively restate any of its contracts for modifications that occurred prior to the date of adoption of Topic 606. Accordingly, such modifications are reflected in the amounts reported for satisfied and unsatisfied performance obligations, transaction price of such performance obligations, and allocations of the transaction price among contract components, as of the date of the initial application. The impact of applying this practical expedient is immaterial to the Company’s accompanying unaudited Consolidated Financial Statements. The impact of the adoption of Topic 606 on the Company's three and nine months ended September 30, 2018 net sales, income (loss) from continuing operations before income taxes, and income (loss) from continuing operations was immaterial. The cumulative impact on the Company's retained earnings at January 1, 2018 was also not material. Such impact is disclosed in Note 2, "Revenue from Contracts with Customers." Stock Compensation In May 2017, the FASB issued ASU 2017-09, Compensation—Stock Compensation (Topic 718), which provides guidance related to the changes to the terms or conditions of a share-based payment award that require an application of modification accounting pursuant to Topic 718. GCP adopted the standard effective January 1, 2018; such adoption did not have a material impact on its financial position as of September 30, 2018 and results of operations for the three and nine months ended September 30, 2018. Statement of Cash Flows In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Payments, which addresses a number of specific cash flow presentation issues with the objective of reducing existing diversity in practice. GCP adopted the standard effective January 1, 2018 and classified within the cash flows from financing activities a $53.3 million payment related to the redemption premium on the extinguishment of its 9.5% Senior Notes, consistent with the provisions of the guidance. Such payment was included in "Repayments of long term note obligations" in the accompanying unaudited Consolidated Statements of Cash Flows. Please refer to Note 4, "Debt and Other Borrowings" for further discussion of this transaction. There was no other material impact on the Company's unaudited Consolidated Statements of Cash Flows for the nine months ended September 30, 2018 as a result of the standard adoption. Income Taxes In October 2016, the FASB issued ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory . This ASU requires recognition of the current and deferred income tax effects of an intra-entity asset transfer, other than inventory, when the transfer occurs, as opposed to current GAAP, which requires companies to defer the income tax effects until the asset has been sold to an outside party. GCP adopted the standard effective January 1, 2018. It did not have a material impact on the Company's financial position as of September 30, 2018 and results of operations for the three and nine months ended September 30, 2018. Other During the three and nine months ended September 30, 2018 , except as discussed above, there were no material changes to the Company's significant accounting and financial reporting policies from those reflected in the Annual Report on Form 10-K for the year ended December 31, 2017 . For further information with regard to the Company’s Significant Accounting Policies, please refer to Note 1, "Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies," to the Company’s Consolidated Financial Statements included in the 2017 Annual Report on Form 10-K.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	Revenue from Contracts with Customers Short-Term Arrangements The majority of the Company’s revenue is generated from short-term arrangements associated with the production and sale of concrete admixtures and cement additives within its SCC operating segment, as well as sheet and liquid membrane systems and other specialty products designed to protect the building envelope within its SBM operating segment. The products sold are priced based on the costs of producing goods and the value delivered to the customer. In these arrangements, the customer generally pays GCP for the contract price agreed upon within a short period of time, which is between thirty and sixty days. For such arrangements, the transfer of control takes place at a point in time when products are shipped to the customer. The evaluation of transfer of control for these goods does not involve significant judgment. Revenue from these contracts with customers is therefore typically recognized upon shipment of the product or delivery at the customer’s site depending on the shipping terms, provided the transaction price can be estimated appropriately and the Company expects to collect the consideration to which it is entitled in exchange for the products it ships. The Company generates revenue from short-term arrangements within its SCC operating segment which involve selling concrete admixtures and providing dispensers to customers. GCP has determined that the dispensers represent a lease and has allocated revenue between the lease and non-lease components based on the relative stand-alone selling price of each component which is determined based on a cost plus a reasonable margin approach for the lease component and standalone selling prices for the non-lease component. The Company recognizes revenue for the non-lease component at a point of time when the control is transferred to the customer. The lease component is considered a short-term obligation which is generally thirty days or less. The Company recognizes revenue for the lease component over the term of the lease in accordance with provisions of Topic 840. GCP records dispensers as fixed assets and depreciates them over their estimated useful life. Long-Term Arrangements The Company generates revenue from long-term arrangements within its SCC operating segment, which generally consist of VERIFI ® and Ductilcrete sales arrangements. VERIFI ® sales arrangements involve installing equipment on the customers’ trucks and at their plants, as well as performing slump management and truck location tracking services. The Company has determined that the installed equipment represents a lease. The Company allocates the transaction price in a VERIFI ® sales arrangement between the lease and non-lease components based on valuation techniques that estimate a relative stand-alone selling price of each component. The services included within the non-lease component represent the Company’s stand-ready promise to perform a series of daily distinct services, which is combined into a single performance obligation. The Company recognizes revenue associated with such services over time since the customer simultaneously receives and consumes the benefits provided by such services. The transaction price in a VERIFI ® sales arrangement consists of installation fees and slump management fees which are dependent on the quantity of materials poured and represent variable consideration. The Company records the amount of variable consideration at the time of the transfer of services to its customers, which is constrained by the amount for which a significant revenue reversal is not probable to occur. Revenue for the lease component is recognized over the term of the lease in accordance with provisions of Topic 840. Revenue generated from VERIFI ® sales arrangements represented less than 10% of the Company's consolidated revenue during the three and nine months ended September 30, 2018 . Ductilcrete sales arrangements include licenses without significant standalone functionality and usage fees received upfront, both of which represent separate performance obligations for which revenue is recognized over the period of related services. Additional performance obligations included in these arrangements are related to other fees and product sales for which revenue is recognized at a point in time once such performance obligations are satisfied. Revenue generated from Ductilcrete sales arrangements represented less than 10% of the Company's consolidated revenue during the three and nine months ended September 30, 2018 . Lease elements within sales arrangements Certain sales arrangements within the SCC operating segment related to VERIFI ® and certain admixture contracts include lease components, as discussed above. Revenue for the lease components are recognized over the term of the leases in accordance with provisions of Topic 840. During the three and nine months ended September 30, 2018 , the Company recognized revenue of $8.6 million and $25.0 million , respectively, related to the lease components of the arrangements within the SCC operating segment. Other revenue considerations The Company generally provides warranties that its products will function as intended. GCP accrues a general warranty liability at the time of sale based on historical experience and on a transaction-specific basis according to individual facts and circumstances. The Company accepts returns for certain products sales. These returns are at the discretion of the Company and typically are only granted within six months from the date of sale. GCP accrues for these returns at the time of the sale based on historical experience and records them as a reduction of transaction price. Certain long-term agreements with customers may include one-time, upfront payments made to customers. GCP defers these costs and recognizes them as assets which get amortized over the term of the agreement as a reduction of gross sales. Certain customer arrangements include conditions for volume rebates. GCP records a rebate allowance and reduces transaction price for anticipated selling price adjustments at the time of sale. GCP regularly reviews and estimates rebate accruals based on actual and anticipated sales patterns. The Company also evaluates contracts with customers that contain early payment discounts and reduces transaction price by the amount not expected to be collected due to such discounts in any given period. The Company does not include any taxes (i.e. sales, use, value added and some excise taxes) in the transaction price that is allocated among its products or services. The Company has elected to account for shipping and handling costs as fulfillment activities under the provisions of Topic 606 allowing it to continue its current treatment of the associated revenue and costs under the new standard. GCP expenses shipping and handling costs in the period they are incurred and presents them within "Cost of goods sold" in the accompanying unaudited Consolidated Statements of Operations. The Company’s revenue is principally recognized as goods and services are delivered and performance obligations are satisfied upon delivery. The Company has certain long-term arrangements resulting in remaining obligations for which the work has not been performed or has been partially performed. As of September 30, 2018 , the aggregate amount of the transaction price allocated to remaining performance obligations was $4.5 million , including the estimated transaction price to be earned as revenue over the remaining term of these contracts, which is generally one to five years.

Inventories, net

Inventories, net	9 Months Ended
	Sep. 30, 2018
Inventory Disclosure [Abstract]
Inventories, net	Inventories, net Inventories are stated at the lower of cost or net realizable value. Cost is determined on a first-in, first-out ("FIFO") basis. GCP provides reserves for excess, obsolete or damaged inventories based on their expected selling price, net of completion and disposal costs. The following is a summary of inventories presented on GCP's accompanying unaudited Consolidated Balance Sheets at September 30, 2018 and December 31, 2017: (In millions) September 30, December 31, Raw materials $ 47.3 $ 41.9 In process 4.4 3.5 Finished products and other 64.2 60.9 Total inventories, net $ 115.9 $ 106.3 The "Finished products and other" category presented in the table above includes "other" inventories, which consist of finished products purchased rather than produced by GCP of $14.2 million and $11.1 million , respectively, as of September 30, 2018 and December 31, 2017 .

Debt and Other Borrowings

Debt and Other Borrowings	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Debt and Other Borrowings	Debt and Other Borrowings Components of Debt The following is a summary of obligations under senior notes and other borrowings at September 30, 2018 and December 31, 2017: (In millions) September 30, December 31, 5.5% Senior Notes due in 2026, net of unamortized debt issuance costs of $4.5 million at September 30, 2018 $ 345.5 $ — 9.5% Senior Notes due in 2023, net of unamortized debt issuance costs of $6.4 million at December 31, 2017 — 518.6 Revolving credit facility due 2023 (1) — — Other borrowings (2) 12.1 25.7 Total debt 357.6 544.3 Less debt payable within one year 10.9 24.0 Debt payable after one year $ 346.7 $ 520.3 Weighted average interest rates on total debt obligations 5.7 % 9.4 % __________________________ (1) Represents borrowings under the Revolving Credit Facility with an aggregate available principal amount of $350.0 million and $250.0 million , respectively, as of September 30, 2018 and December 31, 2017. (2) Represents borrowings under various lines of credit and other borrowings, primarily by non-U.S. subsidiaries. The principal maturities of debt obligations outstanding, net of debt issuance costs, were as follows at September 30, 2018 : (In millions) Year ending December 31, Amount 2018 $ 10.4 2019 1.2 2020 0.5 2021 — 2022 — Thereafter 345.5 Total debt $ 357.6 Debt Refinancing On April 10, 2018, GCP redeemed its then existing 9.5% Senior Notes with an aggregate principal amount of $525.0 million due in 2023 (the “ 9.5% Senior Notes”). On April 10, 2018, the Company also issued 5.5% Senior Notes with an aggregate principal amount of $350.0 million maturing on April 15, 2026 (the " 5.5% Senior Notes") and amended its Credit Agreement to, among other things, (i) increase the aggregate principal amount available under its revolving credit facility to $350.0 million , (ii) extend the maturity date of the revolving credit facility thereunder to April 2023 and (iii) make certain other changes to the covenants and other provisions therein. Additionally, the Company borrowed $50.0 million in aggregate principal amount of revolving loans under the Credit Agreement on April 10, 2018 which was fully repaid during the second quarter of 2018. The aggregate cash payment of $587.9 million , which consisted of: (i) proceeds of $350.0 million from the issuance of the 5.5% Senior Notes, net of loan origination fees of $3.1 million , (ii) borrowings of $50.0 million under the Credit Agreement, and (iii) a cash payment of $191.0 million was used to redeem all of the then outstanding 9.5% Senior Notes in accordance with the terms of the indenture governing the 9.5% Senior Notes. The redemption of the 9.5% Senior Notes was accounted for as a debt extinguishment in accordance with provisions of ASC Topic 470-50, Debt Modifications and Extinguishments . During the nine months ended September 30, 2018, GCP recognized a loss on debt extinguishment of $59.4 million which was included in "Interest expense and related financing costs" in the accompanying unaudited Consolidated Statements of Operations. In connection with the redemption of the 9.5% Senior Notes with then outstanding principal balance of $525.0 million , GCP paid total cash proceeds of $587.9 million , including $53.3 million of a redemption premium and $9.6 million of accrued interest unpaid thereon through the redemption date, and wrote off $6.1 million of previously deferred debt issuance costs. The amendment to the Credit Agreement among GCP and a syndicate of financial institutions resulted in an increase in a maximum borrowing capacity under the Revolving Credit Facility from $250.0 million to $350.0 million and extension of the maturity date to April 2023. During the nine months ended September 30, 2018, GCP wrote off $0.4 million of deferred debt issuance costs related to a financial institution that exited the syndicate upon amendment of the Credit Agreement. As of September 30, 2018 , debt issuance costs of $4.3 million related to the financial institutions that remained in the syndicate are presented within "Other assets" in the accompanying unaudited Consolidated Balance Sheets and amortized over the term of the Revolving Credit Facility. The total loss recognized on the debt refinancing transaction was $59.8 million which was included in "Interest expense and related financing costs" in the accompanying unaudited Consolidated Statements of Operations and consisted of $59.4 million related to the extinguishment of the 9.5% Senior Notes and $0.4 million related to a deferred issuance costs write-off in connection with the amendment of the Credit Agreement. 5.5% Senior Notes On April 10, 2018, GCP issued 5.5% Senior Notes with an aggregate principal amount of $350.0 million maturing on April 15, 2026. The 5.5% Senior Notes were issued at $346.9 million , or 99.1% of their par value, resulting in a discount of $3.1 million , or 0.9% , which represented loan origination fees paid at the closing. The Company incurred additional deferred financing costs of $1.6 million related to the issuance. Interest is payable semi-annually in arrears on April 15 and October 15 of each year, commencing on October 15, 2018. An interest payment of $9.9 million was due and paid on October 15, 2018. The 5.5% Senior Notes were issued pursuant to an Indenture (the “Indenture”), by and among GCP, the guarantors party thereto (the “Note Guarantors”) and Wilmington Trust, National Association, as trustee. The 5.5% Senior Notes and the related guarantees rank equally with all of the existing and future unsubordinated indebtedness of GCP and the Note Guarantors and senior in right of payment to any existing and future subordinated indebtedness of GCP and the Note Guarantors. The 5.5% Senior Notes and related guarantees are effectively subordinated to any secured indebtedness of GCP or the Note Guarantors, as applicable, to the extent of the value of the assets securing such indebtedness and structurally subordinated to all existing and future indebtedness and other liabilities of GCP’s non-guarantor subsidiaries. Subject to certain conditions stated in the Indenture, GCP may, at its option and at any time and from time to time prior to April 15, 2021, redeem the 5.5% Senior Notes in whole or in part at a redemption price equal to: (i) 100% of their principal amount redeemed, plus (ii) the applicable premium, as defined in the Indenture, plus (iii) accrued and unpaid interest, if any, to, but excluding, the applicable redemption date. In addition, GCP may, at its option, redeem up to 40% of the outstanding principal amount of the 5.5% Senior Notes at any time and from time to time prior to April 15, 2021 with the net cash proceeds from certain equity offerings at a redemption price equal to: (i) 105.5% of the principal amount redeemed, plus (ii) accrued and unpaid interest, if any, to, but excluding, the applicable redemption date. At any time and from time to time on or after April 15, 2021, GCP may, at its option, redeem the 5.5% Senior Notes in whole or in part at the redemption price equal: (i) 102.8% of the par value if redeemed after April 15, 2021, (ii) 101.4% of the par value if redeemed after April 15, 2022, and (iii) 100.0% of the par value if redeemed after April 15, 2023 and thereafter. Upon occurrence of a change of control, as defined in the Indenture, GCP will be required to make an offer to repurchase the 5.5% Senior Notes at a price equal to 101.0% of their aggregate principal amount repurchased plus accrued and unpaid interest, if any, to, but excluding, the date of repurchase. The Indenture contains covenants that limit the ability of GCP and its subsidiaries, subject to certain exceptions and qualifications set forth therein, to (i) create or incur liens on certain assets, (ii) incur additional debt, (iii) make certain investments and acquisitions, (iv) consolidate, merge, or convey, transfer, or lease all or substantially all of their assets, (v) sell certain assets, (vi) pay dividends on or make distributions in respect of GCP’s capital stock or make other restricted payments, (vii) enter into certain transactions with GCP’s affiliates and (viii) place restrictions on distributions from and other actions by subsidiaries. As of September 30, 2018 , the Company was in compliance with all covenants and conditions under the Indenture. The Indenture provides for customary events of default which are subject in certain cases to customary grace periods and include, among others: (i) nonpayment of principal or interest, (ii) breach of other agreements in the Indenture, (iii) failure to pay certain other indebtedness, (iv) certain events of bankruptcy or insolvency, (v) failure to discharge final judgments aggregating in excess of $50.0 million rendered against GCP or certain of its subsidiaries, (vi) and failure of the guarantee of the 5.5% Senior Notes by any of GCP’s significant subsidiaries to be in full force and effect. There are no events of default under the Indenture as of September 30, 2018 . Credit Agreement On February 3, 2016, GCP entered into a Credit Agreement that provides for senior secured credit facilities (the “Credit Facilities”) in an aggregate principal amount of $525.0 million , which consisted of: (i) the term loan (the "Term Loan") with an aggregate principal amount of $275.0 million and (ii) a revolving credit facility (the "Revolving Credit Facility") of $250.0 million due in 2021. During 2017, the Company fully repaid the outstanding principal balance on the Term Loan together with accrued and unpaid interest and extinguished the Term Loan under the Credit Agreement. On April 10, 2018, GCP entered into an amendment to its Credit Agreement and borrowed $50.0 million in aggregate principal amount of revolving loans under the Credit Agreement, as discussed above, which was fully repaid during the second quarter of 2018. The Credit Agreement contains conditions that would require mandatory principal payments in advance of the maturity date of the Revolving Credit Facility, as well as certain customary affirmative and negative covenants and events of default, as described in Note 5, "Debt and Other Financial Instruments," to the Company's Consolidated Financial Statements included in the 2017 Annual Report in the Form 10-K. The Company was in compliance with all covenant terms as of September 30, 2018 and December 31, 2017. There are no events of default as of September 30, 2018 and December 31, 2017. The Revolving Credit Facility is secured on a first priority basis by a perfected security interest in, and mortgages on substantially all U.S. tangible and intangible personal property, financial assets and real property owned by the Company in Chicago, Illinois and Mount Pleasant, Tennessee; a pledge of 100% of the equity of each material U.S. subsidiary of the Company; and 65% of the equity of a U.K. holding company. The interest rate per annum applicable to the Revolving Credit Facility is equal to, at GCP’s option, either: (i) a base rate plus a margin ranging from 0.5% to 1.0% , or (ii) LIBOR plus a margin ranging from 1.5% to 2.0% , based upon the total leverage ratio of GCP and its restricted subsidiaries in both scenarios. During the three and nine months ended September 30, 2018 , the weighted average interest rate paid on the Revolving Credit Facility was 0.0% and 3.4% , respectively. During the nine months ended September 30, 2018 , GCP made aggregate payments of $50.0 million on the Revolving Credit Facility. As of September 30, 2018 , there were no outstanding borrowings on the Revolving Credit Facility and approximately $5.7 million in outstanding letters of credit, which resulted in available credit of $344.3 million under the Revolving Credit Facility. As of December 31, 2017, there were no outstanding borrowings under the Revolving Credit Facility. There were no interest payments on the Revolving Credit Facility during the three months ended September 30, 2018 . Such interest payments were $0.2 million during the nine months ended September 30, 2018 . 9.5% Senior Notes On January 27, 2016, GCP issued $525.0 million aggregate principal amount of 9.5% Senior Notes maturing in 2023. Interest was payable semi-annually in arrears on February 1 and August 1 of each year. The 9.5% Senior Notes became callable at a premium over their face amount on February 1, 2019 and were redeemable prior to February 1, 2019 at a price that reflected a yield to the first call that was equivalent to the applicable Treasury bond yield plus 0.5 percentage points. On April 10, 2018, GCP redeemed all of the then outstanding 9.5% Senior Notes, as described above, and paid $9.6 million of accrued interest unpaid thereon through their redemption date. The 9.5% Senior Notes were subject to covenants that limited GCP's and certain of its subsidiaries’ ability, subject to certain exceptions and qualifications, to (i) create or incur liens on assets; (ii) incur additional debt; (iii) sell certain assets; and (iv) make certain investments and acquisitions, merge or sell or otherwise dispose of all or substantially all assets. Debt Issuance Costs GCP recognizes expenses directly associated with obtaining the Revolving Credit Facility as debt issuance costs which are presented within "Other assets" in the accompanying unaudited Consolidated Balance Sheets. Such costs are amortized over the term of the Revolving Credit Facility and included in “Interest expense and related financing costs” in the accompanying unaudited Consolidated Statements of Operations. Debt issuance costs related to the Revolving Credit Facility were $4.3 million as of September 30, 2018 and $3.2 million as of December 31, 2017 . During the nine months ended September 30, 2018, GCP wrote off $0.4 million of debt issuance costs related to a financial institution that exited the syndicate upon amendment of the Credit Agreement which governs the Revolving Credit Facility. During the nine months ended September 30, 2018, GCP incurred debt issuance costs of $2.2 million due to the amendment of the Credit Agreement. Debt issuance costs of $4.7 million , including loan origination fees of $3.1 million paid at the closing, are directly associated with issuing the 5.5% Senior Notes and presented as a reduction of the principal balance in the accompanying unaudited Consolidated Balance Sheets. Such costs are amortized over the term of the 5.5% Senior Notes using the effective interest rate method and included in “Interest expense and related financing costs” in the accompanying unaudited Consolidated Statements of Operations. At September 30, 2018 , the remaining unamortized debt issuance costs related to the 5.5% Senior Notes were $ 4.5 million . During the nine months ended September 30, 2018 , GCP wrote off $6.1 million of previously deferred debt issuance costs related to the 9.5% Senior Notes in connection with their redemption. Debt Fair Value At September 30, 2018 , the carrying amounts and fair values of GCP's debt were as follows: September 30, 2018 December 31, 2017 (In millions) Carrying Amount Fair Value Carrying Amount Fair Value 9.5% Senior Notes due in 2023 $ — $ — $ 518.6 $ 584.5 5.5% Senior Notes due in 2026 345.5 344.0 — — Other borrowings 12.1 12.1 25.7 25.7 Total debt $ 357.6 $ 356.1 $ 544.3 $ 610.2 Fair value is determined based on Level 2 inputs, including expected future cash flows discounted at market interest rates, estimated current market prices and quotes from financial institutions. The decrease in fair value as of September 30, 2018 was primarily due to the market trend of increasing interest rates.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income tax expense (benefit) attributable to continuing operations during the three months ended September 30, 2018 and 2017 was $7.6 million and ( $14.5 million ), respectively, representing effective tax rates of 51.0% and 44.6% , respectively. The difference between the provision for income taxes at the U.S. federal income tax rate of 21.0% and GCP’s overall income tax rate for the three months ended September 30, 2018 was primarily attributable to valuation allowances recorded of $3.6 million , the effect of tax rates in foreign jurisdictions of $0.2 million , and permanent book-to-tax differences and other items of $0.7 million . The difference between the provision for income taxes at the U.S. federal income tax rate of 35.0% and GCP's overall income tax rate for the three months ended September 30, 2017 was primarily due to $2.9 million of tax benefit on undistributed foreign earnings. Income tax expense attributable to continuing operations during the nine months ended September 30, 2018 and 2017 was $15.8 million and $3.7 million , respectively, representing effective tax rates of 80.2% and 9.8% , respectively. The difference between the provision for income taxes at the U.S. federal income tax rate of 21.0% and GCP’s overall income tax rate for the nine months ended September 30, 2018 was primarily attributable to changes in estimates related to the 2017 Tax Act in the amount of $12.5 million , income tax valuation allowances of $4.7 million , tax rates in foreign jurisdictions of $0.9 million , and permanent book-to-tax differences and other items of $1.8 million . The difference in income tax at the U.S. federal income rate of 35.0% and GCP's overall income tax rate for the nine months ended September 30, 2017 was primarily due to an income tax valuation allowance of $13.9 million , tax expense on undistributed foreign earnings of $3.6 million , and tax benefit on permanent book-to-tax differences and other items of $0.5 million . During the three and nine months ended September 30, 2018 , GCP recorded income tax expense attributable to discontinued operations of $6.1 million and $14.0 million , respectively, compared to $200.0 million and $199.7 million , respectively, for the three and nine months ended September 30, 2017 . Please refer to Note 15, "Discontinued Operations," to the accompanying unaudited Consolidated Financial Statements for further details regarding the Darex transaction. Tax Reform During the year ended December 31, 2017, the Company recorded a provisional net charge of $81.7 million related to the provisions of the 2017 Tax Act, which was comprised of a $70.5 million Transition Toll Tax and a $11.2 million revaluation of net deferred tax assets. Changes in tax rates and tax laws are accounted for in the period of enactment. In the first quarter of 2018, the Company recorded an increase to the provisional net charge related to the 2017 Tax Act provisions of $12.5 million . This change consisted of an increase of $17.4 million related to capital gain treatment triggered in 2017 due to the 2017 Tax Act, an increase of $0.3 million deferred tax expense related to executive compensation, and a decrease of $5.2 million related to the 2017 Transition Toll Tax. There were no adjustments to the provisional net charge recorded during the second or third quarters of 2018. The Company's preliminary estimate of the Transition Toll Tax and the remeasurement of its deferred tax assets and liabilities is subject to the finalization of management’s analysis related to certain matters, such as developing interpretations of the provisions of the 2017 Tax Act, changes to certain estimates and amounts related to the earnings and profits of certain subsidiaries and the filing of the Company's tax returns. U.S. Treasury regulations, administrative interpretations or court decisions interpreting the 2017 Tax Act may require further adjustments and changes in our estimates. The 2017 final determination of the Transition Toll Tax and remeasurement of our deferred assets and liabilities will be completed as additional information becomes available, but no later than one year from the enactment of the 2017 Tax Act. The 2017 Tax Act subjects a U.S. shareholder to tax on Global Intangible Low Taxed Income (GILTI) earned by foreign subsidiaries. The Company has not determined its accounting policy with respect to GILTI and has therefore included the estimate of current year GILTI as a period cost and included it as part of the estimated 2018 annual effective tax rate. The 2018 estimated annual effective tax rate also includes the 2018 impact of all other U.S. tax reform provisions that were effective on January 1, 2018. For additional information related to the 2017 Tax Act, please refer to Note 6, "Income Taxes," to the Company's Consolidated Financial Statements included in the 2017 Annual Report on Form 10-K. Repatriation As of December 31, 2017, no provision has been made for income taxes on certain undistributed earnings of foreign subsidiaries the Company provisionally intends to permanently reinvest or that may be remitted substantially tax-free. Due to the transition tax on deemed repatriation required by the 2017 Tax Act, the Company has been subject to tax on substantially all of its previously undistributed earnings from foreign subsidiaries, which it provisionally recorded in the fourth quarter of 2017. Beginning in 2018, the Act will generally provide a 100% deduction for U.S. federal tax purposes of all dividends received by the Company from its foreign subsidiaries. However, the Company is currently evaluating the potential foreign and U.S. state tax liabilities that would result from future repatriations, if any, and how the 2017 Tax Act will affect the Company's existing accounting position with regard to its indefinite reinvestment of undistributed foreign earnings assertion. The Company expects to complete this evaluation and determine the impact the legislation may have on its indefinite reinvestment assertion within the measurement period provided by SAB 118. During the nine months ended September 30, 2017 , GCP determined it could no longer assert it was indefinitely reinvested in Mexico and Venezuela because these entities were anticipated to be sold as part of the Darex transaction. The tax associated with its outside book and tax basis differences in Mexico and Venezuela were recorded as discrete items resulting in a tax benefit of $2.9 million for the three months ended September 30, 2017 and a tax expense of $3.6 million for the nine months ended September 30, 2017. GCP will continually analyze and evaluate its cash needs to determine the appropriateness of its indefinite reinvestment assertion, including further assessment under the 2017 Tax Act. The Company considers its assertion of indefinite reinvestment provisional as of September 30, 2018 . Valuation Allowance In evaluating GCP's ability to realize its deferred tax assets, GCP considers all reasonably available positive and negative evidence, including recent earnings experience, expectations of future taxable income and the tax character of that income, the period of time over which temporary differences become deductible and the carryforward and/or carryback periods available to GCP for tax reporting purposes in the related jurisdiction. In estimating future taxable income, GCP relies upon assumptions and estimates about future activities, including the amount of future federal, state and foreign pretax operating income that GCP will generate; the reversal of temporary differences; and the implementation of feasible and prudent tax planning strategies. GCP records a valuation allowance to reduce deferred tax assets to the amount that it believes is more likely than not to be realized. During the three and nine months ended September 30, 2018 , GCP incurred income tax expense of $3.6 million and $4.7 million for valuation allowances recorded on losses generated in certain countries; primarily Brazil, Turkey, France, Germany, India and Singapore. During the nine months ended September 30, 2017 , GCP determined it was more likely than not a portion of its deferred tax assets would not be realized. As a result, during that period, GCP recorded $13.8 million of valuation allowances on those deferred tax assets during the period as discrete items, as they are significant, unusual and infrequent in nature. The valuation allowances were recorded against U.S. foreign tax credit carryovers of $4.3 million , and deferred tax assets primarily related to net operating loss carryovers in Brazil and Turkey of $9.1 million and $0.4 million , respectively. The determination to record the valuation allowances was made predominantly due to the anticipated sale of Darex and its impact on future taxable income and the ability to utilize those tax assets. In connection with the Separation, GCP and Grace entered into various agreements that govern the relationship between the parties going forward, including a tax matters agreement (the "Tax Sharing Agreement"). Under the Tax Sharing Agreement, which was entered into on the distribution date, GCP and Grace will indemnify and hold each other harmless in accordance with the principles outlined therein. During the nine months ended September 30, 2017 , GCP reached a proposed favorable settlement with the Canada Revenue Agency for tax years 2007 through 2015. As a result, a tax benefit of $1.5 million , primarily for an anticipated refund of previously paid tax, was recorded during the period. GCP is required to pay Grace for the amount of the expected tax refund pursuant to the Tax Sharing Agreement. GCP also recorded a charge to its U.S. deferred tax assets of $1.6 million in the period related to the settlement due to the reduction of its step-up in tax basis. Both adjustments were recorded as discrete tax items. During the nine months ended September 30, 2018, GCP filed amended tax returns with the Canada Revenue Agency reflecting the anticipated refunds. As discussed in Note 4, "Debt and Other Borrowings", GCP recognized a loss during the nine months ended September 30, 2018 of $59.8 million associated with its debt refinancing. Because this loss is unusual and infrequent in nature, the tax effect of the loss was recorded as a discrete tax item in the second quarter. The tax benefit recorded associated with the loss is $14.8 million .

