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, 2014	$ 369.0	$ 526.8	$ 292.1	$ (429.2)	$ (23.8)	$ 3.1
Increase (Decrease) in Stockholders' Equity
Net income	52.7		52.7
Repurchase of common stock	(55.6)			(55.6)
Stock based compensation	1.3	1.3
Exercise of stock options	13.7	(28.9)		42.6
Other comprehensive income (loss)	(13.0)				(13.1)	0.1
Ending balance at Mar. 31, 2015	368.1	499.2	344.8	(442.2)	(36.9)	3.2
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	(2.9)		(2.7)			(0.2)
Repurchase of common stock	(15.0)			(15.0)
Stock based compensation	3.6	3.6
Exercise of stock options	13.8	(4.6)		18.4
Other comprehensive income (loss)	(6.1)				(8.7)	2.6
Distribution of GCP	188.9		57.3		135.3	(3.7)
Ending balance at Mar. 31, 2016	$ 394.8	$ 495.7	$ 490.9	$ (655.0)	$ 59.8	$ 3.4