Consolidated Statements of Equity (unaudited) - USD ($) $ in Millions	Total	Common Stock and Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Beginning balance at Dec. 31, 2015	$ 212.5	$ 496.7	$ 436.3	$ (658.4)	$ (66.8)	$ 4.7
Increase (Decrease) in Stockholders' Equity
Net income	78.5		78.8			(0.3)
Repurchase of common stock	(55.1)			(55.1)
Stock-based compensation	9.2	9.2
Exercise of stock options	23.7	(16.2)		39.9
Tax benefit related to stock plans	70.4		70.4
Shares issued	0.7	0.7
Other comprehensive (loss) income	(7.5)				(10.1)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest	(2.6)
Dividends declared	(24.1)		(24.1)
Distribution of GCP	186.3		54.7		135.3	(3.7)
Ending balance at Sep. 30, 2016	494.6	490.4	616.1	(673.6)	58.4	3.3
Beginning balance at Dec. 31, 2016	372.4	488.0	619.3	(804.9)	66.4	3.6
Increase (Decrease) in Stockholders' Equity
Net income	133.5		134.2			(0.7)
Repurchase of common stock	(65.0)			(65.0)
Payments to taxing authorities in consideration of employee tax obligations relative to stock-based compensation arrangements	(2.5)	(2.5)
Stock-based compensation	8.2	8.2
Exercise of stock options	14.4	(18.3)		32.7
Shares issued	0.7	0.7
Other comprehensive (loss) income	(22.7)				(22.7)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest	0.0
Contribution to joint venture	1.2					1.2
Dividends declared	43.2		43.2
Ending balance at Sep. 30, 2017	$ 397.0	$ 476.1	$ 710.3	$ (837.2)	$ 43.7	$ 4.1