Pension Plans and Other Postret

Pension Plans and Other Postretirement Benefit Plans	9 Months Ended
	Sep. 30, 2018
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Pension Plans and Other Postretirement Benefit Plans	Pension Plans and Other Postretirement Benefit Plans Pension Plans GCP sponsors certain defined benefit pension plans, primarily in the U.S. and the U.K., in which GCP employees participate. GCP records an asset or a liability to recognize the funded status of these pension plans in its accompanying unaudited Consolidated Balance Sheets. The following table presents the funded status of GCP's overfunded, underfunded and unfunded defined pension plans related to continuing operations: (In millions) September 30, December 31, Overfunded defined benefit pension plans $ 26.1 $ 26.4 Underfunded defined benefit pension plans (26.4 ) (26.6 ) Unfunded defined benefit pension plans (30.2 ) (30.5 ) Total underfunded and unfunded defined benefit pension plans (56.6 ) (57.1 ) Pension liabilities included in other current liabilities (2.0 ) (1.0 ) Net funded status $ (32.5 ) $ (31.7 ) Overfunded plans include several advance-funded plans for which the fair value of the plan assets exceeds the projected benefit obligation (the "PBO"). The overfunded status is reflected as assets in "Overfunded defined benefit pension plans" in the accompanying unaudited Consolidated Balance Sheets. Underfunded plans include a group of advance-funded plans that are underfunded on a PBO basis. Unfunded plans include several plans that are funded on a pay-as-you-go basis, and therefore, the entire PBO is unfunded. As of September 30, 2018 and December 31, 2017, the underfunded and unfunded plans are included as liabilities in the accompanying unaudited Consolidated Balance Sheets. There were no curtailment or mark-to-market gains or losses recorded during the three months ended September 30, 2018. During the three months ended September 30, 2017, certain pension plans were curtailed and/or terminated resulting in consolidated curtailment gains of $17.1 million and consolidated mark-to-market losses of $2.9 million , of which $16.4 million and $0.1 million are presented in "Income from discontinued operations, net of income taxes" in the accompanying unaudited Consolidated Statements of Operations. Such curtailment gains and mark-to-market losses were primarily attributable to the divestiture of the Darex operating segment and restructuring activities. During the nine months ended September 30, 2018, curtailment and mark-to-market remeasurement amounts include $0.4 million of gains recorded during the second quarter of 2018 related to a non-U.S pension plan. During the nine months ended September 30, 2017, consolidated curtailment gains amounted to $22.7 million and consolidated mark-to-market losses amounted to $2.8 million which were primarily attributable to the divestiture of the Darex operating segment, amendment to the GCP Applied Technologies, Inc. Retirement Plan for Salaried Employees that closed the plan to new hires effective January 1, 2018, as well as restructuring activities. Of those amounts, $16.9 million and $0.1 million , respectively, are presented in "Income from discontinued operations, net of income taxes" in the accompanying unaudited Consolidated Statements of Operations, in addition to expense of $0.5 million for service cost, interest cost, and expected return on plan assets. Please refer to Note 7, "Pension Plans and Other Postretirement Benefit Plans" to the Company's Consolidated Financial Statements included in the 2017 Annual Report in the Form 10-K for further information on these transactions. Components of Net Periodic Benefit Cost The components of GCP's net periodic benefit cost for the three and nine months ended September 30, 2018 and 2017 are as follows: Three Months Ended September 30, 2018 2017 Pension Pension (In millions) U.S. Non-U.S. U.S. Non-U.S. Service cost $ 2.0 $ 0.8 $ 1.6 $ 0.8 Interest cost 1.4 1.4 1.3 1.4 Expected return on plan assets (1.9 ) (1.7 ) (1.4 ) (1.6 ) Mark-to-market adjustment — — 1.2 1.7 Gain on curtailments, settlements, and terminations — — (2.8 ) (14.3 ) Net periodic benefit cost (income) $ 1.5 $ 0.5 $ (0.1 ) $ (12.0 ) Less: Discontinued operations net periodic benefit income — — (2.1 ) (14.4 ) Net periodic benefit cost from continuing operations $ 1.5 $ 0.5 $ 2.0 $ 2.4 Nine Months Ended September 30, 2018 2017 Pension Pension (In millions) U.S. Non-U.S. U.S. Non-U.S. Service cost $ 6.0 $ 2.4 $ 5.3 $ 3.0 Interest cost 4.2 4.2 4.2 4.3 Expected return on plan assets (5.7 ) (5.3 ) (4.2 ) (5.1 ) Mark-to-market adjustment — (0.3 ) 1.2 1.6 Gain on curtailments, settlements, and terminations — (0.1 ) (8.4 ) (14.3 ) Net periodic benefit cost (income) $ 4.5 $ 0.9 $ (1.9 ) $ (10.5 ) Less: Discontinued operations net periodic benefit income — — (2.6 ) (13.9 ) Net periodic benefit cost from continuing operations $ 4.5 $ 0.9 $ 0.7 $ 3.4 Other Postretirement Benefit (OPEB) Plans GCP provides postretirement health care benefits for certain qualifying retired employees. During the second quarter of 2018, GCP recognized a long-term liability of $2.0 million ; accumulated other comprehensive income of $0.6 million , net of related tax impact of $0.2 million ; as well as expense of $1.2 million , which are included within the accompanying unaudited Consolidated Balance Sheets and the accompanying unaudited Consolidated Statements of Operations. As of September 30, 2018, the related long-term liability of $1.8 million , accumulated other comprehensive income of $0.4 million , net of related tax impact of $0.1 million , are included within the accompanying unaudited Consolidated Balance Sheets. The related expense for the three and nine months ended September 30, 2018 was $0.1 million and $1.3 million , respectively. Plan Contributions and Funding GCP intends to satisfy its funding obligations under the U.S. qualified pension plans and to comply with all of the requirements of the Employee Retirement Income Security Act of 1974, as amended ("ERISA"). For ERISA purposes, funded status is calculated on a different basis than under GAAP. GCP intends to fund non-U.S. pension plans based on applicable legal requirements, as well as actuarial and trustee recommendations. During the three and nine months ended September 30, 2018 , GCP contributed $0.4 million and $4.3 million , respectively, to these non-U.S. plans, including a discretionary contribution of $2.9 million to a pension plan in Brazil. During the three and nine months ended September 30, 2017, such contributions amounted to $0.2 million and $1.9 million , respectively. Defined Contribution Retirement Plan GCP sponsors a defined contribution retirement plan for its employees in the U.S. which is a qualified plan under section 401(k) of the U.S. tax code. Under this plan, GCP contributes an amount equal to 100% of employee contributions, up to 6% of an individual employee's salary or wages. Effective January 1, 2018, GCP established an additional defined contribution plan whereby GCP contributes up to an additional 2% of 100% of applicable employee contributions. Applicable employees include those beginning employment with GCP on or after January 1, 2018 who are not eligible to participate the GCP Applied Technologies Inc. Retirement Plan for Salaried Employees, which closed to new hires effective January 1, 2018. GCP's costs related to these benefit plans are included in "Selling, general and administrative expenses" and "Cost of goods sold" in the accompanying unaudited Consolidated Statements of Operations and amounted to $1.0 million and $3.5 million , respectively, during the three and nine months ended September 30, 2018 and $1.1 million and $3.6 million , respectively, during the three and nine months ended September 30, 2017 .

Other Balance Sheet Accounts

Other Balance Sheet Accounts	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Other Balance Sheet Accounts	Other Balance Sheet Accounts The following is a summary of other current assets at September 30, 2018 and December 31, 2017: (In millions) September 30, December 31, Other Current Assets: Non-trade receivables $ 26.4 $ 28.4 Prepaid expenses and other current assets 9.6 13.8 Income taxes receivable 11.2 6.0 Marketable securities — 0.4 Total other current assets $ 47.2 $ 48.6 The following is a summary of other current liabilities at September 30, 2018 and December 31, 2017: (In millions) September 30, December 31, Other Current Liabilities: Accrued customer volume rebates $ 33.2 $ 31.5 Accrued compensation (1) 16.7 27.1 Income taxes payable (2) 25.7 115.1 Accrued interest 9.4 20.8 Pension liabilities 2.0 1.0 Restructuring liability 13.3 12.8 Other accrued liabilities (3) 56.5 107.9 Total other current liabilities $ 156.8 $ 316.2 ________________________________ (1) Accrued compensation presented in the table above includes salaries and wages, as well as estimated current amounts due under the annual and long-term employee incentive programs. (2) The change in income taxes payable between September 30, 2018 and December 31, 2017 is related primarily to the payment of $105.0 million related to the Company's provisional 2017 domestic income tax liability which was impacted by the sale of Darex and the 2017 Tax Act. (3) Other accrued liabilities presented in the table above as of September 30, 2018 and December 31, 2017 include $13.1 million and $55.1 million , respectively, representing the current portion of the liability related to the delayed closings associated with the Company's divestiture of Darex, as discussed in Note 15, "Discontinued Operations."

Commitments and Contingent Liab

Commitments and Contingent Liabilities	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	Commitments and Contingent Liabilities GCP enters into certain purchase commitments and is a party to many contracts containing guarantees and indemnification obligations, as described in Note 9, "Commitments and Contingent Liabilities" to the Company's Consolidated Financial Statements included in the 2017 Annual Report in the Form 10-K. There have been no material changes to these commitments and obligations during the three and nine months ended September 30, 2018 . Environmental Matters GCP is subject to loss contingencies resulting from extensive and evolving federal, state, local and foreign environmental laws and regulations relating to the generation, storage, handling, discharge, disposition and stewardship of hazardous wastes and other materials. GCP recognizes accrued liabilities for anticipated costs associated with response efforts if, based on the results of the assessment, it concluded that a probable liability has been incurred and the cost can be reasonably estimated. As of September 30, 2018 and December 31, 2017, GCP did no t have any material environmental liabilities. GCP's environmental liabilities are reassessed whenever circumstances become better defined or response efforts and their costs can be better estimated. These liabilities are evaluated based on currently available information, including the progress of remedial investigations at each site, the current status of discussions with regulatory authorities regarding the method and extent of remediation at each site, existing technology, prior experience in contaminated site remediation and the apportionment of costs among potentially responsible parties. Financial Assurances Financial assurances have been established for a variety of purposes, including insurance, environmental matters and other matters. At September 30, 2018 and December 31, 2017, GCP had gross financial assurances issued and outstanding of approximately $6 million and $10 million , respectively, which were composed of standby letters of credit. Lawsuits and Investigations From time to time, GCP and its subsidiaries are parties to, or targets of, lawsuits, claims, investigations and proceedings which are managed and defended in the ordinary course of business. While GCP is unable to predict the outcome of these matters, it does not believe, based upon currently available facts, that the ultimate resolution of any of such pending matters will have a material adverse effect on its overall financial condition, results of operations or cash flows for the three and nine months ended September 30, 2018 . Accounting for Contingencies Although the outcome of each of the matters discussed above cannot be predicted with certainty, GCP has assessed the risk and has made accounting estimates and disclosures as required under GAAP.

Restructuring and Repositioning

Restructuring and Repositioning Expenses	9 Months Ended
	Sep. 30, 2018
Restructuring and Related Activities [Abstract]
Restructuring and Repositioning Expenses	Restructuring and Repositioning Expenses GCP's Board of Directors approves all major restructuring programs that may involve the discontinuation of significant product lines or the shutdown of significant facilities. From time to time, GCP takes additional restructuring actions, including involuntary employee terminations that are not a part of a major program. Restructuring programs generally include severance and other employee-related costs, contract or lease termination costs, asset impairments, facility exit costs, moving and relocation, and other related costs. The Company may also undertake repositioning activities that generally represent major strategic or transformational actions to enhance the value and performance of the Company, improve business efficiency or optimize the Company’s footprint. Repositioning expenses include professional fees for legal, consulting, accounting and tax services, employment-related costs, such as recruitment, relocation and compensation, as well as other expenses incurred that are directly associated with the repositioning activity. Repositioning activities may also include capital expenditures. GCP recognizes restructuring and repositioning costs in the period the related liabilities are incurred and records them in "Restructuring and asset impairments" and “Repositioning expenses,” or in those captions within discontinued operations, in the accompanying unaudited Consolidated Statements of Operations. Restructuring expenses, asset impairments and repositioning expenses are excluded from segment operating income. 2018 Restructuring and Repositioning Plan (the “2018 Plan”) On August 1, 2018, the Board of Directors of the Company approved a business restructuring and repositioning plan. The 2018 Plan is designed to streamline operations and improve profitability primarily within the concrete admixtures product line of the Specialty Construction Chemicals segment by focusing on the Company's core markets, rationalizing non-profitable geographies, reducing its global cost structure and accelerating the integration of VERIFI® into the Company’s global admixtures business. The Company expects to incur total costs in connection with the 2018 Plan ranging from approximately $30 million to $35 million , of which costs ranging from approximately $20 million to $25 million are related to restructuring activities, and costs of approximately $10 million are related to repositioning activities. Total expected restructuring activity costs consist of approximately $13 million to $16 million of severance and other employee-related costs, $4 million of asset impairments, $1 million to $2 million of facility exit costs and $3 million of other associated costs. Total expected restructuring activity costs are attributable as follows: (i) $18.0 million to $ 21.0 million to the SCC segment and (ii) $3.0 million to $4.0 million to the SBM segment. Substantially all of the restructuring actions are expected to be completed by December 31, 2019 and result in the net reduction of approximately 8% - 10% of the Company's workforce. Repositioning costs consist primarily of consulting services to assist GCP in advancing its technology strategy. Total costs expected to be incurred for repositioning activities are approximately $10 million . Substantially all of the repositioning activities are expected to be completed by December 31, 2019. As of September 30, 2018 , the cumulative restructuring activity costs recognized under the 2018 Plan since inception were $14.3 million , of which $12.0 million was attributable to the SCC segment and $2.3 million was attributable to the SBM segment. Of the $14.3 million incurred to date, $10.3 million was related to severance and employee-related costs and $4.0 million was related to asset impairments. As of September 30, 2018, the cumulative repositioning activity costs recognized under the 2018 Plan since inception were approximately $2.6 million . The Company expects to settle in cash approximately 70% of the restructuring costs and substantially all of the repositioning costs related to the 2018 Plan. 2017 Restructuring and Repositioning Plan (the “2017 Plan”) On June 28, 2017, the Board of Directors approved a restructuring and repositioning plan that includes actions to streamline GCP's operations, reduce its global cost structure and reposition itself as a construction products technologies company. GCP expects to incur total costs in connection with the 2017 Plan of approximately $30 million , of which $20 million is related to restructuring activities, and $10 million is related to repositioning activities. Total expected restructuring activity costs consist of approximately $18 million of severance and other employee-related costs, and $2 million of asset impairments and facility exit costs. Total expected restructuring activity costs are attributable as follows: (i) $5 million to the SCC segment, (ii) $3 million to the SBM segment, (iii) $3 million to the Corporate function and (iv) $9 million to discontinued operations. The restructuring activities are expected to be substantially completed by December 31, 2018. Total costs expected to be incurred for repositioning activities are $10 million . Additionally, GCP expects to incur approximately $10 million to $15 million of capital expenditures related to repositioning activities, which includes the build-out of three manufacturing plants in Asia Pacific that will replace shared facilities sold as a part of the Darex divestiture. GCP expects all of its repositioning activities to be classified within continuing operations and such repositioning activities should be substantially completed by December 31, 2019. As of September 30, 2018 , the cumulative restructuring activity costs recognized under the 2017 Plan since inception were $19.4 million , of which $4.6 million was attributable to the SCC segment, $3.3 million was attributable to the SBM segment, $2.9 million was attributable to the Corporate function and $8.6 million was attributable to discontinued operations. Of the $19.4 million incurred to date, $17.6 million related to severance and employee-related costs and $1.8 million related to asset impairments and facility exit costs. As of September 30, 2018 , the cumulative repositioning activity costs and capital expenditures recognized under the 2017 Plan since inception were approximately $7.6 million and $6.7 million , respectively. As of September 30, 2018 , cumulative cash payments for repositioning made under the 2017 Plan from inception to date, including capital expenditures were $12.0 million . The Company expects to settle in cash substantially all of the costs related to the 2017 Plan. Restructuring Expenses and Asset Impairments The following table summarizes restructuring costs and asset impairment charges related to the 2017 and 2018 Plans and other plans incurred during each period: Three Months Ended September 30, Nine Months Ended September 30, (In millions) 2018 2017 2018 2017 Severance and other employee costs $ 10.0 $ 2.1 9.3 $ 19.0 Facility exit costs 0.2 — 0.2 0.1 Asset impairments 4.1 0.4 4.5 0.8 Total restructuring expenses and asset impairments $ 14.3 $ 2.5 $ 14.0 $ 19.9 Less: restructuring expenses and asset impairments reflected in discontinued operations — 0.4 0.8 6.9 Total restructuring expenses and asset impairments from continuing operations $ 14.3 $ 2.1 $ 13.2 $ 13.0 GCP incurred restructuring costs and asset impairment charges related to its two operating segments and Corporate as follows: Three Months Ended September 30, Nine Months Ended September 30, (In millions) 2018 2017 2018 2017 SCC $ 11.9 $ 0.7 $ 10.9 $ 6.2 SBM 2.3 (0.3 ) 1.9 4.1 Corporate 0.1 1.7 0.4 2.7 Total restructuring expenses and asset impairments from continuing operations $ 14.3 $ 2.1 $ 13.2 $ 13.0 Restructuring expenses and asset impairments reflected in discontinued operations — 0.4 0.8 6.9 Total restructuring expenses and asset impairments $ 14.3 $ 2.5 $ 14.0 $ 19.9 Restructuring liabilities were $13.3 million and $12.8 million , respectively, as of September 30, 2018 and December 31, 2017 . These liabilities are included within “Other current liabilities” in the accompanying unaudited Consolidated Balance Sheets. GCP expects to settle in cash substantially all of the remaining liabilities related to the 2017 Plan by March 31, 2019, and all of the remaining liabilities related to the 2018 Plan by December 31, 2019. The following table summarizes the Company’s restructuring liability activity: 2018 Plan 2017 Plan (In millions) Severance and other employee costs Facility exit costs Severance and other employee costs Facility exit costs Other plans Total Balance, December 31, 2017 $ — $ — $ 11.6 $ 0.1 $ 1.1 $ 12.8 Expense (1) 10.3 — (1.7 ) 0.2 0.7 9.5 Payments (1.2 ) — (6.1 ) (0.1 ) (1.1 ) (8.5 ) Impact of foreign currency and other — — (0.3 ) — (0.2 ) (0.5 ) Balance, September 30, 2018 $ 9.1 $ — $ 3.5 $ 0.2 $ 0.5 $ 13.3 ________________________________ (1) Asset impairment charges of $4.5 million for the nine months ended September 30, 2018 related to the 2017 and 2018 Plans are recorded as a reduction to "Properties and equipment, net" in the accompanying unaudited Consolidated Balance Sheets. These expenses are not recorded to the restructuring liability and therefore, are not included in the table above. Repositioning Expenses Repositioning Expenses - 2017 Plan and 2018 Plan Repositioning expenses associated with the 2017 and 2018 Plans are primarily related to consulting, other professional services and recruitment costs associated with the Company’s organizational realignment and advancing its technology strategy. Due to the scope and complexity of the Company’s repositioning activities, the range of estimated repositioning expense and capital expenditures could increase or decrease and the timing of incurrence could change. During the three and nine months ended September 30, 2018, GCP incurred repositioning expenses of $2.6 million related to the 2018 Plan. During the nine months ended September 30, 2018, the Company did no t make any cash payments related to such repositioning expenses. During the three and nine months ended September 30, 2018 , GCP incurred repositioning expenses related to the 2017 Plan of $1.1 million and $3.2 million , respectively. During the three and nine months ended September 30, 2017, GCP incurred repositioning expenses of $1.1 million and $1.5 million , respectively, related to the 2017 Plan. During the nine months ended September 30, 2018, total cash payments related to such repositioning expenses were $10.0 million , which included $5.5 million for capital expenditures. Separation-Related Repositioning Expenses Post-Separation, GCP incurred expenses related to its transition to a stand-alone public company and completed these activities as of December 31, 2017. The Company did not incur any costs related to such activities during the three and nine months ended September 30, 2018 . Please refer to Note 10, "Restructuring and Repositioning Expenses" to the Company's Consolidated Financial Statements included in the 2017 Annual Report in the Form 10-K for further information. Separation-related repositioning expenses incurred for the three and nine months ended September 30, 2017 were as follows: Three Months Ended September 30, 2017 Nine Months Ended September 30, 2017 (In millions) Professional fees $ — $ 3.4 Software and IT implementation fees — 0.9 Employee-related costs — 1.0 Total $ — $ 5.3 Total cash payments for the nine months ended September 30, 2017 were $4.2 million for separation-related repositioning expenses and $1.9 million for capital-related expenditures. There were no such payments made during the three and nine months ended September 30, 2018.

