CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) shares in Millions, $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-In Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss	Noncontrolling Interests
Beginning Balance at Dec. 31, 2019	$ 2,334.7	$ (2.5)	$ 0.9	$ 1,205.7	$ 1,442.4	$ (2.5)	$ (318.1)	$ 3.8
Beginning Balance (in shares) at Dec. 31, 2019			91.2
Net income (loss)	(24.0)				(24.6)			0.6
Currency translation adjustments	(28.8)						(28.9)	0.1
Issuance of common stock for incentive stock programs, net of (payments of) taxes from withheld shares	3.8			3.8
Issuance of common stock for incentive stock programs, net of (payments of) taxes from withheld shares (in shares)			0.3
Stock-based compensation expense	12.9			12.9
Ending Balance at Jun. 30, 2020	2,296.1		$ 0.9	1,222.4	1,415.3		(347.0)	4.5
Ending Balance (in shares) at Jun. 30, 2020			91.5
Beginning Balance at Mar. 31, 2020	2,280.2		$ 0.9	1,212.7	1,419.8		(357.2)	4.0
Beginning Balance (in shares) at Mar. 31, 2020			91.4
Net income (loss)	(4.1)				(4.5)			0.4
Currency translation adjustments	10.3						10.2	0.1
Issuance of common stock for incentive stock programs, net of (payments of) taxes from withheld shares	1.9			1.9
Issuance of common stock for incentive stock programs, net of (payments of) taxes from withheld shares (in shares)			0.1
Stock-based compensation expense	7.8			7.8
Ending Balance at Jun. 30, 2020	2,296.1		$ 0.9	1,222.4	1,415.3		(347.0)	4.5
Ending Balance (in shares) at Jun. 30, 2020			91.5
Beginning Balance at Dec. 31, 2020	2,434.4		$ 0.9	1,234.0	1,382.6		(187.4)	4.3
Beginning Balance (in shares) at Dec. 31, 2020			91.6
Net income (loss)	55.5							0.1
Currency translation adjustments	(6.4)						(6.3)	(0.1)
Issuance of common stock for incentive stock programs, net of (payments of) taxes from withheld shares	(1.6)			(1.6)
Issuance of common stock for incentive stock programs, net of (payments of) taxes from withheld shares (in shares)			0.2
Stock-based compensation expense	12.2			12.2
Changes to noncontrolling interest	(0.6)							(0.6)
Ending Balance at Jun. 30, 2021	2,493.5		$ 0.9	1,244.6	1,438.0		(193.7)	3.7
Ending Balance (in shares) at Jun. 30, 2021			91.8
Beginning Balance at Mar. 31, 2021	2,448.8		$ 0.9	1,235.9	1,408.7		(200.3)	3.6
Beginning Balance (in shares) at Mar. 31, 2021			91.8
Net income (loss)	29.3				29.3
Currency translation adjustments	6.7						6.6	0.1
Issuance of common stock for incentive stock programs, net of (payments of) taxes from withheld shares	1.6			1.6
Stock-based compensation expense	7.1			7.1
Ending Balance at Jun. 30, 2021	$ 2,493.5		$ 0.9	$ 1,244.6	$ 1,438.0		$ (193.7)	$ 3.7
Ending Balance (in shares) at Jun. 30, 2021			91.8