Consolidated Statements of Equity (unaudited) - USD ($) $ in Millions		Total	Common Stock	Treasury Stock		Additional Paid-in Capital	Accumulated Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interests
Beginning balance (in shares) at Dec. 31, 2017			71,900,000	100,000
Beginning balance at Dec. 31, 2017		$ 492.0	$ 0.7	$ (3.4)		$ 29.9	$ 548.7	$ (85.7)	$ 1.8
Increase (Decrease) in Stockholders' Equity
Net income (loss)		(6.5)					(6.6)		0.1
Issuance of common stock in connection with stock plans (in shares)	[1]		100,000
Issuance of common stock in connection with stock plans	[1]	0.0
Share-based compensation		1.9				1.9
Exercise of stock options (in shares)			200,000
Exercise of stock options		$ 3.5				3.5
Share repurchases (in shares)		23,000		100,000	[2]
Share repurchases	[2]	$ (0.7)		$ (0.7)
Other comprehensive income (loss)		14.3						14.3
Ending balance (in shares) at Mar. 31, 2018			72,200,000	200,000
Ending balance at Mar. 31, 2018		504.5	$ 0.7	$ (4.1)		35.3	542.1	(71.4)	1.9
Increase (Decrease) in Stockholders' Equity
Cash payments for tax withholding obligations		0.7
Beginning balance (in shares) at Dec. 31, 2018			72,400,000	200,000
Beginning balance at Dec. 31, 2018		481.4	$ 0.7	$ (4.8)		39.6	563.9	(120.0)	2.0
Increase (Decrease) in Stockholders' Equity
Net income (loss)		21.6					21.4		0.2
Issuance of common stock in connection with stock plans (in shares)	[1]		300,000
Issuance of common stock in connection with stock plans	[1]	0.0
Share-based compensation		1.7				1.7
Exercise of stock options (in shares)			200,000
Exercise of stock options		$ 3.3				3.3
Share repurchases (in shares)		125,400		100,000	[2]
Share repurchases	[2]	$ (3.2)		$ (3.2)
Other comprehensive income (loss)		3.2						3.2
Ending balance (in shares) at Mar. 31, 2019			72,900,000	300,000
Ending balance at Mar. 31, 2019		508.0	$ 0.7	$ (8.0)		$ 44.6	$ 585.3	$ (116.8)	$ 2.2
Increase (Decrease) in Stockholders' Equity
Cash payments for tax withholding obligations		$ 3.2

[1] The par value of shares issued is not included in the table due to rounding.

[2] During the three months ended March 31, 2019 and 2018, GCP withheld and retained approximately 125,400 shares and 23,000 shares, respectively, of Company common stock in a non-cash transaction with a cost of $3.2 million and $0.7 million, respectively, in connection with fulfilling statutory tax withholding requirements for employees under the provisions of the Company's equity compensation programs. During the three months ended March 31, 2019 and 2018, cash payments for such tax withholding obligations were $3.2 million and $0.7 million, respectively.