Other Comprehensive (Loss) Inco

Other Comprehensive (Loss) Income	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Other Comprehensive (Loss) Income	Other Comprehensive (Loss) Income The following tables present the pre-tax, tax and after-tax components of GCP's other comprehensive (loss) income for the three and nine months ended September 30, 2018 and 2017 : Three Months Ended September 30, 2018 (In millions) Pre-Tax Amount Tax (Expense) After-Tax Amount Defined benefit pension and other postretirement plans $ 0.3 $ (0.1 ) $ 0.2 Currency translation adjustments (1) (9.1 ) — (9.1 ) Other comprehensive loss attributable to GCP shareholders $ (8.8 ) $ (0.1 ) $ (8.9 ) Nine Months Ended September 30, 2018 (In millions) Pre-Tax Amount Tax Benefit After-Tax Amount Defined benefit pension and other postretirement plans $ (0.5 ) $ 0.1 $ (0.4 ) Currency translation adjustments (1) (27.3 ) — (27.3 ) Gain from hedging activities 0.1 — 0.1 Other comprehensive loss attributable to GCP shareholders $ (27.7 ) $ 0.1 $ (27.6 ) Three Months Ended September 30, 2017 (In millions) Pre-Tax Amount Tax Expense After-Tax Amount Defined benefit pension and other postretirement plans $ (0.3 ) $ — $ (0.3 ) Currency translation adjustments (1) 46.2 — 46.2 Gain from hedging activities 0.8 (0.3 ) 0.5 Other comprehensive income attributable to GCP shareholders $ 46.7 $ (0.3 ) $ 46.4 Nine Months Ended September 30, 2017 (In millions) Pre-Tax Amount Tax Benefit After-Tax Amount Defined benefit pension and other postretirement plans $ (0.3 ) $ — $ (0.3 ) Currency translation adjustments (1) 63.0 — 63.0 Loss from hedging activities (0.1 ) — (0.1 ) Other comprehensive income attributable to GCP shareholders $ 62.6 $ — $ 62.6 (1) Currency translation adjustments did not have a corresponding tax effect. The following tables present the changes in accumulated other comprehensive loss, net of tax, for the nine months ended September 30, 2018 and 2017 : (In millions) Defined Benefit Pension and Other Postretirement Plans Currency Translation Adjustments Hedging Activities Total Balance, December 31, 2017 $ 0.4 $ (86.0 ) $ (0.1 ) $ (85.7 ) Other comprehensive (loss) income before reclassifications (0.4 ) (27.3 ) 0.2 (27.5 ) Amounts reclassified from accumulated other comprehensive (loss) income — — (0.1 ) (0.1 ) Current-period other comprehensive (loss) income (0.4 ) (27.3 ) 0.1 (27.6 ) Balance, September 30, 2018 $ — $ (113.3 ) $ — $ (113.3 ) (In millions) Defined Benefit Pension and Other Postretirement Plans Currency Translation Adjustments Hedging Activities Total Balance, December 31, 2016 $ 0.1 $ (147.7 ) $ — $ (147.6 ) Other comprehensive (loss) income before reclassifications (0.3 ) 63.0 (0.7 ) 62.0 Amounts reclassified from accumulated other comprehensive (loss) income — — 0.6 0.6 Net current-period other comprehensive (loss) income (0.3 ) 63.0 (0.1 ) 62.6 Balance, September 30, 2017 $ (0.2 ) $ (84.7 ) $ (0.1 ) $ (85.0 ) GCP is a global enterprise operating in over 35 countries with the local currency generally deemed to be the functional currency for accounting purposes. The currency translation adjustments reflect translation of the balance sheets valued in functional currencies to the U.S. dollar as of the end of each period presented and translation of revenues and expenses at average exchange rates for each period presented. As of June 30, 2018, GCP concluded that Argentina is a highly inflationary economy since the three-year cumulative inflation rates commonly used to evaluate Argentina’s inflation currently exceed 100% . As a result, GCP began accounting for its operations in Argentina as a highly inflationary economy effective July 1, 2018. Please refer to Note 1, "Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies" for further discussion of currency transaction of highly inflationary economies. Please refer to Note 6, "Pension Plans and Other Postretirement Benefit Plans," for a discussion of pension plans and other postretirement benefit plans.

Stock Incentive Plans

Stock Incentive Plans	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Incentive Plans	Stock Incentive Plans GCP grants stock options, restricted stock units (the "RSUs") and performance-based units (the "PBUs") with or without market conditions which vest upon the satisfaction of a performance condition and/or a service condition. Please refer to Note 13, "Stock Incentive Plans" to the Company's Consolidated Financial Statements included in the 2017 Annual Report in the Form 10-K for further information on these awards. Stock-Based Compensation Accounting In accordance with U.S. GAAP, GCP estimates the fair value of equity awards issued at the grant date. The fair value of the awards is recognized as stock-based compensation expense on a straight line basis, net of estimated forfeitures, over the employee’s requisite service period for each separately vesting portion of the award. Total stock-based compensation (benefit) expense related to cash and non-cash settled awards is included in "Income (loss) from continuing operations before income taxes" in the accompanying unaudited Consolidated Statements of Operations and was $(0.3) million and $4.6 million , respectively, for the three and nine months ended September 30, 2018 and $2.0 million and $7.7 million , respectively, for the three and nine months ended September 30, 2017 . During the three months ended September 30, 2018, the Company recorded a stock-based compensation expense reduction of $2.8 million related to remeasurement of PBUs granted in 2017 based on their estimated expected payout at the end of the applicable performance period. For further information with regards to the valuation of PBUs, please refer to Note 13, “Stock Incentive Plans,” the Company’s Consolidated Financial Statements included in the 2017 Annual Report on Form 10-K. The Company issues new shares of common stock upon exercise of stock options. In accordance with certain provisions of the GCP Equity and Incentive Plan (the "Plan"), GCP repurchases shares issued to certain holders of GCP awards in order to fulfill statutory tax withholding requirements for the employee. During the nine months ended September 30, 2018 and 2017, GCP repurchased approximately 45,000 shares and 37,000 shares, respectively, under the provisions of the Plan. These purchases are reflected as "Share Repurchases" in the accompanying unaudited Consolidated Statements of Equity (Deficit). As of September 30, 2018 , approximately 8.3 million shares of common stock were reserved and available for future grant under the Plan. Stock Options Stock options are non-qualified and granted at exercise prices not less than 100% of fair market value on the grant date. The awards issued before February 28, 2017 were granted at the exercise price equal to fair market value on the grant date determined as the average of the high market price and low market price of the Company’s stock from that trading day. The awards issued after February 28, 2017 were granted at the exercise price equal to fair market value on the grant date determined as the market closing price of the Company’s stock on that date . Stock option awards that relate to Grace stock options originally granted prior to the Separation have a contractual term of five years from the original date of grant. Stock option awards granted post-Separation have a contractual term of seven or ten years from the original date of grant. Generally, stock options vest in substantially equal amounts each year over three years from the date of grant. GCP values stock options using the Black-Scholes option pricing model for estimating the fair value of options granted. For further information with regards to the valuation of stock options, please refer to Note 13, “Stock Incentive Plans,” the Company’s Consolidated Financial Statements included in the 2017 Annual Report on Form 10-K. The following summarizes GCP's assumptions for estimating the fair value of stock options granted during 2018 and 2017 : Nine Months Ended September 30, Assumptions used to calculate expense for stock options: 2018 2017 Risk-free interest rate 2.68-2.90% 1.83 - 2.10% Average life of options (years) 5.5-6.5 5.5 - 6.5 Volatility 27.91-30.65% 31.42 - 31.96% Dividend yield — — Weighted average fair value per stock option $10.63 $9.16 The following table sets forth information relating to stock options denominated in GCP stock during the nine months ended September 30, 2018 : Stock Option Activity Number Of Weighted Weighted Aggregated Outstanding, December 31, 2017 1,636 $ 18.94 3.78 $ 21,597 Options exercised 314 16.76 Options forfeited/expired/canceled 25 25.41 Options granted 241 31.31 Outstanding, September 30, 2018 1,538 $ 21.21 3.99 $ 9,262 Exercisable, September 30, 2018 968 $ 18.87 2.79 $ 7,339 Vested and expected to vest, September 30, 2018 1,520 $ 21.15 3.96 $ 9,222 The aggregate intrinsic values in the table above represent the total pre-tax intrinsic value, determined as the difference between GCP's closing stock price on the last trading day of September 30, 2018 and the exercise price, multiplied by the number of in-the-money options that would have been received by the option holders had all option holders exercised their in-the-money options at period end. The amount changes based on the fair market value of GCP's stock. Total intrinsic value of all options exercised during the three and nine months ended September 30, 2018 was $0.1 million , and $4.8 million , respectively, and during the three and nine months ended September 30, 2017 was $0.2 million and $8.3 million , respectively. At September 30, 2018 , total unrecognized stock-based compensation expense for stock options outstanding was $1.3 million and is expected to be recognized over the weighted-average period of approximately 1.0 year. Restricted Stock Units and Performance Based Units RSUs and PBUs are granted with the exercise price equal to zero and are converted to shares immediately upon vesting. As of September 30, 2018 , $6.3 million of total unrecognized compensation expense related to the RSU and PBU awards is expected to be recognized over the remaining weighted-average service period of approximately 1.2 years. RSUs The Company grants RSUs which are time-based, non-performance units. RSUs generally vest over a three year period, with some awards vesting in substantially equal amounts each year over three years and some awards vesting 100% after the third year from the date of grant. A smaller number of RSUs were designated as sign-on awards which are used for the purposes of attracting key employees and covering outstanding awards from prior employers. Such awards vest 100% after two years from the date of grant . RSUs are recorded at fair value on the date of grant. The common stock-settled awards are considered equity awards, with the stock compensation expense being determined based on GCP’s stock price on the grant date. The cash settled awards are considered liability awards, with the liability being remeasured each reporting period based on GCP’s then current stock price. GCP’s RSU activity for the nine months ended September 30, 2018 is presented below: RSU Activity Number Of Weighted Outstanding, December 31, 2017 406 $ 19.15 RSUs settled 158 18.36 RSUs forfeited 10 27.97 RSUs granted 129 29.28 RSUs outstanding, September 30, 2018 367 $ 22.83 During the nine months ended September 30, 2018 , GCP distributed 115,932 shares and $1.2 million of cash to settle RSUs upon vesting. GCP expects all future RSU vestings to settle in stock. PBUs PBUs are performance-based units which are granted by the Company either with or without market conditions. Such PBUs are expected to cliff vest over three years and will be settled in GCP common stock. PBUs are remeasured during each reporting period based on their expected payout, which may range from 0% to 200% of the targets for such awards. Therefore, the stock-based compensation expense recognized for these awards during each reporting period is subject to volatility until the final payout target is determined at the end of the applicable performance period. Beginning with the annual PBU grant in the first quarter of 2017, the performance criteria for PBUs included a 3 -year cumulative adjusted diluted earnings per share metric that is modified, up or down, based on the Company's relative total shareholder return ("TSR") against the Russell 3000 Index ("the Index"). The number of shares that ultimately vest, if any, is based on Company performance against these metrics, and can range from 0% to 200% of the target number of shares granted to the employee. The 2018 and 2017 awards will become vested, if at all, three years from the grant date once actual performance is certified by the Board's Compensation Committee. Vesting is also subject to the employees' continued employment through the vesting date. PBUs granted during the three and nine months ended September 30, 2018 and 2017 were valued using a Monte Carlo simulation, which is commonly used for assessing the grant date fair value of equity awards with relative TSR metrics. For further information with regards to the valuation of PBUs, please refer to Note 13, “Stock Incentive Plans,” the Company’s Consolidated Financial Statements included in the 2017 Annual Report on Form 10-K. The following summarizes the assumptions used in the Monte Carlo simulations for estimating the grant date fair values of PBUs granted during the nine months ended September 30, 2018 and 2017: Nine Months Ended September 30, Assumptions used to calculate expense for PBUs: 2018 2017 Expected Term (Remaining Performance Period) 2.86 2.84 Expected volatility 28.56% 28.00% Risk-free interest rate 2.38% 1.41% Expected dividends — — Correlation coefficient 38.98% 46.83% Average correlation coefficient of constituents 39.96% 42.33% During the nine months ended September 30, 2018 , GCP granted 149,974 PBUs to Company employees. The weighted average grant date fair value of PBUs granted during the nine months ended September 30, 2018 was $34.20 . During the nine months ended September 30, 2018 , 3,369 of these PBUs were forfeited. PBUs that were granted during the year ended December 31, 2017 to Company employees remain outstanding as of September 30, 2018 and the weighted average grant date fair value was $28.29 . During the nine months ended September 30, 2018 , 8,897 of these PBUs were forfeited. PBUs that were granted during the year ended December 31, 2016 to Company employees remain outstanding as of September 30, 2018 and the weighted average grant date fair value of these awards was $17.04 . During the nine months ended September 30, 2018 , none of these awards were forfeited.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The following table shows a reconciliation of the numerators and denominators used in calculating basic and diluted earnings (loss) per share: Three Months Ended September 30, Nine Months Ended September 30, (In millions, except per share amounts) 2018 2017 2018 2017 Numerators Income (loss) from continuing operations attributable to GCP shareholders $ 7.2 $ (18.1 ) $ (35.8 ) $ (41.8 ) Income from discontinued operations, net of income taxes 18.2 677.3 26.7 679.4 Net income (loss) attributable to GCP shareholders $ 25.4 $ 659.2 $ (9.1 ) $ 637.6 Denominators Weighted average common shares—basic calculation 72.2 71.6 72.1 71.2 Dilutive effect of employee stock awards (1) 0.5 — — — Weighted average common shares—diluted calculation 72.7 71.6 72.1 71.2 Basic earnings (loss) per share Income (loss) from continuing operations attributable to GCP shareholders $ 0.10 $ (0.25 ) $ (0.50 ) $ (0.59 ) Income from discontinued operations, net of income taxes $ 0.25 $ 9.46 $ 0.37 $ 9.54 Net income (loss) attributable to GCP shareholders (2) $ 0.35 $ 9.21 $ (0.13 ) $ 8.96 Diluted earnings (loss) per share Income (loss) from continuing operations attributable to GCP shareholders $ 0.10 $ (0.25 ) $ (0.50 ) $ (0.59 ) Income from discontinued operations, net of income taxes $ 0.25 $ 9.46 $ 0.37 $ 9.54 Net income (loss) attributable to GCP shareholders (2) $ 0.35 $ 9.21 $ (0.13 ) $ 8.96 ________________________________ (1) Dilutive effect not applicable to periods in which GCP generated a loss from continuing operations. (2) Amounts may not sum due to rounding. GCP uses the treasury stock method to compute diluted earnings (loss) per share. During the three months ended September 30, 2018, 0.4 million of anti-dilutive stock awards were excluded from the computation of diluted earnings per share based on the treasury stock method as a result of an income from continuing operations generated during the period then ended. During the nine months ended September 30, 2018 and the three and nine months ended September 30, 2017, there were no anti-dilutive shares based on the treasury stock method as a result of a loss from continuing operations incurred during the periods then ended. As of September 30, 2018, total outstanding options of 1.5 million and total outstanding RSUs of 0.4 million were excluded from the computation of diluted loss per share during the nine months ended September 30, 2018. Additionally, as of September 30, 2017, total outstanding options of 1.7 million and total outstanding RSUs of 0.4 million were excluded from the computation of diluted loss per share during the three and nine months ended September 30, 2017 . The following table summarizes options and RSUs excluded from dilutive shares and diluted loss per share shown in the table above: Three Months Ended September 30, Nine Months Ended September 30, (In millions of shares) 2018 2017 2018 2017 Dilutive effect: Options (1) N/A 0.6 0.5 0.7 RSUs (1) N/A 0.4 0.2 0.4 ________________________________ (1) N/A - Dilutive effect is included in computation of diluted earnings per share under the treasury stock method for periods in which GCP generated income from continuing operations. During the nine months ended September 30, 2018 and 2017 , GCP repurchased approximately 45,000 and 37,000 shares of Company common stock for $1.3 million and $1.0 million , respectively, in connection with its equity compensation programs.

Related Party Transactions and

Related Party Transactions and Transactions with Grace	9 Months Ended
	Sep. 30, 2018
Related Party Transactions [Abstract]
Related Party Transactions and Transactions with Grace	Related Party Transactions and Transactions with Grace Transition Services Agreement In connection with the Separation, the Company and Grace entered into a transition services agreement pursuant to which GCP and Grace provided various services to each other on a transitional basis which ended during the third quarter of 2017. During the three and nine months ended September 30, 2018 there were no services rendered between GCP and Grace. Please refer to Note 12, "Related Party Transactions and Transactions with Grace," to the Company's Consolidated Financial Statements included in the 2017 Annual Report in the Form 10-K for further information regarding the transaction services agreement. Tax Sharing Agreement In connection with the Separation, the Company and Grace entered into a Tax Sharing Agreement which governs the parties’ respective rights, responsibilities and obligations with respect to tax liabilities and benefits, tax attributes, the preparation and filing of tax returns, the control of audits and other tax proceedings, and other matters regarding taxes. In general, and subject to the terms of the Tax Sharing Agreement, GCP is responsible for all U.S. federal, state and foreign taxes (and any related interest, penalties or audit adjustments) reportable on a GCP separate return (a return that does not include Grace or any of its subsidiaries); and Grace is responsible for all U.S. federal, state and foreign income taxes (and any related interest, penalties or audit adjustments) reportable on a consolidated, combined or unitary return that includes Grace or any of its subsidiaries and GCP or any of its subsidiaries up to the Separation date. GCP has recorded $7.2 million of indemnified receivables in "Other assets" as of September 30, 2018 and December 31, 2017. GCP has recorded $2.2 million and $2.7 million , respectively, of indemnified payables in "Other current liabilities" as of September 30, 2018 and December 31, 2017. In addition, the Tax Sharing Agreement imposes certain restrictions on GCP and its subsidiaries (including restrictions on share issuances, business combinations, sales of assets and similar transactions) that are designed to preserve the qualification of the Distribution, together with certain related transactions, under Section 355 and certain other relevant provisions of the Code. The Tax Sharing Agreement provides special rules that allocate tax liabilities in the event the Distribution, together with certain related transactions, does not so qualify. In general, under the Tax Sharing Agreement, each party is expected to be responsible for any taxes imposed on, and certain related amounts payable by, GCP or Grace that arise from the failure of the Distribution and certain related transactions, to qualify under Section 355 and certain other relevant provisions of the Code, to the extent that the failure to so qualify is attributable to actions, events or transactions relating to such party’s respective stock, assets or business, or a breach of the relevant representations or covenants made by such party in the Tax Sharing Agreement.

Operating Segment and Geographi

Operating Segment and Geographic Information	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Operating Segment and Geographic Information	Operating Segment and Geographic Information GCP is engaged in the production and sale of specialty construction chemicals and specialty building materials through two operating segments. Specialty Construction Chemicals operating segment manufactures and markets concrete admixtures and cement additives. Specialty Building Materials operating segment manufactures and markets sheet and liquid membrane systems that protect structures from water, air and vapor penetration, as well as fireproofing and other products designed to protect the building envelope. Operating Segment Data The following table presents information related to GCP's operating segments: Three Months Ended September 30, Nine Months Ended September 30, (In millions) 2018 2017 2018 2017 Net Sales Specialty Construction Chemicals $ 165.4 $ 156.2 $ 487.4 $ 449.1 Specialty Building Materials 130.9 126.2 361.9 345.8 Total net sales $ 296.3 $ 282.4 $ 849.3 $ 794.9 Segment Operating Income Specialty Construction Chemicals segment operating income $ 12.7 $ 15.7 $ 31.2 $ 44.5 Specialty Building Materials segment operating income 34.3 30.1 84.2 80.6 Total segment operating income $ 47.0 $ 45.8 $ 115.4 $ 125.1 Reconciliation of Operating Segment Data to Financial Statements Corporate expenses directly related to the operating segments are allocated to the segment's operating income. GCP excludes from the segments' operating income certain functional costs, certain impacts of foreign currency exchange (related primarily to Venezuela for periods up through the deconsolidation date of July 3, 2017, as discussed in Note 1, "Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies"), as well as other corporate costs included in the table below. GCP also excludes from the segment's operating income certain ongoing defined benefit pension costs recognized during each reporting period, which include service and interest costs, the effect of expected returns on plan assets and amortization of prior service costs/credits. GCP believes that the exclusion of certain corporate costs and pension costs provides a better indicator of its operating segment performance since such costs are not managed at an operating segment level. Total segment operating income for the three and nine months ended September 30, 2018 and 2017 , is reconciled below to " Income (loss) from continuing operations before income taxes " presented in the accompanying unaudited Consolidated Statements of Operations: Three Months Ended September 30, Nine Months Ended September 30, (In millions) 2018 2017 2018 2017 Total segment operating income $ 47.0 $ 45.8 $ 115.4 $ 125.1 Corporate costs (1) (5.3 ) (7.5 ) (22.8 ) (28.9 ) Certain pension costs (2.0 ) (2.1 ) (5.8 ) (7.0 ) Loss on sale of product line — — — (2.1 ) Currency and other financial losses in Venezuela — (36.7 ) — (39.1 ) Litigation settlement — (4.0 ) — $ (4.0 ) Repositioning expenses (3.7 ) (1.1 ) (5.8 ) $ (6.8 ) Restructuring expenses and asset impairments (14.3 ) (2.1 ) (13.2 ) $ (13.0 ) Pension MTM adjustment and other related costs, net — (3.0 ) (0.9 ) $ (2.9 ) Gain on termination and curtailment of pension and other postretirement plans — 0.8 0.1 $ 5.9 Third-party and other acquisition-related costs (0.5 ) (2.0 ) (2.1 ) $ (5.0 ) Amortization of acquired inventory fair value adjustment — (0.2 ) (0.2 ) $ (2.9 ) Tax indemnification adjustments — — — (2.4 ) Net income attributable to noncontrolling interests 0.1 0.1 0.3 0.2 Other financing costs — (6.0 ) — (6.0 ) Interest expense, net (2) (5.3 ) (14.5 ) (83.6 ) (49.0 ) Currency losses in Argentina (1.1 ) — (1.1 ) — Income (loss) from continuing operations before income taxes $ 14.9 $ (32.5 ) $ (19.7 ) $ (37.9 ) _______________________________ (1) Management allocates corporate costs to each segment to the extent such costs are directly attributable to the segments. Corporate costs include approximately $5.4 million of allocated costs during the nine months ended September 30, 2017 that were previously reported within the Darex operating segment since such costs did not meet the criteria to be reclassified to discontinued operations. Beginning with the third quarter of 2017, the Company began allocating these costs to its remaining operating segments. (2) Interest expense, net includes a loss of $59.8 million as a result of debt refinancing transaction completed on April 10, 2018. Please refer to Note 4, "Debt and Other Borrowings" for further information on the transaction. Disaggregation of Total Net Sales The Company disaggregates its revenue from contracts with customers by operating segments, which it believes best depicts how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors. Geographic Area Data The table below presents information related to the geographic areas in which GCP operates. Sales are attributed to geographic areas based on customer location. Three Months Ended September 30, Nine Months Ended September 30, (In millions) 2018 2017 2018 2017 Net Sales United States $ 144.4 $ 132.5 $ 402.4 $ 374.2 Canada and Puerto Rico 9.7 9.0 24.0 21.8 Total North America 154.1 141.5 426.4 396.0 Europe Middle East Africa 61.7 67.0 189.2 178.9 Asia Pacific 63.9 58.0 181.6 168.4 Latin America 16.6 15.9 52.1 51.6 Total $ 296.3 $ 282.4 $ 849.3 $ 794.9

Discontinued Operations

Discontinued Operations	9 Months Ended
	Sep. 30, 2018
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	Discontinued Operations On July 3, 2017, the Company completed the sale of Darex to Henkel for $1.06 billion in cash (the “Disposition”). In accordance with applicable accounting guidance, the assets and liabilities of the Darex business in the delayed close countries are categorized as "Assets held for sale" or "Liabilities held for sale" in the accompanying unaudited Consolidated Balance Sheets as of September 30, 2018 and December 31, 2017. In addition, Darex results have been reclassified and reflected as "discontinued operations" in the accompanying unaudited Consolidated Statements of Operations and accompanying unaudited Consolidated Statements of Cash Flows for all periods presented. The agreement with Henkel governing the Disposition (the “Amended Purchase Agreement”) provides for a series of delayed closings in certain non-U.S. jurisdictions, including Argentina, China, Colombia, Indonesia, Peru and Venezuela for which sale proceeds were received on the July 3, 2017 closing date. The delayed closings will implement the legal transfer of the Darex business in the delayed closing jurisdictions in accordance with local law. The delayed closings in Argentina, Colombia, and Peru were completed during the first half of 2018. During the three months ended September 30, 2018, the delayed closing in China was completed. During the three and nine months ended September 30, 2018, the Company recorded an after-tax gain of $18.8 million and $29.1 million , respectively, on the sale of the delayed close entities in these countries. During each of the three and nine months ended September 30, 2017, the Company recorded an after-tax gain of $683.7 million on the sale of the Darex entities that closed on July 3, 2017. The remaining delayed closings in Indonesia and Venezuela are expected to be completed over the following 4 to 15 months. Up to the time of the delayed closings for these countries, the results of the operations of the Darex business in the delayed close countries are reported as “Income from discontinued operations, net of income taxes” in the accompanying unaudited Consolidated Statements of Operations and reflect an economic benefit payable to or recoverable from Henkel, as applicable for each reporting period. As of December 31, 2017, a liability of $55.1 million and $13.6 million , respectively, related to the consideration received by GCP for the delayed closings was recognized in “Other current liabilities” and “Other liabilities." During the nine months ended September 30, 2018 , GCP reduced the liability by $55.1 million which consisted primarily of the sale proceeds received on July 3, 2017 for the delayed closings in Argentina, Colombia, Peru, and China completed during the period then ended. The remaining liability of $13.1 million and $0.5 million , respectively, for the consideration received on the closing date related to the remaining delayed closing countries is recorded in “Other current liabilities” and "Other liabilities" as of September 30, 2018 . The following table includes a reconciliation of the gain on the sale of the Darex business related to delayed close entities recorded during the three and nine months ended September 30, 2018 and September 30, 2017: Three Months Ended September 30, Nine Months Ended September 30, (In millions) 2018 2017 2018 2017 Net proceeds included in gain $ 30.4 $ 1,000.2 $ 55.4 $ 1,000.2 Less: Transaction costs — 15.9 — 15.9 Less: Net assets derecognized 5.4 100.6 11.9 100.6 Gain recognized before income taxes 25.0 883.7 43.5 883.7 Less: Tax effect of gain recognized 6.2 200.0 14.4 200.0 Gain recognized after income taxes $ 18.8 $ 683.7 $ 29.1 $ 683.7 In connection with the Disposition and related tax gain, as noted above, the Company recorded tax expense of $6.2 million and $14.4 million , respectively, within discontinued operations during the three and nine months ended September 30, 2018 and $200.0 million during the three and nine months ended September 30, 2017. The tax consequences of the Disposition are complex and the calculation of the provision is based on management’s best estimate using all readily accessible information. Management is in the process of completing further analysis related to the stock basis, earnings and profits, tax pools, transaction costs and other related components associated with the Disposition. Based on the overall complexity of the calculation, management believes that there is a reasonable possibility that differences between the estimated tax provision and actual outcome may result within the next three months, which could have a material impact on the Company's results of operations. In connection with the Disposition, the Company and Henkel also entered into a Transition Services Agreement pursuant to which Henkel and the Company will provide various services to each other in connection with the transition of the Darex business to Henkel. The Company and Henkel expect to perform these services, which relate to real estate, information technology, accounts payable, payroll and other financial functions and administrative services, for various periods up to 24 months following the closing date. The charges for such services generally allow the servicing party to recover all out-of-pocket costs and expenses and are recorded in "Other income, net" on the accompanying unaudited Consolidated Statements of Operations. Additionally, in connection with the Disposition, the Company and Henkel entered into a Master Tolling Agreement, whereby Henkel will operate certain equipment at facilities being sold in order to manufacture and prepare for shipping certain products related to product lines that the Company continues to own. The Company and Henkel expect these services to be provided for a period of 24 months following the closing date. Under the Amended Purchase Agreement, GCP is required to indemnify Henkel for certain possible future tax liabilities. GCP has recorded an indemnification payable of $3.2 million and $3.3 million , respectively, in this regard as a result of the Disposition as of September 30, 2018 and December 31, 2017. The components of "Income from discontinued operations, net of income taxes" in the accompanying unaudited Consolidated Statements of Operations are comprised of the following: Three Months Ended September 30, Nine Months Ended September 30, (In millions) 2018 2017 2018 2017 Net sales $ 1.7 $ 9.1 $ 13.3 $ 156.9 Cost of goods sold 1.2 6.0 13.9 104.6 Gross profit 0.5 3.1 (0.6 ) 52.3 Selling, general and administrative expenses 1.3 6.6 4.6 40.1 Research and development expenses — 0.1 — 2.3 Restructuring and asset impairments — 0.4 0.8 6.9 Gain on sale of business (25.0 ) (883.7 ) (43.5 ) (883.7 ) Other (income) expenses, net (0.1 ) 2.4 (3.2 ) 7.5 Total income (23.8 ) (874.2 ) (41.3 ) (826.9 ) Income from discontinued operations before income taxes 24.3 877.3 40.7 879.2 Provision for income taxes (6.1 ) (200.0 ) (14.0 ) (199.7 ) Less: Net income attributable to noncontrolling interests — — — (0.1 ) Income from discontinued operations, net of income taxes $ 18.2 $ 677.3 $ 26.7 $ 679.4 The carrying amounts of the major classes of assets and liabilities of Darex classified as held for sale in the accompanying unaudited Consolidated Balance Sheets as of September 30, 2018 and December 31, 2017 consist of the following: (In millions) September 30, 2018 December 31, 2017 Trade accounts receivable $ 1.7 $ 8.4 Inventories 1.4 10.6 Other current assets — 0.7 Current assets held for sale $ 3.1 $ 19.7 Properties and equipment, net 0.4 2.2 Other assets 0.5 0.6 Non-current assets held for sale $ 0.9 $ 2.8 Accounts payable 1.1 6.4 Other current liabilities 0.1 1.4 Current liabilities held for sale $ 1.2 $ 7.8 Underfunded and unfunded defined benefit pension plans 0.3 0.3 Non-current liabilities held for sale $ 0.3 $ 0.3

Acquisitions and Dispositions

Acquisitions and Dispositions	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Acquisitions and Dispositions	Acquisitions and Dispositions Acquisitions Completed in 2018 Clydebridge Holdings Limited On May 4, 2018, GCP acquired 100% of the outstanding capital stock of Clydebridge Holdings Limited which owns 100% of RIW Limited (the "RIW"), a U.K.-based supplier of waterproofing solutions for commercial and residential construction applications. The acquisition is expected to strengthen GCP’s position in the U.K. waterproofing market and complement its product portfolio within the SBM operating segment by adding waterproofing capabilities for a wider range of projects. The aggregate purchase price of $29.7 million , net of cash acquired of $10.0 million , consisted of a net cash payment of $29.8 million , which was reduced by working capital adjustments of $0.1 million . The purchase price is subject to normal and customary purchase price adjustments. The Company accounted for the acquisition as a business combination in accordance with provisions of ASC 805, Business Combinations ("ASC 805"). The operating results of RIW have been reflected in the results of operations for the SBM operating segment from the date of the acquisition. The Company used a market participant approach to record the assets acquired and liabilities assumed in the RIW acquisition. The purchase price allocation is based on a preliminary valuation and is subject to further adjustments within the measurement period as additional information becomes available related to the fair value of such assets acquired and liabilities assumed. The fair values of inventory, intangible assets, accrued liabilities, tax-related matters and residual goodwill were preliminary as of September 30, 2018. The Company will refine such fair value estimates as new information becomes available during the measurement period. Any adjustments to the purchase price allocation will be made as soon as practicable, but no later than one year from the acquisition date. The following table summarizes the updated allocation of the purchase price as of September 30, 2018: (In millions) Net Assets Acquired Accounts receivable (approximates contractual value) $ 1.3 Inventories 0.6 Prepaid expenses and other current assets 0.1 Property, plant and equipment 0.1 Intangible assets 10.7 Goodwill 19.9 Accounts payable (1.0 ) Accrued liabilities (0.1 ) Deferred tax liabilities (1.9 ) Net assets acquired $ 29.7 Fair values of intangible assets acquired consisted of customer relationships of $8.8 million , trademarks and trade names of $1.1 million , as well as developed technology of $0.8 million . The Company used the income approach in accordance with the excess-earnings method to estimate the fair value of customer relationships, equal to the present value of the incremental after-tax cash flows attributable to the intangible asset. The Company used the income approach in accordance with the relief-from-royalty method to estimate the fair values of the trademarks and trade names, as well as developed technology which is equal to the present value of the after-tax royalty savings attributable to owning the intangible asset. The weighted average amortization periods for the intangible assets acquired are 9 years for the customer relationship intangible asset, 15 years for developed technology and 10 years for trademarks and trade names. The total weighted average amortization period of the intangible assets acquired is 10 years using methods that approximate the pattern in which the economic benefits are expected to be realized. At the closing of the acquisition of RIW, a portion of the consideration was placed into escrow which was ascribed to the purchase price and will be released to the sellers no later than December 30, 2020. The escrow was related to the sellers’ satisfaction of indemnity claims and general representations and warranties. There were no amounts released from the escrow to the sellers as of September 30, 2018. Goodwill represents the excess of the consideration transferred over the fair value of the net assets acquired and has been assigned to the SBM operating segment. Goodwill is primarily the result of expected synergies from combining the operations of RIW with GCP's operations and is not deductible for tax purposes. The Company did not present a proforma information summary for its consolidated results of operations for three and nine months ended September 30, 2018 as if the acquisition of RIW occurred on January 1, 2017 because such results were not material. Acquisitions Completed in 2017 Ductilcrete Technologies On October 31, 2017, GCP acquired 100% of the share capital of Ductilcrete, a U.S.-based technology leader for concrete engineered systems, for a total cash consideration of $31.8 million , net of $ 1.5 million of cash acquired. The Company believes that the acquisition of Ductilcrete expands its technology platform with new product categories and engineered systems that will allow it to access a wider range of customers. The Company accounted for the acquisition as a business combination in accordance with provisions of ASC 805, and reflected Ductilcrete's operating results from the date of the acquisition within the operating results of the SCC operating segment. The Company allocated the acquisition purchase price to the assets acquired and liabilities assumed determined from a market participant perspective and recognized the excess as goodwill. Please refer to Note 16, "Acquisitions and Dispositions," to the Company's Consolidated Financial Statements included in the 2017 Annual Report on Form 10-K for further information on this acquisition. The Company allocated the acquisition purchase price to the assets acquired and liabilities assumed determined from a market participant perspective and recognized the excess as goodwill. As of December 31, 2017, the Company recognized $14.0 million of goodwill, which is tax-deductible and will be amortized for tax purposes over 15 years. The goodwill is attributable to the revenue growth and operating synergies that GCP expects to realize from this acquisition. During the first quarter of 2018, the Company finalized certain closing adjustments with the seller and its purchase price allocation by recording a $0.3 million reduction in both consideration paid and accounts receivable. The following table presents the aggregate purchase price allocation as of September 30, 2018: (In millions) Net Assets Acquired Accounts receivable $ 2.2 Other current assets 0.2 Properties and equipment 0.1 Goodwill 14.0 Intangible assets 15.5 Accounts payable (0.2 ) Net assets acquired $ 31.8 Stirling Lloyd On May 17, 2017, GCP acquired 100% of the share capital of Stirling Lloyd, a UK-based global supplier of high-performance liquid waterproofing and coatings products, for total consideration of $91.1 million , net of $16.1 million of cash acquired. The Company believes that the addition of Stirling Lloyd and its products, which are used for the protection of infrastructure and buildings, opens new growth opportunities by offering additional selling channels for specialized end-market applications. The Company accounted for the acquisition as a business combination in accordance with provisions of ASC 805, and reflected Stirling Lloyd's operating results from the date of the acquisition within the operating results of the SBM operating segment. The Company allocated the acquisition purchase price to the assets acquired and liabilities assumed determined from a market participant perspective and recognized the excess as goodwill. During 2017, the Company finalized its purchase price allocation. Please refer to Note 16, "Acquisitions and Dispositions" to the Company's Consolidated Financial Statements included in the 2017 Annual Report on Form 10-K for further information on this acquisition. Revenue from RIW, Ductilcrete and Stirling Lloyd was not material individually, or in the aggregate, to the Company's consolidated revenue during the three and nine months ended September 30, 2018. Net income from RIW, Ductilcrete and Stirling Lloyd was not material individually to the Company’s consolidated net income (loss) during the three and nine months ended September 30, 2018. In the aggregate, net income from RIW, Ductilcrete and Stirling Lloyd was $3.1 million and $8.1 million , respectively, during the three and nine months ended September 30, 2018. Dispositions Disposal of Non-core Halex Net Assets In April 2017, the Company completed the sale of non-core carpet tack strip and plywood underlayment product lines that were acquired with Halex Corporation (“Halex”) for approximately $3 million in cash. The Company recorded a $2.1 million loss related to the disposal of these non-core Halex net assets, which is reflected in "Other income, net" in the accompanying unaudited Consolidated Statements of Operations.

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited Consolidated Financial Statements are presented on a consolidated basis and include all of the accounts and operations of GCP and its majority-owned subsidiaries, except as noted below with respect to the Company's Venezuela subsidiary. The financial statements reflect the financial position, results of operations and cash flows of GCP in accordance with generally accepted accounting principles in the United States of America ("GAAP") and the instructions to Form 10-Q and Article 10 of SEC Regulation S-X for interim financial information. The interim financial statements presented herein are unaudited and should be read in conjunction with the audited Consolidated Financial Statements and notes thereto contained in GCP's Annual Report on Form 10-K filed with the SEC for the year ended December 31, 2017 (the "2017 Annual Report on Form 10-K"). The accompanying Consolidated Balance Sheet as of December 31, 2017 was derived from the audited annual consolidated financial statements as of the period then ended. Certain information and footnote disclosures typically included in GCP's annual consolidated financial statements have been condensed or omitted. The accompanying unaudited financial statements reflect all adjustments that, in the opinion of management, are necessary for a fair statement of the results of the interim periods presented. All such adjustments are of a normal recurring nature except for the impacts of adopting new accounting standards discussed below. All significant intercompany accounts and transactions have been eliminated. The results of operations for the three and nine-months period ended September 30, 2018 are not necessarily indicative of the results of operations for the year ending December 31, 2018.
Discontinued Operations	Discontinued Operations As noted above, on July 3, 2017, the Company completed the sale of Darex to Henkel. In conjunction with this transaction and applicable GAAP, the assets and liabilities related to Darex in the applicable delayed close countries have been reclassified and reflected as "held for sale" in the accompanying unaudited Consolidated Balance Sheets as of September 30, 2018 and December 31, 2017, as discussed further in Note 15, "Discontinued Operations". Additionally, Darex results of operations and cash flows have been reclassified and reflected as "discontinued operations" in the accompanying unaudited Consolidated Statements of Operations and accompanying unaudited Consolidated Statements of Cash Flows for all periods presented. As of December 31, 2017, a liability of $55.1 million and $13.6 million , respectively, related to the consideration received by GCP for the delayed closings was recognized in “Other current liabilities” and “Other liabilities." During the nine months ended September 30, 2018 , GCP reduced the liability by $55.1 million which consisted primarily of the sale proceeds received on July 3, 2017 for the delayed closings in Argentina, Colombia, Peru, and China completed during the period then ended. The remaining liability of $13.1 million and $0.5 million , respectively, for the consideration received on the closing date related to the remaining delayed closing countries is recorded in “Other current liabilities” and "Other liabilities" as of September 30, 2018 . Unless otherwise noted, the information throughout the Notes to the accompanying unaudited Consolidated Financial Statements pertains only to the continuing operations of GCP. Please refer to Note 15, "Discontinued Operations" for further discussion of discontinued operations.
Principles of Combination	Deconsolidation of Venezuelan Operations Prior to July 3, 2017, the Company included the results of its Venezuelan operations (“GCP Venezuela”) in the Consolidated Financial Statements using the consolidation method of accounting. Venezuelan exchange control regulations have resulted in an other-than-temporary lack of exchangeability between the Venezuelan bolivar and U.S. dollar, and have restricted GCP Venezuela’s ability to pay dividends and meet obligations denominated in U.S. dollars. These exchange regulations, combined with other regulations, have constrained availability of raw materials and have significantly limited GCP Venezuela’s ability to maintain normal production. As a result of these conditions, combined with the loss of scale in Venezuela resulting from the sale of the Company’s Darex-related operations and assets in Venezuela, GCP has deconsolidated its Venezuelan operations as of July 3, 2017 in accordance with provisions of Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") 810, Consolidation. During the three months ended September 30, 2017, GCP recognized a pre-tax loss of $36.7 million which was $23.8 million after tax. Such loss is primarily related to unfavorable cumulative translation adjustments of $33.4 million associated with the Venezuelan business and presented as a “Loss in Venezuela” in the accompanying unaudited Consolidated Statements of Operations during the three and nine months ended September 30, 2017. Subsequent to July 3, 2017, the Company began accounting for GCP Venezuela using the cost method of accounting in accordance with which the Company’s financial results do not include the operating results of GCP Venezuela. The Company records cash and recognizes income from its Venezuelan operations in the accompanying unaudited Consolidated Financial Statements to the extent GCP is paid for inventory sold to or dividends are received from GCP Venezuela. The remaining investment on the Company's accompanying unaudited Consolidated Balance Sheets as of September 30, 2018 and December 31, 2017 is immaterial.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amount of assets and liabilities and disclosure of contingent assets and liabilities at the date of the unaudited Consolidated Financial Statements, and the reported amounts of revenues and expenses for the periods presented. Actual amounts could differ from those estimates, and the differences could be material. Changes in estimates are recorded in the period identified. GCP's accounting measurements that are most affected by management's estimates of future events are disclosed in its 2017 Annual Report on Form 10-K. There have been no significant changes to management's assumptions and estimates underlying those measurements as reported in these interim financial statements, except as discussed in Note 5, "Income Taxes".
Reclassifications	Reclassifications Certain amounts in prior period financial statements have been reclassified to conform to the current period presentation. Such reclassifications have not materially affected previously reported amounts.
Revision of Prior Period Financial Statements	Revision of Prior Period Financial Statements During the nine months ended September 30, 2018 GCP identified an error related to the presentation of the effect of currency exchange rate changes on cash and cash equivalents in its unaudited Consolidated Statements of Cash Flows filed in its Form 10-Q for the quarterly period ended September 30, 2017 and Consolidated Statements of Cash Flows in its 2017 Annual Report on Form 10-K for the year ended December 31, 2017. The correction of this error resulted in a reclassification between “cash provided by (used in) operating activities from continuing operations” and “effect of currency exchange rate changes on cash and cash equivalents” on the Consolidated Statements of Cash Flows filed during these periods. There was no impact on the Consolidated Statements of Operations, Consolidated Statements of Comprehensive Income, Consolidated Balance Sheets, or Consolidated Statements of Stockholders’ Equity during these periods as a result of these errors. The Company considered the guidance in ASC Topic 250, Accounting Changes and Error Corrections , ASC Topic 250-10-S99-1, Assessing Materiality , and ASC Topic 250-10-S99-2, Considering the Effects of Prior Year Misstatements when Quantifying Misstatements in Current Year Financial Statements in evaluating whether the Company’s previously issued consolidated financial statements were materially misstated. The Company concluded this error was not material individually or in the aggregate to the financial statements presented during any of the prior reporting periods, and therefore, amendments of previously filed Form 10-Q for the quarterly period ended September 30, 2017 and the 2017 Annual Report on Form 10-K for the year ended December 31, 2017 were not required. The revisions for these corrections to the applicable prior periods are reflected in the financial information herein and will be reflected in future filings containing such financial information. The following table summarizes the effects of the error on the interim and annual prior-period financial statements: Nine Months Ended, Year Ended, September 30, 2017 December 31, 2017 (in millions) As Previously Reported Adjustment As Revised As Previously Reported Adjustment As Revised CASH FLOWS FROM OPERATING ACTIVITIES: Net cash (used in) provided by operating activities from continuing operations $ (11.7 ) $ 2.6 $ (9.1 ) $ (5.4 ) $ 4.4 $ (1.0 ) Effect on currency exchange rate changes on cash and cash equivalents 4.0 (2.6 ) 1.4 6.4 (4.4 ) 2.0
Income Tax	Income Tax As a global enterprise, GCP is subject to a complex array of tax regulations and is required to make assessments of applicable tax laws and judgments in estimating its ultimate income tax liability. Please refer to Note 5, "Income Taxes," for further discussion regarding estimates used in accounting for income tax matters, including unrecognized tax benefits.
Currency Translation	Currency Translation Assets and liabilities of foreign subsidiaries (other than those located in countries with highly inflationary economies) are translated into U.S. dollars at current exchange rates, while revenues, costs and expenses are translated at average exchange rates during each reporting period. The resulting currency translation adjustments are included in "Accumulated other comprehensive loss" in the accompanying unaudited Consolidated Balance Sheets. The financial statements of any subsidiaries located in countries with highly inflationary economies are remeasured as if the functional currency were the U.S. dollar. Translation adjustments recognized as a result of such remeasurements are reflected in the results of operations in the unaudited Consolidated Statements of Operations. As of July 3, 2017, GCP deconsolidated its Venezuelan operations and, as a result, the Company's financial results no longer include the operations of GCP Venezuela, including currency translation adjustments, beyond that date. As of June 30, 2018, GCP concluded that Argentina is a highly inflationary economy since the three-year cumulative inflation rates commonly used to evaluate Argentina’s inflation currently exceed 100% . As a result, GCP began accounting for its operations in Argentina as a highly inflationary economy during the three months ended September 30, 2018. Effective July 1, 2018, the functional currency of the Company's subsidiary operating in Argentina became the U.S. dollar and all remeasurement adjustments after the effective date are reflected in GCP's results operations in the accompanying unaudited Consolidated Statements of Operations. During the three months ended September 30, 2018, the Company incurred losses of $1.1 million related to the remeasurement of these monetary net assets which are included in "Other income, net" in the accompanying unaudited Consolidated Statements of Operations. Net sales generated by the Argentina subsidiary were not material to the Company's consolidated net sales during the three and nine months ended September 30, 2018. Monetary net assets denominated in local currency within the Company's Argentina subsidiary were not material to GCP's consolidated total assets as of September 30, 2018.
Contract Assets and Contract Liabilities and Costs to Obtain a Contract	Contract Assets and Contract Liabilities Contract assets consist of unbilled amounts typically resulting from sales under long-term contracts when the revenue recognized exceeds the amount billed to the customer. Contract liabilities consist of advance payments and billings for revenue not meeting the criteria to be recognized and/or in excess of costs incurred. The Company’s contract assets and liabilities resulting from its contracts in the SCC or SBM operating segments were not material as of September 30, 2018 and December 31, 2017. Additionally, the amounts recorded in the accompanying unaudited Statements of Operations for the three and nine months ended September 30, 2018 related to changes in the contract assets and liabilities during the periods were immaterial. Trade accounts receivable include amounts billed and currently due from customers. The amounts due are stated at their net estimated realizable value. The Company maintains an allowance for doubtful accounts to provide for the estimated amount of receivables that will not be collected. The allowance is based upon an assessment of customer creditworthiness, historical payment experience, the age of outstanding receivables and collateral to the extent applicable. As of September 30, 2018 and December 31, 2017, the Company’s total trade accounts receivable balance was $213.1 million and $217.1 million , respectively, of which $5.0 million and $5.6 million , respectively, was related to trade accounts receivable associated with rental revenue generated from leases within certain SCC contracts and accounted for within the provisions of ASC Topic 840, Leases ("Topic 840"). Costs to Obtain a Contract GCP pays external sales agents certain commissions based on actual customer sales and it has determined that such amounts represent incremental costs incurred in obtaining such customer contracts. The performance obligations associated with these costs are satisfied at a point in time and accordingly the amortization period of such costs is less than one year. The Company expenses these costs as incurred in accordance with the practical expedient that allows for such treatment, as prescribed by ASC Topic 340-40, Costs to obtain or fulfill a contract .
Recently Issued/Adopted Accounting Standards	Recently Issued Accounting Standards Leases In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) , which is intended to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. In accordance with provisions of Topic 842, a lessee will be required to recognize in the statement of financial position a lease liability related to making lease payments and a right-of-use asset representing its right to use the underlying asset for the lease term, including optional payments that are reasonably certain to occur. In July 2018, the FASB issued two amendments to ASU 2016-02. The first amendment clarifies the application of certain aspects of ASU 2016-02 related to: (i) the rate implicit in the lease, (ii) impairment of the net investment in the lease, (iii) lessee reassessment of lease classification, (iv) lessor reassessment of lease term and purchase options, (v) variable payments that depend on an index or rate and (vi) certain transition adjustments, among other things. The second amendment includes a transition option allowing entities to forgo the application of ASU 2016-02 in the comparative periods presented in the financial statements during the year of adoption. Additionally, the amendment includes a practical expedient which provides lessors with an option to not separate non-lease components from the associated lease components when certain criteria are met and requires lessors to account for the combined component in accordance with provisions of ASC Topic 606 if the associated non-lease components are the predominant components in the arrangement. The guidance and the related amendments are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, with early adoption being permitted. GCP will adopt Topic 842 during the first quarter of 2019. As of September 30, 2018, GCP initiated the evaluation of the potential impact of adopting Topic 842 on its financial position, results of operations and related disclosures, but has not yet completed such assessment or determined whether it will elect the practical expedients upon adoption or the transition option allowing companies to forgo the application of Topic 842 in the comparative periods presented in its financial statements during the year of adoption. GCP has established a steering committee, a project plan and an implementation team which will analyze GCP's current contracts portfolio to determine the impact of adopting Topic 842 on the Company's financial position, results of operations and related disclosures. The implementation team is also responsible for evaluating and designing the necessary changes to the Company’s business processes, policies, systems and controls to support recognition and disclosure under the new guidance. During the three months ended September 30, 2018, GCP launched a comprehensive data collection initiative related to the population of arrangements containing leases and made a significant progress on collecting a portion of such data as of September 30, 2018. The Company also began the initial assessment of its lease contracts to determine the impact of adopting Topic 842 on its financial position, results of operations and related disclosures, but has not reached final conclusions related to such assessment as of September 30, 2018. Additionally, the Company completed a third party vendor selection process related to the lease accounting and management software solution to facilitate the adoption of Topic 842 and streamline the related accounting, contract tracking and disclosure reporting processes. Other new pronouncements issued but not effective until after September 30, 2018 are not expected to have a material impact on the Company's financial position, results of operations or liquidity. Recently Adopted Accounting Standards Revenue from Contracts with Customers In May 2014, the FASB issued Accounting Standards Update ("ASU") 2014-09, Revenue from Contracts with Customers (Topic 606). This update is intended to remove inconsistencies and weaknesses in revenue requirements; provide a more robust framework for addressing revenue issues; improve comparability of revenue recognition practices across entities, industries, jurisdictions and capital markets; provide more useful information to users of financial statements through improved disclosure requirements; and simplify the preparation of financial statements by reducing the number of requirements to which an entity must refer. The revised standard allows for two methods of adoption: (a) full retrospective adoption, in accordance with which the standard is applied to all periods presented, or (b) modified retrospective adoption, in accordance with which the cumulative effect of applying the new standard is recognized as an adjustment to the opening retained earnings balance. GCP has adopted Topic 606 effective January 1, 2018 using the modified retrospective approach. Under this transition method, GCP has elected to apply the guidance to all open contracts that are not completed or that are active as of January 1, 2018, and has elected not to retrospectively restate any of its contracts for modifications that occurred prior to the date of adoption of Topic 606. Accordingly, such modifications are reflected in the amounts reported for satisfied and unsatisfied performance obligations, transaction price of such performance obligations, and allocations of the transaction price among contract components, as of the date of the initial application. The impact of applying this practical expedient is immaterial to the Company’s accompanying unaudited Consolidated Financial Statements. The impact of the adoption of Topic 606 on the Company's three and nine months ended September 30, 2018 net sales, income (loss) from continuing operations before income taxes, and income (loss) from continuing operations was immaterial. The cumulative impact on the Company's retained earnings at January 1, 2018 was also not material. Such impact is disclosed in Note 2, "Revenue from Contracts with Customers." Stock Compensation In May 2017, the FASB issued ASU 2017-09, Compensation—Stock Compensation (Topic 718), which provides guidance related to the changes to the terms or conditions of a share-based payment award that require an application of modification accounting pursuant to Topic 718. GCP adopted the standard effective January 1, 2018; such adoption did not have a material impact on its financial position as of September 30, 2018 and results of operations for the three and nine months ended September 30, 2018. Statement of Cash Flows In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Payments, which addresses a number of specific cash flow presentation issues with the objective of reducing existing diversity in practice. GCP adopted the standard effective January 1, 2018 and classified within the cash flows from financing activities a $53.3 million payment related to the redemption premium on the extinguishment of its 9.5% Senior Notes, consistent with the provisions of the guidance. Such payment was included in "Repayments of long term note obligations" in the accompanying unaudited Consolidated Statements of Cash Flows. Please refer to Note 4, "Debt and Other Borrowings" for further discussion of this transaction. There was no other material impact on the Company's unaudited Consolidated Statements of Cash Flows for the nine months ended September 30, 2018 as a result of the standard adoption. Income Taxes In October 2016, the FASB issued ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory . This ASU requires recognition of the current and deferred income tax effects of an intra-entity asset transfer, other than inventory, when the transfer occurs, as opposed to current GAAP, which requires companies to defer the income tax effects until the asset has been sold to an outside party. GCP adopted the standard effective January 1, 2018. It did not have a material impact on the Company's financial position as of September 30, 2018 and results of operations for the three and nine months ended September 30, 2018. Other During the three and nine months ended September 30, 2018 , except as discussed above, there were no material changes to the Company's significant accounting and financial reporting policies from those reflected in the Annual Report on Form 10-K for the year ended December 31, 2017 . For further information with regard to the Company’s Significant Accounting Policies, please refer to Note 1, "Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies," to the Company’s Consolidated Financial Statements included in the 2017 Annual Report on Form 10-K.

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies (Tables)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Error Correction and Prior Period Adjustments	The following table summarizes the effects of the error on the interim and annual prior-period financial statements: Nine Months Ended, Year Ended, September 30, 2017 December 31, 2017 (in millions) As Previously Reported Adjustment As Revised As Previously Reported Adjustment As Revised CASH FLOWS FROM OPERATING ACTIVITIES: Net cash (used in) provided by operating activities from continuing operations $ (11.7 ) $ 2.6 $ (9.1 ) $ (5.4 ) $ 4.4 $ (1.0 ) Effect on currency exchange rate changes on cash and cash equivalents 4.0 (2.6 ) 1.4 6.4 (4.4 ) 2.0

Inventories, net (Tables)

Inventories, net (Tables)	9 Months Ended
	Sep. 30, 2018
Inventory Disclosure [Abstract]
Schedule of Inventories	The following is a summary of inventories presented on GCP's accompanying unaudited Consolidated Balance Sheets at September 30, 2018 and December 31, 2017: (In millions) September 30, December 31, Raw materials $ 47.3 $ 41.9 In process 4.4 3.5 Finished products and other 64.2 60.9 Total inventories, net $ 115.9 $ 106.3

Debt and Other Borrowings (Tabl

Debt and Other Borrowings (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Components of Debt	Components of Debt The following is a summary of obligations under senior notes and other borrowings at September 30, 2018 and December 31, 2017: (In millions) September 30, December 31, 5.5% Senior Notes due in 2026, net of unamortized debt issuance costs of $4.5 million at September 30, 2018 $ 345.5 $ — 9.5% Senior Notes due in 2023, net of unamortized debt issuance costs of $6.4 million at December 31, 2017 — 518.6 Revolving credit facility due 2023 (1) — — Other borrowings (2) 12.1 25.7 Total debt 357.6 544.3 Less debt payable within one year 10.9 24.0 Debt payable after one year $ 346.7 $ 520.3 Weighted average interest rates on total debt obligations 5.7 % 9.4 % __________________________ (1) Represents borrowings under the Revolving Credit Facility with an aggregate available principal amount of $350.0 million and $250.0 million , respectively, as of September 30, 2018 and December 31, 2017. (2) Represents borrowings under various lines of credit and other borrowings, primarily by non-U.S. subsidiaries.
Principal Maturities of Debt Outstanding	The principal maturities of debt obligations outstanding, net of debt issuance costs, were as follows at September 30, 2018 : (In millions) Year ending December 31, Amount 2018 $ 10.4 2019 1.2 2020 0.5 2021 — 2022 — Thereafter 345.5 Total debt $ 357.6
Carrying Amounts and Fair Values of Debt Instruments	At September 30, 2018 , the carrying amounts and fair values of GCP's debt were as follows: September 30, 2018 December 31, 2017 (In millions) Carrying Amount Fair Value Carrying Amount Fair Value 9.5% Senior Notes due in 2023 $ — $ — $ 518.6 $ 584.5 5.5% Senior Notes due in 2026 345.5 344.0 — — Other borrowings 12.1 12.1 25.7 25.7 Total debt $ 357.6 $ 356.1 $ 544.3 $ 610.2

Pension Plans and Other Postr_2

Pension Plans and Other Postretirement Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2018
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Net Funded Status of Over-Funded, Underfunded, and Unfunded Pension Plans	The following table presents the funded status of GCP's overfunded, underfunded and unfunded defined pension plans related to continuing operations: (In millions) September 30, December 31, Overfunded defined benefit pension plans $ 26.1 $ 26.4 Underfunded defined benefit pension plans (26.4 ) (26.6 ) Unfunded defined benefit pension plans (30.2 ) (30.5 ) Total underfunded and unfunded defined benefit pension plans (56.6 ) (57.1 ) Pension liabilities included in other current liabilities (2.0 ) (1.0 ) Net funded status $ (32.5 ) $ (31.7 )
Components of Net Periodic Benefit Cost (Income)	Components of Net Periodic Benefit Cost The components of GCP's net periodic benefit cost for the three and nine months ended September 30, 2018 and 2017 are as follows: Three Months Ended September 30, 2018 2017 Pension Pension (In millions) U.S. Non-U.S. U.S. Non-U.S. Service cost $ 2.0 $ 0.8 $ 1.6 $ 0.8 Interest cost 1.4 1.4 1.3 1.4 Expected return on plan assets (1.9 ) (1.7 ) (1.4 ) (1.6 ) Mark-to-market adjustment — — 1.2 1.7 Gain on curtailments, settlements, and terminations — — (2.8 ) (14.3 ) Net periodic benefit cost (income) $ 1.5 $ 0.5 $ (0.1 ) $ (12.0 ) Less: Discontinued operations net periodic benefit income — — (2.1 ) (14.4 ) Net periodic benefit cost from continuing operations $ 1.5 $ 0.5 $ 2.0 $ 2.4 Nine Months Ended September 30, 2018 2017 Pension Pension (In millions) U.S. Non-U.S. U.S. Non-U.S. Service cost $ 6.0 $ 2.4 $ 5.3 $ 3.0 Interest cost 4.2 4.2 4.2 4.3 Expected return on plan assets (5.7 ) (5.3 ) (4.2 ) (5.1 ) Mark-to-market adjustment — (0.3 ) 1.2 1.6 Gain on curtailments, settlements, and terminations — (0.1 ) (8.4 ) (14.3 ) Net periodic benefit cost (income) $ 4.5 $ 0.9 $ (1.9 ) $ (10.5 ) Less: Discontinued operations net periodic benefit income — — (2.6 ) (13.9 ) Net periodic benefit cost from continuing operations $ 4.5 $ 0.9 $ 0.7 $ 3.4

Other Balance Sheet Accounts (T

Other Balance Sheet Accounts (Tables)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Other Current Assets	The following is a summary of other current assets at September 30, 2018 and December 31, 2017: (In millions) September 30, December 31, Other Current Assets: Non-trade receivables $ 26.4 $ 28.4 Prepaid expenses and other current assets 9.6 13.8 Income taxes receivable 11.2 6.0 Marketable securities — 0.4 Total other current assets $ 47.2 $ 48.6
Schedule of Other Current Liabilities	The following is a summary of other current liabilities at September 30, 2018 and December 31, 2017: (In millions) September 30, December 31, Other Current Liabilities: Accrued customer volume rebates $ 33.2 $ 31.5 Accrued compensation (1) 16.7 27.1 Income taxes payable (2) 25.7 115.1 Accrued interest 9.4 20.8 Pension liabilities 2.0 1.0 Restructuring liability 13.3 12.8 Other accrued liabilities (3) 56.5 107.9 Total other current liabilities $ 156.8 $ 316.2 ________________________________ (1) Accrued compensation presented in the table above includes salaries and wages, as well as estimated current amounts due under the annual and long-term employee incentive programs. (2) The change in income taxes payable between September 30, 2018 and December 31, 2017 is related primarily to the payment of $105.0 million related to the Company's provisional 2017 domestic income tax liability which was impacted by the sale of Darex and the 2017 Tax Act. (3) Other accrued liabilities presented in the table above as of September 30, 2018 and December 31, 2017 include $13.1 million and $55.1 million , respectively, representing the current portion of the liability related to the delayed closings associated with the Company's divestiture of Darex, as discussed in Note 15, "Discontinued Operations."

Restructuring and Repositioni_2

Restructuring and Repositioning Expenses (Tables)	9 Months Ended
	Sep. 30, 2018
Restructuring and Related Activities [Abstract]
Schedule of Restructuring Expenses	The following table summarizes restructuring costs and asset impairment charges related to the 2017 and 2018 Plans and other plans incurred during each period: Three Months Ended September 30, Nine Months Ended September 30, (In millions) 2018 2017 2018 2017 Severance and other employee costs $ 10.0 $ 2.1 9.3 $ 19.0 Facility exit costs 0.2 — 0.2 0.1 Asset impairments 4.1 0.4 4.5 0.8 Total restructuring expenses and asset impairments $ 14.3 $ 2.5 $ 14.0 $ 19.9 Less: restructuring expenses and asset impairments reflected in discontinued operations — 0.4 0.8 6.9 Total restructuring expenses and asset impairments from continuing operations $ 14.3 $ 2.1 $ 13.2 $ 13.0 GCP incurred restructuring costs and asset impairment charges related to its two operating segments and Corporate as follows: Three Months Ended September 30, Nine Months Ended September 30, (In millions) 2018 2017 2018 2017 SCC $ 11.9 $ 0.7 $ 10.9 $ 6.2 SBM 2.3 (0.3 ) 1.9 4.1 Corporate 0.1 1.7 0.4 2.7 Total restructuring expenses and asset impairments from continuing operations $ 14.3 $ 2.1 $ 13.2 $ 13.0 Restructuring expenses and asset impairments reflected in discontinued operations — 0.4 0.8 6.9 Total restructuring expenses and asset impairments $ 14.3 $ 2.5 $ 14.0 $ 19.9
Schedule of Restructuring Liability	The following table summarizes the Company’s restructuring liability activity: 2018 Plan 2017 Plan (In millions) Severance and other employee costs Facility exit costs Severance and other employee costs Facility exit costs Other plans Total Balance, December 31, 2017 $ — $ — $ 11.6 $ 0.1 $ 1.1 $ 12.8 Expense (1) 10.3 — (1.7 ) 0.2 0.7 9.5 Payments (1.2 ) — (6.1 ) (0.1 ) (1.1 ) (8.5 ) Impact of foreign currency and other — — (0.3 ) — (0.2 ) (0.5 ) Balance, September 30, 2018 $ 9.1 $ — $ 3.5 $ 0.2 $ 0.5 $ 13.3 ________________________________ (1) Asset impairment charges of $4.5 million for the nine months ended September 30, 2018 related to the 2017 and 2018 Plans are recorded as a reduction to "Properties and equipment, net" in the accompanying unaudited Consolidated Balance Sheets. These expenses are not recorded to the restructuring liability and therefore, are not included in the table above.
Schedule of Repositioning Expenses	Separation-related repositioning expenses incurred for the three and nine months ended September 30, 2017 were as follows: Three Months Ended September 30, 2017 Nine Months Ended September 30, 2017 (In millions) Professional fees $ — $ 3.4 Software and IT implementation fees — 0.9 Employee-related costs — 1.0 Total $ — $ 5.3

Other Comprehensive (Loss) In_2

Other Comprehensive (Loss) Income (Tables)	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Schedule of Pre-tax, Tax, and After-tax Components of Other Comprehensive Income (Loss)	The following tables present the pre-tax, tax and after-tax components of GCP's other comprehensive (loss) income for the three and nine months ended September 30, 2018 and 2017 : Three Months Ended September 30, 2018 (In millions) Pre-Tax Amount Tax (Expense) After-Tax Amount Defined benefit pension and other postretirement plans $ 0.3 $ (0.1 ) $ 0.2 Currency translation adjustments (1) (9.1 ) — (9.1 ) Other comprehensive loss attributable to GCP shareholders $ (8.8 ) $ (0.1 ) $ (8.9 ) Nine Months Ended September 30, 2018 (In millions) Pre-Tax Amount Tax Benefit After-Tax Amount Defined benefit pension and other postretirement plans $ (0.5 ) $ 0.1 $ (0.4 ) Currency translation adjustments (1) (27.3 ) — (27.3 ) Gain from hedging activities 0.1 — 0.1 Other comprehensive loss attributable to GCP shareholders $ (27.7 ) $ 0.1 $ (27.6 ) Three Months Ended September 30, 2017 (In millions) Pre-Tax Amount Tax Expense After-Tax Amount Defined benefit pension and other postretirement plans $ (0.3 ) $ — $ (0.3 ) Currency translation adjustments (1) 46.2 — 46.2 Gain from hedging activities 0.8 (0.3 ) 0.5 Other comprehensive income attributable to GCP shareholders $ 46.7 $ (0.3 ) $ 46.4 Nine Months Ended September 30, 2017 (In millions) Pre-Tax Amount Tax Benefit After-Tax Amount Defined benefit pension and other postretirement plans $ (0.3 ) $ — $ (0.3 ) Currency translation adjustments (1) 63.0 — 63.0 Loss from hedging activities (0.1 ) — (0.1 ) Other comprehensive income attributable to GCP shareholders $ 62.6 $ — $ 62.6 (1) Currency translation adjustments did not have a corresponding tax effect.
Schedule of Changes of Accumulated Other Comprehensive Income (Loss), Net of Tax	The following tables present the changes in accumulated other comprehensive loss, net of tax, for the nine months ended September 30, 2018 and 2017 : (In millions) Defined Benefit Pension and Other Postretirement Plans Currency Translation Adjustments Hedging Activities Total Balance, December 31, 2017 $ 0.4 $ (86.0 ) $ (0.1 ) $ (85.7 ) Other comprehensive (loss) income before reclassifications (0.4 ) (27.3 ) 0.2 (27.5 ) Amounts reclassified from accumulated other comprehensive (loss) income — — (0.1 ) (0.1 ) Current-period other comprehensive (loss) income (0.4 ) (27.3 ) 0.1 (27.6 ) Balance, September 30, 2018 $ — $ (113.3 ) $ — $ (113.3 ) (In millions) Defined Benefit Pension and Other Postretirement Plans Currency Translation Adjustments Hedging Activities Total Balance, December 31, 2016 $ 0.1 $ (147.7 ) $ — $ (147.6 ) Other comprehensive (loss) income before reclassifications (0.3 ) 63.0 (0.7 ) 62.0 Amounts reclassified from accumulated other comprehensive (loss) income — — 0.6 0.6 Net current-period other comprehensive (loss) income (0.3 ) 63.0 (0.1 ) 62.6 Balance, September 30, 2017 $ (0.2 ) $ (84.7 ) $ (0.1 ) $ (85.0 )

Stock Incentive Plans (Tables)

Stock Incentive Plans (Tables)	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Assumptions for Estimating the Fair Value of Stock Options	The following summarizes GCP's assumptions for estimating the fair value of stock options granted during 2018 and 2017 : Nine Months Ended September 30, Assumptions used to calculate expense for stock options: 2018 2017 Risk-free interest rate 2.68-2.90% 1.83 - 2.10% Average life of options (years) 5.5-6.5 5.5 - 6.5 Volatility 27.91-30.65% 31.42 - 31.96% Dividend yield — — Weighted average fair value per stock option $10.63 $9.16
Summary of Stock Option Activity	The following table sets forth information relating to stock options denominated in GCP stock during the nine months ended September 30, 2018 : Stock Option Activity Number Of Weighted Weighted Aggregated Outstanding, December 31, 2017 1,636 $ 18.94 3.78 $ 21,597 Options exercised 314 16.76 Options forfeited/expired/canceled 25 25.41 Options granted 241 31.31 Outstanding, September 30, 2018 1,538 $ 21.21 3.99 $ 9,262 Exercisable, September 30, 2018 968 $ 18.87 2.79 $ 7,339 Vested and expected to vest, September 30, 2018 1,520 $ 21.15 3.96 $ 9,222
Summary of Restricted Stock Units Award Activity	GCP’s RSU activity for the nine months ended September 30, 2018 is presented below: RSU Activity Number Of Weighted Outstanding, December 31, 2017 406 $ 19.15 RSUs settled 158 18.36 RSUs forfeited 10 27.97 RSUs granted 129 29.28 RSUs outstanding, September 30, 2018 367 $ 22.83
Schedule of Assumptions for Estimating the Fair Value of PBUs	The following summarizes the assumptions used in the Monte Carlo simulations for estimating the grant date fair values of PBUs granted during the nine months ended September 30, 2018 and 2017: Nine Months Ended September 30, Assumptions used to calculate expense for PBUs: 2018 2017 Expected Term (Remaining Performance Period) 2.86 2.84 Expected volatility 28.56% 28.00% Risk-free interest rate 2.38% 1.41% Expected dividends — — Correlation coefficient 38.98% 46.83% Average correlation coefficient of constituents 39.96% 42.33%

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Reconciliation of the Numerators and Denominators Used in Calculating Basic and Diluted Earnings Per Share	The following table shows a reconciliation of the numerators and denominators used in calculating basic and diluted earnings (loss) per share: Three Months Ended September 30, Nine Months Ended September 30, (In millions, except per share amounts) 2018 2017 2018 2017 Numerators Income (loss) from continuing operations attributable to GCP shareholders $ 7.2 $ (18.1 ) $ (35.8 ) $ (41.8 ) Income from discontinued operations, net of income taxes 18.2 677.3 26.7 679.4 Net income (loss) attributable to GCP shareholders $ 25.4 $ 659.2 $ (9.1 ) $ 637.6 Denominators Weighted average common shares—basic calculation 72.2 71.6 72.1 71.2 Dilutive effect of employee stock awards (1) 0.5 — — — Weighted average common shares—diluted calculation 72.7 71.6 72.1 71.2 Basic earnings (loss) per share Income (loss) from continuing operations attributable to GCP shareholders $ 0.10 $ (0.25 ) $ (0.50 ) $ (0.59 ) Income from discontinued operations, net of income taxes $ 0.25 $ 9.46 $ 0.37 $ 9.54 Net income (loss) attributable to GCP shareholders (2) $ 0.35 $ 9.21 $ (0.13 ) $ 8.96 Diluted earnings (loss) per share Income (loss) from continuing operations attributable to GCP shareholders $ 0.10 $ (0.25 ) $ (0.50 ) $ (0.59 ) Income from discontinued operations, net of income taxes $ 0.25 $ 9.46 $ 0.37 $ 9.54 Net income (loss) attributable to GCP shareholders (2) $ 0.35 $ 9.21 $ (0.13 ) $ 8.96 ________________________________ (1) Dilutive effect not applicable to periods in which GCP generated a loss from continuing operations. (2) Amounts may not sum due to rounding.
Schedule of Dilutive Effect of Options and RSUs	The following table summarizes options and RSUs excluded from dilutive shares and diluted loss per share shown in the table above: Three Months Ended September 30, Nine Months Ended September 30, (In millions of shares) 2018 2017 2018 2017 Dilutive effect: Options (1) N/A 0.6 0.5 0.7 RSUs (1) N/A 0.4 0.2 0.4 ________________________________ (1) N/A - Dilutive effect is included in computation of diluted earnings per share under the treasury stock method for periods in which GCP generated income from continuing operations.

Operating Segment and Geograp_2

Operating Segment and Geographic Information (Tables)	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Schedule of Operating Segment Data	The following table presents information related to GCP's operating segments: Three Months Ended September 30, Nine Months Ended September 30, (In millions) 2018 2017 2018 2017 Net Sales Specialty Construction Chemicals $ 165.4 $ 156.2 $ 487.4 $ 449.1 Specialty Building Materials 130.9 126.2 361.9 345.8 Total net sales $ 296.3 $ 282.4 $ 849.3 $ 794.9 Segment Operating Income Specialty Construction Chemicals segment operating income $ 12.7 $ 15.7 $ 31.2 $ 44.5 Specialty Building Materials segment operating income 34.3 30.1 84.2 80.6 Total segment operating income $ 47.0 $ 45.8 $ 115.4 $ 125.1
Reconciliation of Operating Segment Data to Financial Statements	Total segment operating income for the three and nine months ended September 30, 2018 and 2017 , is reconciled below to " Income (loss) from continuing operations before income taxes " presented in the accompanying unaudited Consolidated Statements of Operations: Three Months Ended September 30, Nine Months Ended September 30, (In millions) 2018 2017 2018 2017 Total segment operating income $ 47.0 $ 45.8 $ 115.4 $ 125.1 Corporate costs (1) (5.3 ) (7.5 ) (22.8 ) (28.9 ) Certain pension costs (2.0 ) (2.1 ) (5.8 ) (7.0 ) Loss on sale of product line — — — (2.1 ) Currency and other financial losses in Venezuela — (36.7 ) — (39.1 ) Litigation settlement — (4.0 ) — $ (4.0 ) Repositioning expenses (3.7 ) (1.1 ) (5.8 ) $ (6.8 ) Restructuring expenses and asset impairments (14.3 ) (2.1 ) (13.2 ) $ (13.0 ) Pension MTM adjustment and other related costs, net — (3.0 ) (0.9 ) $ (2.9 ) Gain on termination and curtailment of pension and other postretirement plans — 0.8 0.1 $ 5.9 Third-party and other acquisition-related costs (0.5 ) (2.0 ) (2.1 ) $ (5.0 ) Amortization of acquired inventory fair value adjustment — (0.2 ) (0.2 ) $ (2.9 ) Tax indemnification adjustments — — — (2.4 ) Net income attributable to noncontrolling interests 0.1 0.1 0.3 0.2 Other financing costs — (6.0 ) — (6.0 ) Interest expense, net (2) (5.3 ) (14.5 ) (83.6 ) (49.0 ) Currency losses in Argentina (1.1 ) — (1.1 ) — Income (loss) from continuing operations before income taxes $ 14.9 $ (32.5 ) $ (19.7 ) $ (37.9 ) _______________________________ (1) Management allocates corporate costs to each segment to the extent such costs are directly attributable to the segments. Corporate costs include approximately $5.4 million of allocated costs during the nine months ended September 30, 2017 that were previously reported within the Darex operating segment since such costs did not meet the criteria to be reclassified to discontinued operations. Beginning with the third quarter of 2017, the Company began allocating these costs to its remaining operating segments. (2) Interest expense, net includes a loss of $59.8 million as a result of debt refinancing transaction completed on April 10, 2018. Please refer to Note 4, "Debt and Other Borrowings" for further information on the transaction.
Schedule of Geographic Area Data	The table below presents information related to the geographic areas in which GCP operates. Sales are attributed to geographic areas based on customer location. Three Months Ended September 30, Nine Months Ended September 30, (In millions) 2018 2017 2018 2017 Net Sales United States $ 144.4 $ 132.5 $ 402.4 $ 374.2 Canada and Puerto Rico 9.7 9.0 24.0 21.8 Total North America 154.1 141.5 426.4 396.0 Europe Middle East Africa 61.7 67.0 189.2 178.9 Asia Pacific 63.9 58.0 181.6 168.4 Latin America 16.6 15.9 52.1 51.6 Total $ 296.3 $ 282.4 $ 849.3 $ 794.9

Discontinued Operations (Tables

Discontinued Operations (Tables)	9 Months Ended
	Sep. 30, 2018
Discontinued Operations and Disposal Groups [Abstract]
Reconciliation of Gain on Disposal	The following table includes a reconciliation of the gain on the sale of the Darex business related to delayed close entities recorded during the three and nine months ended September 30, 2018 and September 30, 2017: Three Months Ended September 30, Nine Months Ended September 30, (In millions) 2018 2017 2018 2017 Net proceeds included in gain $ 30.4 $ 1,000.2 $ 55.4 $ 1,000.2 Less: Transaction costs — 15.9 — 15.9 Less: Net assets derecognized 5.4 100.6 11.9 100.6 Gain recognized before income taxes 25.0 883.7 43.5 883.7 Less: Tax effect of gain recognized 6.2 200.0 14.4 200.0 Gain recognized after income taxes $ 18.8 $ 683.7 $ 29.1 $ 683.7
Financial Results and Other Effects Related to Discontinued Operations	The components of "Income from discontinued operations, net of income taxes" in the accompanying unaudited Consolidated Statements of Operations are comprised of the following: Three Months Ended September 30, Nine Months Ended September 30, (In millions) 2018 2017 2018 2017 Net sales $ 1.7 $ 9.1 $ 13.3 $ 156.9 Cost of goods sold 1.2 6.0 13.9 104.6 Gross profit 0.5 3.1 (0.6 ) 52.3 Selling, general and administrative expenses 1.3 6.6 4.6 40.1 Research and development expenses — 0.1 — 2.3 Restructuring and asset impairments — 0.4 0.8 6.9 Gain on sale of business (25.0 ) (883.7 ) (43.5 ) (883.7 ) Other (income) expenses, net (0.1 ) 2.4 (3.2 ) 7.5 Total income (23.8 ) (874.2 ) (41.3 ) (826.9 ) Income from discontinued operations before income taxes 24.3 877.3 40.7 879.2 Provision for income taxes (6.1 ) (200.0 ) (14.0 ) (199.7 ) Less: Net income attributable to noncontrolling interests — — — (0.1 ) Income from discontinued operations, net of income taxes $ 18.2 $ 677.3 $ 26.7 $ 679.4 The carrying amounts of the major classes of assets and liabilities of Darex classified as held for sale in the accompanying unaudited Consolidated Balance Sheets as of September 30, 2018 and December 31, 2017 consist of the following: (In millions) September 30, 2018 December 31, 2017 Trade accounts receivable $ 1.7 $ 8.4 Inventories 1.4 10.6 Other current assets — 0.7 Current assets held for sale $ 3.1 $ 19.7 Properties and equipment, net 0.4 2.2 Other assets 0.5 0.6 Non-current assets held for sale $ 0.9 $ 2.8 Accounts payable 1.1 6.4 Other current liabilities 0.1 1.4 Current liabilities held for sale $ 1.2 $ 7.8 Underfunded and unfunded defined benefit pension plans 0.3 0.3 Non-current liabilities held for sale $ 0.3 $ 0.3

Acquisitions and Dispositions (

Acquisitions and Dispositions (Tables)	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Schedule of Purchase Price Allocation	The following table presents the aggregate purchase price allocation as of September 30, 2018: (In millions) Net Assets Acquired Accounts receivable $ 2.2 Other current assets 0.2 Properties and equipment 0.1 Goodwill 14.0 Intangible assets 15.5 Accounts payable (0.2 ) Net assets acquired $ 31.8 The following table summarizes the updated allocation of the purchase price as of September 30, 2018: (In millions) Net Assets Acquired Accounts receivable (approximates contractual value) $ 1.3 Inventories 0.6 Prepaid expenses and other current assets 0.1 Property, plant and equipment 0.1 Intangible assets 10.7 Goodwill 19.9 Accounts payable (1.0 ) Accrued liabilities (0.1 ) Deferred tax liabilities (1.9 ) Net assets acquired $ 29.7

Basis of Presentation and Sum_4

Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies - Narrative (Details) $ in Millions	Apr. 10, 2018USD ($)	Jan. 01, 2018USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)segment	Dec. 31, 2017USD ($)	Jul. 03, 2017USD ($)	Jan. 27, 2016
Class of Stock [Line Items]
Number of operating segments | segment					2
Loss in Venezuela, before taxes				$ 36.7
Loss in Venezuela, net of taxes				23.8
Trade accounts receivable			$ 213.1		$ 213.1	$ 217.1
Accounts receivable related to contracts with customers, lease rental income			$ 5		$ 5	5.6
Payment for debt extinguishment	$ 191
Senior Notes
Class of Stock [Line Items]
Stated interest rate								9.50%
Senior Notes | 9.5% Senior Notes due in 2023
Class of Stock [Line Items]
Stated interest rate			9.50%		9.50%			9.50%
Accounting Standards Update 2016-15
Class of Stock [Line Items]
Payment for debt extinguishment		$ 53.3
ARGENTINA | Subsidiaries
Class of Stock [Line Items]
Loss on remeasurement of subsidiary net monetary assets			$ 1.1
Loss in Venezuela
Class of Stock [Line Items]
Remeasurement and impairment loss from deconsolidation				$ 33.4
Disposed of by Sale | Darex
Class of Stock [Line Items]
Consideration received							$ 1,060
Reduction in deferred consideration					$ 55.1
Disposed of by Sale | Darex | Other current liabilities
Class of Stock [Line Items]
Disposal group, deferred consideration			13.1		13.1	55.1
Disposed of by Sale | Darex | Other Liabilities
Class of Stock [Line Items]
Disposal group, deferred consideration			$ 0.5		$ 0.5	$ 13.6

Basis of Presentation and Sum_5

Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies - Schedule of Error Correction and Prior Period Adjustments (Details) - USD ($) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net cash (used in) provided by operating activities from continuing operations	$ 29.6	$ (9.1)
Effect on currency exchange rate changes on cash and cash equivalents	$ (2.6)	1.4
Correction Of Currency Exchange Rate Error
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net cash (used in) provided by operating activities from continuing operations		(9.1)	$ (1)
Effect on currency exchange rate changes on cash and cash equivalents		1.4	2
As Previously Reported | Correction Of Currency Exchange Rate Error
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net cash (used in) provided by operating activities from continuing operations		(11.7)	(5.4)
Effect on currency exchange rate changes on cash and cash equivalents		4	6.4
Adjustment | Correction Of Currency Exchange Rate Error
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net cash (used in) provided by operating activities from continuing operations		2.6	4.4
Effect on currency exchange rate changes on cash and cash equivalents		$ (2.6)	$ (4.4)

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2018USD ($)
Revenue from Contract with Customer [Abstract]
Revenue recognized	$ 8.6	$ 25
Sales returns, period of returns allowed		6 months
Revenue, remaining performance obligation	$ 4.5	$ 4.5

Inventories, net - Schedule of

Inventories, net - Schedule of Inventory (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Raw materials	$ 47.3	$ 41.9
In process	4.4	3.5
Finished products and other	64.2	60.9
Total inventories, net	$ 115.9	$ 106.3

Inventories, net - Narrative (D

Inventories, net - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Inventory [Line Items]
Finished products and other	$ 64.2	$ 60.9
Finished Products Purchased
Inventory [Line Items]
Finished products and other	$ 14.2	$ 11.1

Debt and Other Borrowings - Com

Debt and Other Borrowings - Components of Debt (Details) - USD ($)	Sep. 30, 2018	Apr. 10, 2018	Dec. 31, 2017	Jan. 27, 2016
Debt Instrument [Line Items]
Long term debt	$ 357,600,000		$ 544,300,000
Debt payable within one year	10,900,000		24,000,000
Debt payable after one year	$ 346,700,000		$ 520,300,000
Weighted average interest rates	5.70%		9.40%
Senior Notes | 5.5% Senior Notes due in 2026, net of unamortized debt issuance costs of $4.5 million at September 30, 2018
Debt Instrument [Line Items]
Long term debt	$ 345,500,000	$ 346,900,000	$ 0
Senior Notes | 9.5% Senior Notes due in 2023, net of unamortized debt issuance costs of $6.4 million at December 31, 2017
Debt Instrument [Line Items]
Long term debt	0		518,600,000
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Long term debt	0		0
Aggregate available principal amount	350,000,000	$ 350,000,000	250,000,000	$ 250,000,000
Other Borrowings
Debt Instrument [Line Items]
Long term debt	$ 12,100,000		$ 25,700,000

Debt and Other Borrowings - C_2

Debt and Other Borrowings - Components of Debt (Additional Information) (Details) - USD ($)	Sep. 30, 2018	Apr. 10, 2018	Dec. 31, 2017	Jan. 27, 2016
Senior Notes
Debt Instrument [Line Items]
Stated interest rate				9.50%
Unamortized debt issuance cost			$ 6,400,000
5.5% Senior Notes due in 2026, net of unamortized debt issuance costs of $4.5 million at September 30, 2018 | Senior Notes
Debt Instrument [Line Items]
Stated interest rate	5.50%	5.50%
Unamortized debt issuance cost	$ 4,500,000
9.5% Senior Notes due in 2023, net of unamortized debt issuance costs of $6.4 million at December 31, 2017 | Senior Notes
Debt Instrument [Line Items]
Stated interest rate	9.50%			9.50%
Revolving Credit Facility | Line of Credit [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 350,000,000	$ 350,000,000	$ 250,000,000	$ 250,000,000

Debt and Other Borrowings - Pri

Debt and Other Borrowings - Principal Maturities of Debt Outstanding (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
2,018	$ 10.4
2,019	1.2
2,020	0.5
2,021	0
2,022	0
Thereafter	345.5
Total debt	$ 357.6	$ 544.3

Debt and Other Borrowings - Nar

Debt and Other Borrowings - Narrative (Details) - USD ($)	Oct. 15, 2018	Apr. 10, 2018	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Feb. 03, 2016	Jan. 27, 2016
Debt Instrument [Line Items]
Payment for debt extinguishment		$ 191,000,000
Loss on debt financing before write off of debt issuance costs			$ 59,400,000	$ 59,400,000
Loss on debt refinancing		59,800,000		59,800,000	$ 0
Long term debt			$ 357,600,000	357,600,000		$ 544,300,000
Line of credit, aggregate payments				$ 66,400,000	$ 416,600,000
Credit Agreement | United States
Debt Instrument [Line Items]
Pledged equity to credit facilities, percentage							100.00%
Credit Agreement | United Kingdom
Debt Instrument [Line Items]
Pledged equity to credit facilities, percentage							65.00%
Credit Agreement | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity							$ 525,000,000
Senior Notes
Debt Instrument [Line Items]
Stated interest rate								9.50%
Aggregate principal amount								$ 525,000,000
Unamortized debt issuance cost						6,400,000
Senior Notes | Debt Instrument, Redemption, Period One | Treasury Bond Yield
Debt Instrument [Line Items]
Spread over variable rate				0.50%
Senior Notes | 9.5% Senior Notes due in 2023
Debt Instrument [Line Items]
Stated interest rate			9.50%	9.50%				9.50%
Aggregate principal amount								$ 525,000,000
Extinguishment of debt		587,900,000
Redemption premium		53,300,000
Payment of accrued interest		9,600,000
Write off of debt issuance costs		$ 6,100,000		$ 6,100,000
Long term debt			$ 0	$ 0		518,600,000
Senior Notes | 5.5% Senior Notes due in 2026
Debt Instrument [Line Items]
Stated interest rate		5.50%	5.50%	5.50%
Aggregate principal amount		$ 350,000,000
Loan origination fees		3,100,000
Long term debt		$ 346,900,000	$ 345,500,000	$ 345,500,000		0
Issue price percentage		99.10%
Debt discount		$ 3,100,000
Debt discount, percentage of par value		0.90%
Additional debt issuance costs				1,600,000
Redemption price percentage		100.00%
Covenant compliance, minimum discharge of final judgements		$ 50,000,000
Gross debt issuance costs		$ 4,700,000
Unamortized debt issuance cost			4,500,000	4,500,000
Senior Notes | 5.5% Senior Notes due in 2026 | Subsequent Event
Debt Instrument [Line Items]
Interest payment	$ 9,900,000
Senior Notes | 5.5% Senior Notes due in 2026 | At Any Time And From Time To Time Prior To April 15, 2021
Debt Instrument [Line Items]
Redemption price percentage		40.00%
Senior Notes | 5.5% Senior Notes due in 2026 | Any Time Prior To April 15, 2021
Debt Instrument [Line Items]
Redemption price percentage		105.50%
Senior Notes | 5.5% Senior Notes due in 2026 | After April 15, 2021
Debt Instrument [Line Items]
Redemption price percentage		102.80%
Senior Notes | 5.5% Senior Notes due in 2026 | After April 15, 2022
Debt Instrument [Line Items]
Redemption price percentage		101.40%
Senior Notes | 5.5% Senior Notes due in 2026 | After April 15, 2023
Debt Instrument [Line Items]
Redemption price percentage		100.00%
Senior Notes | 5.5% Senior Notes due in 2026 | Upon Occurrence of Change In Control
Debt Instrument [Line Items]
Redemption price percentage		101.00%
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 350,000,000	350,000,000	350,000,000		250,000,000		$ 250,000,000
Outstanding draw on revolving loans		50,000,000
Line of credit, unamortized debt issuance costs			4,300,000	4,300,000		3,200,000
Long term debt			0	0		$ 0
Additional debt issuance costs				2,200,000
Line of Credit | Revolving Credit Facility | Syndicate of Financial Institutions
Debt Instrument [Line Items]
Write off of debt issuance costs		$ 400,000		400,000
Term Loan | Credit Agreement | Line of Credit
Debt Instrument [Line Items]
Aggregate principal amount							275,000,000
Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Outstanding draw on revolving loans			0	0
Payment of accrued interest			$ 0	$ 200,000
Line of credit, weighted average interest rate			0.00%	3.40%
Line of credit, aggregate payments				$ 50,000,000
Outstanding letters of credit			$ 5,700,000	5,700,000
Current borrowing capacity			$ 344,300,000	$ 344,300,000
Revolving Credit Facility | Credit Agreement | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity							$ 250,000,000
Revolving Credit Facility | Credit Agreement | Line of Credit | Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate				0.50%
Revolving Credit Facility | Credit Agreement | Line of Credit | Base Rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate				1.00%
Revolving Credit Facility | Credit Agreement | Line of Credit | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate				1.50%
Revolving Credit Facility | Credit Agreement | Line of Credit | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate				2.00%

Debt and Other Borrowings - Car

Debt and Other Borrowings - Carrying Amounts and Fair Values of Debt Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2018	Apr. 10, 2018	Dec. 31, 2017	Jan. 27, 2016
Senior Notes
Debt Instrument [Line Items]
Stated interest rate				9.50%
9.5% Senior Notes due in 2023 | Senior Notes
Debt Instrument [Line Items]
Stated interest rate	9.50%			9.50%
5.5% Senior Notes due in 2026 | Senior Notes
Debt Instrument [Line Items]
Stated interest rate	5.50%	5.50%
Carrying Amount
Debt Instrument [Line Items]
Long-term debt, fair value	$ 357.6		$ 544.3
Carrying Amount | Other Borrowings
Debt Instrument [Line Items]
Long-term debt, fair value	12.1		25.7
Carrying Amount | 9.5% Senior Notes due in 2023 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, fair value	0		518.6
Carrying Amount | 5.5% Senior Notes due in 2026 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, fair value	345.5		0
Fair Value
Debt Instrument [Line Items]
Long-term debt, fair value	356.1		610.2
Fair Value | Other Borrowings
Debt Instrument [Line Items]
Long-term debt, fair value	12.1		25.7
Fair Value | 9.5% Senior Notes due in 2023 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, fair value	0		584.5
Fair Value | 5.5% Senior Notes due in 2026 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, fair value	$ 344		$ 0

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	Apr. 10, 2018	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Income tax expense (benefit)		$ 7.6		$ (14.5)	$ 15.8	$ 3.7
Effective tax rate		51.00%		(44.60%)	80.20%	9.80%
Change in valuation allowance		$ 3.6			$ 4.7	$ 13.9
Foreign income tax rate differential		0.2			0.9
Permanent book to tax differences		0.7			1.8	0.5
Tax on undistributed foreign earnings				$ 2.9		3.6
Tax rate differential due to Tax Cuts and Jobs Act of 2017					12.5
Tax Cuts and Jobs Act of 2017, provisional income tax expense			$ 12.5				$ 81.7
Tax Cuts and Jobs Act of 2017, transition tax for accumulated foreign earnings, income tax expense							70.5
Tax Cuts and Jobs Act of 2017, revaluation of net deferred tax assets							$ 11.2
Tax Cuts and Jobs Act of 2017, provisional income tax expense, capital gains			17.4
Tax Cuts and Jobs Act of 2017, provisional income tax expense, deferred tax			0.3
Tax Cuts and Jobs Act of 2017, provisional income tax benefit, transition toll tax			$ 5.2
Foreign operating loss carryforwards						13.8
Loss on debt refinancing	$ 59.8				59.8	0
Loss on debt refinancing, income tax benefit	$ 14.8
Canada Revenue Agency
Operating Loss Carryforwards [Line Items]
Expected refund as a result of tax settlement				1.5		1.5
Charge to deferred tax assets related to settlement						1.6
Valuation Allowance, Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Foreign operating loss carryforwards						4.3
Net Operating Loss Carryforwards | BRAZIL
Operating Loss Carryforwards [Line Items]
Foreign operating loss carryforwards						9.1
Net Operating Loss Carryforwards | TURKEY
Operating Loss Carryforwards [Line Items]
Foreign operating loss carryforwards						0.4
Discontinued operations | Darex
Operating Loss Carryforwards [Line Items]
Provision for income taxes of discontinued operations		$ 6.1		$ 200	$ 14	$ 199.7

Pension Plans and Other Postr_3

Pension Plans and Other Postretirement Benefit Plans - Net Funded Status of Over-Funded, Underfunded, and Unfunded Pension Plans (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Pension plans and other postretirement benefit plans
Overfunded defined benefit pension plans	$ 26.1	$ 26.4
Underfunded and unfunded defined benefit pension plans	(56.6)	(57.1)
Pension Plans
Pension plans and other postretirement benefit plans
Overfunded defined benefit pension plans	26.1	26.4
Underfunded and unfunded defined benefit pension plans	(56.6)	(57.1)
Pension liabilities included in other current liabilities	(2)	(1)
Net funded status	(32.5)	(31.7)
Underfunded defined benefit pension plans | Pension Plans
Pension plans and other postretirement benefit plans
Underfunded and unfunded defined benefit pension plans	(26.4)	(26.6)
Unfunded defined benefit pension plans | Pension Plans
Pension plans and other postretirement benefit plans
Underfunded and unfunded defined benefit pension plans	$ (30.2)	$ (30.5)

Pension Plans and Other Postr_4

Pension Plans and Other Postretirement Benefit Plans - Narrative (Details) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Pension plans and other postretirement benefit plans
Curtailment gain	$ 0		$ 17,100,000	$ 100,000	$ 5,800,000
Defined Benefit Plan, Settlements and Curtailments, Benefit Obligation					22,700,000
Mark-to-market gain (loss)	0		(2,900,000)		(2,800,000)
Percentage that the employer contributes of employee contributions under 401(k) plan				100.00%
Maximum percentage of employee compensation match by employer to defined contribution plan				6.00%
Additional maximum percentage of employee compensation match by employer to defined contribution plan				2.00%
Costs related to defined contribution retirement plan	1,000,000		1,100,000	$ 3,500,000	3,600,000
Postretirement Health Care
Pension plans and other postretirement benefit plans
Defined benefit plan, long term liability		$ 2,000,000		1,800,000
Defined benefit plan, AOCI	400,000	600,000		400,000
Defined benefit plan, AOCI tax impact		200,000		100,000
Defined benefit plan expense	100,000	$ 1,200,000		1,300,000
Non-U.S.
Pension plans and other postretirement benefit plans
Curtailment gain				400,000
Defined benefit plan expense	800,000		800,000	2,400,000	3,000,000
Non-U.S. | Pension Plans
Pension plans and other postretirement benefit plans
Employer contributions	$ 400,000		200,000	4,300,000	1,900,000
Non-U.S. | Pension Plans | BRAZIL
Pension plans and other postretirement benefit plans
Employer contributions				$ 2,900,000
Income (Loss) From Discontinued Operations, Net Of Income Taxes
Pension plans and other postretirement benefit plans
Curtailment gain			16,400,000		16,900,000
Mark-to-market gain (loss)			$ 100,000		100,000
Service cost, interest cost, and expected return on plan assets					$ 500,000

Pension Plans and Other Postr_5

Pension Plans and Other Postretirement Benefit Plans - Components of Net Periodic Benefit Cost (Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
United States
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 2	$ 1.6	$ 6	$ 5.3
Interest cost	1.4	1.3	4.2	4.2
Expected return on plan assets	(1.9)	(1.4)	(5.7)	(4.2)
Mark-to-market adjustment	0	1.2	0	1.2
Gain on curtailments, settlements, and terminations	0	(2.8)	0	(8.4)
Net periodic benefit cost (income)	1.5	(0.1)	4.5	(1.9)
Less: Discontinued operations net periodic benefit income	0	(2.1)	0	(2.6)
Net periodic benefit cost from continuing operations	1.5	2	4.5	0.7
Non-U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0.8	0.8	2.4	3
Interest cost	1.4	1.4	4.2	4.3
Expected return on plan assets	(1.7)	(1.6)	(5.3)	(5.1)
Mark-to-market adjustment	0	1.7	(0.3)	1.6
Gain on curtailments, settlements, and terminations	0	(14.3)	(0.1)	(14.3)
Net periodic benefit cost (income)	0.5	(12)	0.9	(10.5)
Less: Discontinued operations net periodic benefit income	0	(14.4)	0	(13.9)
Net periodic benefit cost from continuing operations	$ 0.5	$ 2.4	$ 0.9	$ 3.4

Other Balance Sheet Accounts -

Other Balance Sheet Accounts - Other Current Assets (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Other Current Assets:
Non-trade receivables	$ 26.4	$ 28.4
Prepaid expenses and other current assets	9.6	13.8
Income taxes receivable	11.2	6
Marketable securities	0	0.4
Total other current assets	$ 47.2	$ 48.6

Other Balance Sheet Accounts _2

Other Balance Sheet Accounts - Other Current Liabilities (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Other Current Liabilities:
Accrued customer volume rebates	$ 33.2	$ 31.5
Accrued compensation	16.7	27.1
Income taxes payable	25.7	115.1
Accrued interest	9.4	20.8
Pension liabilities	2	1
Restructuring liability	13.3	12.8
Other accrued liabilities	56.5	107.9
Total other current liabilities	156.8	316.2
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Tax Cuts and Jobs Act of 2017, change in tax rate, provisional income tax expense	105
Other current liabilities | Darex | Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal group, deferred consideration	$ 13.1	$ 55.1

Commitments and Contingent Li_2

Commitments and Contingent Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Amended Credit Agreement | Standby Letter of Credit
Loss Contingencies [Line Items]
Gross financial assurances issued and outstanding	$ 6	$ 10

Restructuring and Repositioni_3

Restructuring and Repositioning Expenses - Narrative (Details)	Aug. 01, 2018USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)segment	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Dec. 31, 2017USD ($)	Jun. 28, 2017USD ($)
Restructuring Cost and Reserve [Line Items]
Number of operating segments | segment					2
Restructuring liability		$ 13,300,000	$ 13,300,000		$ 13,300,000		$ 13,300,000	$ 12,800,000
2018 Restructuring and Repositioning Plan | Severance and other employee costs
Restructuring Cost and Reserve [Line Items]
Restructuring expenses					(1,700,000)
Restructuring and related cost, percent of total cost	70.00%
Total cash payments					6,100,000
Restructuring liability		3,500,000	3,500,000		3,500,000		3,500,000	11,600,000
2018 Restructuring and Repositioning Plan | Minimum
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses	$ 30,000,000
2018 Restructuring and Repositioning Plan | Maximum
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses	35,000,000
2018 Restructuring And Repositioning Plan, Restructuring Activities
Restructuring Cost and Reserve [Line Items]
Restructuring expenses		14,300,000
2018 Restructuring And Repositioning Plan, Restructuring Activities | SCC
Restructuring Cost and Reserve [Line Items]
Restructuring expenses		12,000,000
2018 Restructuring And Repositioning Plan, Restructuring Activities | SBM
Restructuring Cost and Reserve [Line Items]
Restructuring expenses		2,300,000
2018 Restructuring And Repositioning Plan, Restructuring Activities | Severance and other employee costs
Restructuring Cost and Reserve [Line Items]
Restructuring expenses		10,300,000
2018 Restructuring And Repositioning Plan, Restructuring Activities | Asset impairments
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses	4,000,000
Restructuring expenses		4,000,000
2018 Restructuring And Repositioning Plan, Restructuring Activities | Other restructuring costs
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses	3,000,000
2018 Restructuring And Repositioning Plan, Restructuring Activities | Minimum
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses	$ 20,000,000
Number of positions eliminated as a percent of total employees	8.00%
2018 Restructuring And Repositioning Plan, Restructuring Activities | Minimum | SCC
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses	$ 18,000,000
2018 Restructuring And Repositioning Plan, Restructuring Activities | Minimum | SBM
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses	3,000,000
2018 Restructuring And Repositioning Plan, Restructuring Activities | Minimum | Severance and other employee costs
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses	13,000,000
2018 Restructuring And Repositioning Plan, Restructuring Activities | Minimum | Facility exit costs
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses	1,000,000
2018 Restructuring And Repositioning Plan, Restructuring Activities | Maximum
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses	$ 25,000,000
Number of positions eliminated as a percent of total employees	10.00%
2018 Restructuring And Repositioning Plan, Restructuring Activities | Maximum | SCC
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses	$ 21,000,000
2018 Restructuring And Repositioning Plan, Restructuring Activities | Maximum | SBM
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses	4,000,000
2018 Restructuring And Repositioning Plan, Restructuring Activities | Maximum | Severance and other employee costs
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses	16,000,000
2018 Restructuring And Repositioning Plan, Restructuring Activities | Maximum | Facility exit costs
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses	2,000,000
2018 Restructuring And Repositioning Plan, Repositioning Activities
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses	$ 10,000,000
Restructuring expenses		2,600,000	2,600,000
Total cash payments					0
2017 Restructuring and Repositioning Plan
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses									$ 30,000,000
2017 Restructuring and Repositioning Plan | Severance and other employee costs
Restructuring Cost and Reserve [Line Items]
Restructuring expenses					10,300,000
Total cash payments					1,200,000
Restructuring liability		9,100,000	9,100,000		9,100,000		9,100,000	0
2017 Restructuring and Repositioning Plan, Restructuring Activities
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses									20,000,000
Restructuring expenses							19,400,000
2017 Restructuring and Repositioning Plan, Restructuring Activities | Discontinued operations
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses									9,000,000
Restructuring expenses							8,600,000
2017 Restructuring and Repositioning Plan, Restructuring Activities | SCC
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses									5,000,000
Restructuring expenses							4,600,000
2017 Restructuring and Repositioning Plan, Restructuring Activities | SBM
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses									3,000,000
Restructuring expenses							3,300,000
2017 Restructuring and Repositioning Plan, Restructuring Activities | Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring expenses							2,900,000
2017 Restructuring and Repositioning Plan, Restructuring Activities | Severance and other employee costs
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses									18,000,000
Restructuring expenses							17,600,000
2017 Restructuring and Repositioning Plan, Restructuring Activities | Asset impairments and facility exit costs
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses									2,000,000
Restructuring expenses							1,800,000
2017 Restructuring and Repositioning Plan, Restructuring Activities | Minimum | Corporate
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses									3,000,000
2017 Restructuring And Repositioning Plan, Repositioning Activities
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses									10,000,000
Restructuring expenses			1,100,000	$ 1,100,000	3,200,000	$ 1,500,000
Total cash payments					10,000,000		12,000,000
2017 Restructuring And Repositioning Plan, Repositioning Activities | Capital expenditures
Restructuring Cost and Reserve [Line Items]
Total cash payments					5,500,000		6,700,000
2017 Restructuring And Repositioning Plan, Repositioning Activities | Repositioning costs
Restructuring Cost and Reserve [Line Items]
Restructuring expenses							7,600,000
2017 Restructuring And Repositioning Plan, Repositioning Activities | Minimum | Capital expenditures
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses									10,000,000
2017 Restructuring And Repositioning Plan, Repositioning Activities | Maximum | Capital expenditures
Restructuring Cost and Reserve [Line Items]
Estimated transition expenses									$ 15,000,000
Total
Restructuring Cost and Reserve [Line Items]
Restructuring expenses					9,500,000
Total cash payments					8,500,000
Restructuring liability		$ 13,300,000	13,300,000		13,300,000		$ 13,300,000	$ 12,800,000
Repositioning | Capital expenditures
Restructuring Cost and Reserve [Line Items]
Total cash payments			0		0	1,900,000
Repositioning | Repositioning costs
Restructuring Cost and Reserve [Line Items]
Total cash payments			$ 0		$ 0	$ 4,200,000

Restructuring and Repositioni_4

Restructuring and Repositioning Expenses - Restructuring Expenses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses and asset impairments	$ 14.3	$ 2.5	$ 14	$ 19.9
Less: restructuring expenses and asset impairments reflected in discontinued operations	0	0.4	0.8	6.9
Total restructuring expenses and asset impairments from continuing operations	14.3	2.1	13.2	13
Severance and other employee costs
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses and asset impairments	10	2.1	9.3	19
Facility exit costs
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses and asset impairments	0.2	0	0.2	0.1
Asset impairments
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses and asset impairments	$ 4.1	$ 0.4	$ 4.5	$ 0.8

Restructuring and Repositioni_5

Restructuring and Repositioning Expenses - Restructuring Costs by Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses and asset impairments from continuing operations	$ 14.3	$ 2.1	$ 13.2	$ 13
Restructuring expenses and asset impairments reflected in discontinued operations	0	0.4	0.8	6.9
Total restructuring expenses and asset impairments	14.3	2.5	14	19.9
Operating Segments | SCC
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses and asset impairments from continuing operations	11.9	0.7	10.9	6.2
Operating Segments | SBM
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses and asset impairments from continuing operations	2.3	(0.3)	1.9	4.1
Corporate
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses and asset impairments from continuing operations	$ 0.1	$ 1.7	$ 0.4	$ 2.7

Restructuring and Repositioni_6

Restructuring and Repositioning Expenses - Restructuring Liability (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Restructuring Reserve [Roll Forward]
Balance, December 31, 2017			$ 12.8
Balance, September 30, 2018	$ 13.3		13.3
Restructuring costs and asset impairment charges, including discontinued operations	14.3	$ 2.5	14	$ 19.9
Other plans
Restructuring Reserve [Roll Forward]
Balance, December 31, 2017			1.1
Expense			0.7
Payments			(1.1)
Impact of foreign currency and other			(0.2)
Balance, September 30, 2018	0.5		0.5
Total
Restructuring Reserve [Roll Forward]
Balance, December 31, 2017			12.8
Expense			9.5
Payments			(8.5)
Impact of foreign currency and other			(0.5)
Balance, September 30, 2018	13.3		13.3
Severance and other employee costs
Restructuring Reserve [Roll Forward]
Restructuring costs and asset impairment charges, including discontinued operations	10	2.1	9.3	19
Severance and other employee costs | 2018 Plan
Restructuring Reserve [Roll Forward]
Balance, December 31, 2017			0
Expense			10.3
Payments			(1.2)
Impact of foreign currency and other			0
Balance, September 30, 2018	9.1		9.1
Severance and other employee costs | 2017 Plan
Restructuring Reserve [Roll Forward]
Balance, December 31, 2017			11.6
Expense			(1.7)
Payments			(6.1)
Impact of foreign currency and other			(0.3)
Balance, September 30, 2018	3.5		3.5
Facility exit costs | 2018 Plan
Restructuring Reserve [Roll Forward]
Balance, December 31, 2017			0
Expense			0
Payments			0
Impact of foreign currency and other			0
Balance, September 30, 2018	0		0
Facility exit costs | 2017 Plan
Restructuring Reserve [Roll Forward]
Balance, December 31, 2017			0.1
Expense			0.2
Payments			(0.1)
Impact of foreign currency and other			0
Balance, September 30, 2018	0.2		0.2
Asset impairments
Restructuring Reserve [Roll Forward]
Restructuring costs and asset impairment charges, including discontinued operations	$ 4.1	$ 0.4	$ 4.5	$ 0.8

Restructuring and Repositioni_7

Restructuring and Repositioning Expenses - Separation-Related Repositioning Expenses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Restructuring Cost and Reserve [Line Items]
Repositioning expenses	$ 3.7	$ 1.1	$ 5.8	$ 6.8
Repositioning
Restructuring Cost and Reserve [Line Items]
Repositioning expenses		0		5.3
Repositioning | Professional fees
Restructuring Cost and Reserve [Line Items]
Repositioning expenses		0		3.4
Repositioning | Software and IT implementation fees
Restructuring Cost and Reserve [Line Items]
Repositioning expenses		0		0.9
Repositioning | Employee-related costs
Restructuring Cost and Reserve [Line Items]
Repositioning expenses		$ 0		$ 1

Other Comprehensive (Loss) In_3

Other Comprehensive (Loss) Income - Pre-Tax, Tax, and After-Tax Components of Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
After-Tax Amount
Total other comprehensive (loss) income	$ (8.9)	$ 46.4	$ (27.6)	$ 62.6
Other comprehensive income attributable to GCP shareholders
Pre-Tax Amount
Other comprehensive (loss) income, pre-tax amount	(8.8)	46.7	(27.7)	62.6
Tax Benefit/ (Expense)
Other comprehensive (loss) income, tax	(0.1)	(0.3)	0.1	0
After-Tax Amount
Total other comprehensive (loss) income	(8.9)	46.4	(27.6)	62.6
Defined benefit pension and other postretirement plans
Pre-Tax Amount
Other comprehensive (loss) income, pre-tax amount	0.3	(0.3)	(0.5)	(0.3)
Tax Benefit/ (Expense)
Other comprehensive (loss) income, tax	(0.1)	0	0.1	0
After-Tax Amount
Total other comprehensive (loss) income	0.2	(0.3)	(0.4)	(0.3)
Currency translation adjustments
Pre-Tax Amount
Other comprehensive (loss) income, pre-tax amount	(9.1)	46.2	(27.3)	63
Tax Benefit/ (Expense)
Other comprehensive (loss) income, tax	0	0	0	0
After-Tax Amount
Total other comprehensive (loss) income	$ (9.1)	46.2	(27.3)	63
Gain (loss) from hedging activities
Pre-Tax Amount
Other comprehensive (loss) income, pre-tax amount		0.8	0.1	(0.1)
Tax Benefit/ (Expense)
Other comprehensive (loss) income, tax		(0.3)	0	0
After-Tax Amount
Total other comprehensive (loss) income		$ 0.5	$ 0.1	$ (0.1)

Other Comprehensive (Loss) In_4

Other Comprehensive (Loss) Income - Changes in Accumulated Other Comprehensive Income (Loss), Net of Tax (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)country	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)country	Sep. 30, 2017USD ($)
Changes in accumulated other comprehensive income (loss), net of tax
Beginning balance			$ 492	$ (139)
Total other comprehensive (loss) income	$ (8.9)	$ 46.4	(27.6)	62.6
Ending balance	$ 464.7	572.2	$ 464.7	572.2
Number of countries in which entity operates, more than | country	35		35
Defined Benefit Pension and Other Postretirement Plans
Changes in accumulated other comprehensive income (loss), net of tax
Beginning balance			$ 0.4	0.1
Other comprehensive (loss) income before reclassifications			(0.4)	(0.3)
Amounts reclassified from accumulated other comprehensive (loss) income			0	0
Total other comprehensive (loss) income	$ 0.2	(0.3)	(0.4)	(0.3)
Ending balance	0	(0.2)	0	(0.2)
Currency Translation Adjustments
Changes in accumulated other comprehensive income (loss), net of tax
Beginning balance			(86)	(147.7)
Other comprehensive (loss) income before reclassifications			(27.3)	63
Amounts reclassified from accumulated other comprehensive (loss) income			0	0
Total other comprehensive (loss) income	(9.1)	46.2	(27.3)	63
Ending balance	(113.3)	(84.7)	(113.3)	(84.7)
Hedging Activities
Changes in accumulated other comprehensive income (loss), net of tax
Beginning balance			(0.1)	0
Other comprehensive (loss) income before reclassifications			0.2	(0.7)
Amounts reclassified from accumulated other comprehensive (loss) income			(0.1)	0.6
Total other comprehensive (loss) income		0.5	0.1	(0.1)
Ending balance	0	(0.1)	0	(0.1)
Total
Changes in accumulated other comprehensive income (loss), net of tax
Beginning balance			(85.7)	(147.6)
Other comprehensive (loss) income before reclassifications			(27.5)	62
Amounts reclassified from accumulated other comprehensive (loss) income			(0.1)	0.6
Total other comprehensive (loss) income	(8.9)	46.4	(27.6)	62.6
Ending balance	$ (113.3)	$ (85)	$ (113.3)	$ (85)

Other Comprehensive (Loss) In_5

Other Comprehensive (Loss) Income - Narrative (Details)	Sep. 30, 2018country
Equity [Abstract]
Number of countries in which entity operates, more than	35

Stock Incentive Plans - Narrati

Stock Incentive Plans - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	Feb. 03, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock compensation (benefit) expense		$ (0.3)	$ 2	$ 4.6	$ 7.7
Amount of RSU's settled in cash				$ 1.2
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, exercise price, percent of market value on the date of grant				100.00%
Stock option awards, contractual term				5 years
Award vesting period	3 years
Intrinsic value of all options exercised		0.1	$ 0.2	$ 4.8	$ 8.3
Unrecognized stock-based compensation expense for stock options		1.3		$ 1.3
Unrecognized stock-based compensation expense for stock options, period of recognition				1 year
Stock Option | Vesting 1, Year 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	33.33%
Stock Option | Vesting 1, Year 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	33.33%
Stock Option | Vesting 1, Year 3
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	33.33%
Stock Option, 7 Year Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option awards, contractual term	7 years
Stock Option, 10 Year Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option awards, contractual term	10 years
Restricted Stock Units (RSUs) and Performance Based Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense for stock options, period of recognition				1 year 2 months
Total unrecognized compensation expense related to the RSU and PBU awards		$ 6.3		$ 6.3
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Amount settled in period (in shares)				115,932
Awards granted (in shares)				129,000
Weighted average grant date fair value (in usd per share)				$ 29.28
Number of shares forfeited				10,000
Restricted Stock Units (RSUs) | Vesting 1, Year 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	33.33%
Restricted Stock Units (RSUs) | Vesting 1, Year 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	33.33%
Restricted Stock Units (RSUs) | Vesting 1, Year 3
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	33.33%
Restricted Stock Units (RSUs) | Vesting 2, Year 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	0.00%
Restricted Stock Units (RSUs) | Vesting 2, Year 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	0.00%
Restricted Stock Units (RSUs) | Vesting 2, Year 3
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	100.00%
Sign-On Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	2 years
Award vesting percentage	100.00%
2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares repurchased				45,000	37,000
Number of shares of common stock available for issuance		8,300,000		8,300,000
2016 Stock Incentive Plan | Performance Based Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period						3 years
2016 Stock Incentive Plan | Performance Based Units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				3 years
Expected payout, percent of target						0.00%
2016 Stock Incentive Plan | Performance Based Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected payout, percent of target						200.00%
2017 Grant Date | Performance Based Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock compensation (benefit) expense		$ (2.8)
2017 Grant Date | 2016 Stock Incentive Plan | Performance Based Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				3 years
Weighted average grant date fair value (in usd per share)				$ 28.29
Number of shares forfeited				8,897
2016 Grant Date | 2016 Stock Incentive Plan | Performance Based Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value (in usd per share)				$ 17.04
Number of shares forfeited				0
2018 Grant Date | 2016 Stock Incentive Plan | Performance Based Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				3 years
Awards granted (in shares)				149,974
Weighted average grant date fair value (in usd per share)				$ 34.20
Number of shares forfeited				3,369

Stock Incentive Plans - Stock O

Stock Incentive Plans - Stock Options, Valuation Assumptions (Details) - Stock Option - $ / shares	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum	2.68%	1.83%
Risk-free interest rate, maximum	2.90%	2.10%
Volatility, minimum	27.91%	31.42%
Volatility, maximum	30.65%	31.96%
Dividend yield	0.00%	0.00%
Weighted average fair value per stock option (in usd per share)	$ 10.63	$ 9.16
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Average life of options (years)	5 years 6 months	5 years 6 months
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Average life of options (years)	6 years 6 months	6 years 6 months

Stock Incentive Plans - Stock_2

Stock Incentive Plans - Stock Option Activity (Details) - Stock Option - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Number Of Shares (in thousands)
Outstanding, beginning balance (in shares)	1,636
Options exercised (in shares)	314
Options forfeited (in shares)	25
Options granted (in shares)	241
Outstanding, end balance (in shares)	1,538	1,700	1,636
Exercisable, end of period (in shares)	968
Vested and expected to vest, end of period (in shares)	1,520
Weighted Average Exercise Price
Outstanding, beginning balance (in usd per share)	$ 18.94
Options exercised (in usd per share)	16.76
Options forfeited (in usd per share)	25.41
Options granted (in usd per share)	31.31
Outstanding, ending balance (in usd per share)	21.21		$ 18.94
Exercisable, end of period (in usd per share)	18.87
Vested and expected to vest, end of period (in usd per share)	$ 21.15
Other Disclosures
Outstanding, weighted-average remaining contractual term	3 years 11 months 27 days		3 years 9 months 11 days
Exercisable, weighted-average remaining contractual term	2 years 9 months 15 days
Vested and expected to vest, weighted-average remaining contractual term	3 years 11 months 17 days
Outstanding, aggregated intrinsic value	$ 9,262		$ 21,597
Exercisable, aggregated intrinsic value	7,339
Vested and expected to vest, aggregated intrinsic value	$ 9,222

Stock Incentive Plans - Restric

Stock Incentive Plans - Restricted Stock Units Award Activity (Details) - Restricted Stock Units (RSUs) shares in Thousands	9 Months Ended
	Sep. 30, 2018$ / sharesshares
Number Of Shares (in thousands)
Outstanding, beginning balance (in shares) | shares	406
RSUs settled (in shares) | shares	158
RSUs forfeited (in shares) | shares	10
RSUs granted (in shares) | shares	129
RSUs outstanding, ending balance (in shares) | shares	367
Weighted Average Grant Date Fair Value
Outstanding, beginning balance (in usd per share) | $ / shares	$ 19.15
RSUs settled (in usd per share) | $ / shares	18.36
RSUs forfeited (in used per share) | $ / shares	27.97
RSUs granted (in usd per share) | $ / shares	29.28
RSUs outstanding, ending balance (in usd per share) | $ / shares	$ 22.83

Stock Incentive Plans - PBUs, V

Stock Incentive Plans - PBUs, Valuation Assumptions (Details) - Performance Based Units	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected Term (Remaining Performance Period)	2 years 10 months 10 days	2 years 10 months 2 days
Expected volatility	28.56%	28.00%
Risk-free interest rate	2.38%	1.41%
Expected dividends	0.00%	0.00%
Correlation coefficient	38.98%	46.83%
Average correlation coefficient of constituents	39.96%	42.33%

Earnings Per Share - Earnings P

Earnings Per Share - Earnings Per Share Reconciliation (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerators
Income (loss) from continuing operations attributable to GCP shareholders		$ 7.2	$ (18.1)	$ (35.8)	$ (41.8)
Income from discontinued operations, net of income taxes		18.2	677.3	26.7	679.4
Net income (loss) attributable to GCP shareholders		$ 25.4	$ 659.2	$ (9.1)	$ 637.6
Denominators
Weighted average common shares—basic calculation		72.2	71.6	72.1	71.2
Dilutive effect of employee stock awards (in shares)		0.5	0	0	0
Weighted average common shares—diluted calculation	[1]	72.7	71.6	72.1	71.2
Basic earnings (loss) per share
Income (loss) from continuing operations attributable to GCP shareholders		$ 0.10	$ (0.25)	$ (0.50)	$ (0.59)
Income from discontinued operations, net of income taxes (in dollars per share)		0.25	9.46	0.37	9.54
Net income (loss) attributable to GCP shareholders (in dollars per share)	[2]	0.35	9.21	(0.13)	8.96
Diluted earnings (loss) per share
Income (loss) from continuing operations attributable to GCP shareholders (in dollars per share)	[1]	0.10	(0.25)	(0.50)	(0.59)
Income from discontinued operations, net of income taxes (in dollars per share)	[1]	0.25	9.46	0.37	9.54
Net income (loss) attributable to GCP shareholders (in dollars per share)	[1],[2]	$ 0.35	$ 9.21	$ (0.13)	$ 8.96
[1]	Dilutive effect only applicable to periods where there is income from continuing operations.
[2]	Amounts may not sum due to rounding.

Earnings Per Share - Narrative

Earnings Per Share - Narrative (Details) - USD ($) $ in Millions		3 Months Ended	9 Months Ended
		Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Treasury stock purchased	[1]		$ 1.3	$ 1
2016 Stock Incentive Plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Share repurchases (in shares)			45,000	37,000
Treasury stock purchased			$ 1.3	$ 1
Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options outstanding (in shares)		1,700,000	1,538,000	1,700,000	1,636,000
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
RSUs outstanding (in shares)		400,000	367,000	400,000	406,000
Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, treasury stock method (in shares)		0	0	0
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, treasury stock method (in shares)		0	0	0
[1]	During the nine months ended September 30, 2018 and 2017, GCP repurchased approximately 45,000 shares and 37,000 shares of Company common stock for $1.3 million and $1.0 million, respectively, in connection with its equity compensation programs.

Earnings Per Share - Dilutive E

Earnings Per Share - Dilutive Effect of Options and RSUs (Details) - shares shares in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	0.6	0.5	0.7
RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	0.4	0.2	0.4

Related Party Transactions an_2

Related Party Transactions and Transactions with Grace - Related Party Expenses and Agreements (Details) - W.R. Grace & Co. - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Indemnified receivables, tax	$ 7.2	$ 7.2
Indemnified payables, tax	$ 2.2	$ 2.7

Operating Segment and Geograp_3

Operating Segment and Geographic Information - Narrative (Details)	9 Months Ended
	Sep. 30, 2018segment
Segment Reporting [Abstract]
Number of operating segments	2

Operating Segment and Geograp_4

Operating Segment and Geographic Information - Schedule of Operating Segment Data (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net Sales
Net sales	$ 296.3	$ 282.4	$ 849.3	$ 794.9
Segment Operating Income
Operating income	47	45.8	115.4	125.1
Operating Segments
Segment Operating Income
Operating income	47	45.8	115.4	125.1
Operating Segments | Specialty Construction Chemicals
Net Sales
Net sales	165.4	156.2	487.4	449.1
Segment Operating Income
Operating income	12.7	15.7	31.2	44.5
Operating Segments | Specialty Building Materials
Net Sales
Net sales	130.9	126.2	361.9	345.8
Segment Operating Income
Operating income	$ 34.3	$ 30.1	$ 84.2	$ 80.6

Operating Segment and Geograp_5

Operating Segment and Geographic Information - Reconciliation of Operating Segment Data to Financial Statements (Details) - USD ($)	Apr. 10, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Operating income		$ 47,000,000	$ 45,800,000	$ 115,400,000	$ 125,100,000
Corporate costs		(67,300,000)	(76,300,000)	(219,800,000)	(221,900,000)
Currency and other financial losses in Venezuela				0	(40,100,000)
Repositioning expenses		3,700,000	1,100,000	5,800,000	6,800,000
Restructuring expenses and asset impairments		14,300,000	2,100,000	13,200,000	13,000,000
Gain on termination and curtailment of pension and other postretirement plans		0	17,100,000	100,000	5,800,000
Net income attributable to noncontrolling interests		100,000	100,000	300,000	200,000
Income (loss) from continuing operations before income taxes		14,900,000	(32,500,000)	(19,700,000)	(37,900,000)
Loss on debt refinancing	$ 59,800,000			59,800,000	0
Operating Segments
Segment Reporting Information [Line Items]
Operating income		47,000,000	45,800,000	115,400,000	125,100,000
Corporate
Segment Reporting Information [Line Items]
Corporate costs		(5,300,000)	(7,500,000)	(22,800,000)	(28,900,000)
Restructuring expenses and asset impairments		100,000	1,700,000	400,000	2,700,000
Segment Reconciling Items
Segment Reporting Information [Line Items]
Certain pension costs		(2,000,000)	(2,100,000)	(5,800,000)	(7,000,000)
Loss on sale of product line		0	0	0	(2,100,000)
Currency and other financial losses in Venezuela		0	(36,700,000)	0	(39,100,000)
Litigation settlement		0	(4,000,000)	0	(4,000,000)
Repositioning expenses		(3,700,000)	(1,100,000)	(5,800,000)	(6,800,000)
Restructuring expenses and asset impairments		(14,300,000)	(2,100,000)	(13,200,000)	(13,000,000)
Pension MTM adjustment and other related costs, net		0	(3,000,000)	(900,000)	(2,900,000)
Gain on termination and curtailment of pension and other postretirement plans		0	800,000	100,000	5,900,000
Third-party and other acquisition-related costs		(500,000)	(2,000,000)	(2,100,000)	(5,000,000)
Amortization of acquired inventory fair value adjustment		0	(200,000)	(200,000)	(2,900,000)
Tax indemnification adjustments		0	0	0	(2,400,000)
Net income attributable to noncontrolling interests		100,000	100,000	300,000	200,000
Other financing costs		0	(6,000,000)	0	(6,000,000)
Interest expense, net		(5,300,000)	(14,500,000)	(83,600,000)	(49,000,000)
Currency losses in Argentina		$ (1,100,000)	$ 0	$ (1,100,000)	0
Prior Segment - Darex | Corporate
Segment Reporting Information [Line Items]
Corporate costs					$ (5,400,000)

Operating Segment and Geograp_6

Operating Segment and Geographic Information - Geographic Area Data (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Net sales	$ 296.3	$ 282.4	$ 849.3	$ 794.9
Total North America
Segment Reporting Information [Line Items]
Net sales	154.1	141.5	426.4	396
United States
Segment Reporting Information [Line Items]
Net sales	144.4	132.5	402.4	374.2
Canada and Puerto Rico
Segment Reporting Information [Line Items]
Net sales	9.7	9	24	21.8
Europe Middle East Africa
Segment Reporting Information [Line Items]
Net sales	61.7	67	189.2	178.9
Asia Pacific
Segment Reporting Information [Line Items]
Net sales	63.9	58	181.6	168.4
Latin America
Segment Reporting Information [Line Items]
Net sales	$ 16.6	$ 15.9	$ 52.1	$ 51.6

Discontinued Operations - Narra

Discontinued Operations - Narrative (Details) - Disposed of by Sale - Darex - USD ($) $ in Millions	Jul. 03, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration received/receivable for disposal	$ 1,060
Gain recognized in 2018 after income taxes		$ 18.8	$ 683.7	$ 29.1	$ 683.7
Reduction in deferred consideration				55.1
Provision for income taxes of discontinued operations		6.2	$ 200	14.4	$ 200
Term of transition services agreement	24 months
Term of master tolling agreement	24 months
Indemnification payable		3.2		3.2		$ 3.3
Other current liabilities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal group, deferred consideration		13.1		13.1		55.1
Other Liabilities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal group, deferred consideration		$ 0.5		$ 0.5		$ 13.6
Minimum
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Term of delayed closings in foreign jurisdictions				4 months
Maximum
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Term of delayed closings in foreign jurisdictions				15 months

Discontinued Operations - Recon

Discontinued Operations - Reconciliation of Gain on Disposal (Details) - Darex - Disposed of by Sale - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net proceeds included in gain	$ 30.4	$ 1,000.2	$ 55.4	$ 1,000.2
Less: Transaction costs	0	15.9	0	15.9
Less: Net assets derecognized	5.4	100.6	11.9	100.6
Gain recognized before income taxes	25	883.7	43.5	883.7
Less: Tax effect of gain recognized	6.2	200	14.4	200
Gain recognized after income taxes	$ 18.8	$ 683.7	$ 29.1	$ 683.7

Discontinued Operations - Incom

Discontinued Operations - Income (Loss) From Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from discontinued operations, net of income taxes	$ 18.2	$ 677.3	$ 26.7	$ 679.4
Darex | Discontinued operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales	1.7	9.1	13.3	156.9
Cost of goods sold	1.2	6	13.9	104.6
Gross profit	0.5	3.1	(0.6)	52.3
Selling, general and administrative expenses	1.3	6.6	4.6	40.1
Research and development expenses	0	0.1	0	2.3
Restructuring and asset impairments	0	0.4	0.8	6.9
Gain on sale of business	(25)	(883.7)	(43.5)	(883.7)
Other (income) expenses, net	(0.1)	2.4	(3.2)	7.5
Total income	(23.8)	(874.2)	(41.3)	(826.9)
Income from discontinued operations before income taxes	24.3	877.3	40.7	879.2
Provision for income taxes	(6.1)	(200)	(14)	(199.7)
Less: Net income attributable to noncontrolling interests	0	0	0	(0.1)
Income from discontinued operations, net of income taxes	$ 18.2	$ 677.3	$ 26.7	$ 679.4

Discontinued Operations - Carry

Discontinued Operations - Carrying Amounts of Assets and Liabilities of Discontinued Operations (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Current assets held for sale	$ 3.1	$ 19.7
Non-current assets held for sale	0.9	2.8
Current liabilities held for sale	1.2	7.8
Non-current liabilities held for sale	0.3	0.3
Darex | Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Trade accounts receivable	1.7	8.4
Inventories	1.4	10.6
Other current assets	0	0.7
Current assets held for sale	3.1	19.7
Properties and equipment, net	0.4	2.2
Other assets	0.5	0.6
Non-current assets held for sale	0.9	2.8
Accounts payable	1.1	6.4
Other current liabilities	0.1	1.4
Current liabilities held for sale	1.2	7.8
Underfunded and unfunded defined benefit pension plans	0.3	0.3
Non-current liabilities held for sale	$ 0.3	$ 0.3

Acquisitions and Dispositions -

Acquisitions and Dispositions - Narrative (Details) - USD ($)	May 04, 2018	Oct. 31, 2017	May 17, 2017	Apr. 30, 2017	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill					$ 210,100,000		$ 210,100,000	$ 210,100,000	$ 198,200,000
Non-core Halex Net Assets | Disposed of by Sale
Business Acquisition [Line Items]
Proceeds from sale of assets				$ 3,000,000
Loss on disposal of assets				$ 2,100,000
Clydebridge Holdings | Subsidiaries
Business Acquisition [Line Items]
Percentage of stock acquired	100.00%
Clydebridge Holdings
Business Acquisition [Line Items]
Percentage of stock acquired	100.00%
Consideration transferred	$ 29,700,000
Cash acquired	10,000,000
Payments to acquire businesses	29,800,000
Working capital adjustments	100,000
Intangible assets	$ 10,700,000
Finite-lived intangible assets, weighted average amortization period	10 years
Escrow deposit disbursements							0
Goodwill	$ 19,900,000
Clydebridge Holdings | Customer Relationships
Business Acquisition [Line Items]
Intangible assets	$ 8,800,000
Finite-lived intangible assets, weighted average amortization period	9 years
Clydebridge Holdings | Trademarks and Trade Names
Business Acquisition [Line Items]
Intangible assets	$ 1,100,000
Finite-lived intangible assets, weighted average amortization period	10 years
Clydebridge Holdings | Technology-Based Intangible Assets
Business Acquisition [Line Items]
Intangible assets	$ 800,000
Finite-lived intangible assets, weighted average amortization period	15 years
Ductilcrete
Business Acquisition [Line Items]
Percentage of stock acquired		100.00%
Consideration transferred		$ 31,800,000
Cash acquired		$ 1,500,000
Intangible assets					15,500,000		15,500,000	15,500,000
Goodwill					14,000,000		$ 14,000,000	14,000,000	$ 14,000,000
Reduction in accounts receivable						$ 300,000
Reduction in consideration transferred						$ 300,000
Stirling Lloyd
Business Acquisition [Line Items]
Percentage of stock acquired			100.00%
Consideration transferred			$ 91,100,000
Cash acquired			$ 16,100,000
Businesses Acquired in 2017 and 2018
Business Acquisition [Line Items]
Net income					$ 3,100,000			$ 8,100,000

Acquisitions and Dispositions_2

Acquisitions and Dispositions - Schedule of Purchase Price Allocation (Details) - USD ($) $ in Millions	Sep. 30, 2018	May 04, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill	$ 210.1		$ 198.2
Clydebridge Holdings
Business Acquisition [Line Items]
Accounts receivable		$ 1.3
Inventories		0.6
Prepaid expenses and other current assets		0.1
Properties and equipment		0.1
Intangible assets		10.7
Goodwill		19.9
Accounts payable		(1)
Accrued liabilities		(0.1)
Deferred tax liabilities		(1.9)
Net assets acquired		$ 29.7
Ductilcrete
Business Acquisition [Line Items]
Accounts receivable	2.2
Other current assets	0.2
Properties and equipment	0.1
Intangible assets	15.5
Goodwill	14		$ 14
Accounts payable	(0.2)
Net assets acquired	$ 31.8