CONDENSED CONSOLIDATED STATEMENT OF CHANGES IN EQUITY (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning balance (in shares) at Dec. 31, 2018		28.5
Beginning balance at Dec. 31, 2018	$ 572.7	$ 0.3	$ 1,777.9	$ (391.1)	$ (122.4)	$ (692.0)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	6.7			6.7
Other comprehensive income	4.7				4.7
Net settlement on vesting of equity awards (shares)		0.1
Net settlement on vesting of equity awards	1.8		1.8
Stock-based compensation charges	3.9		3.9
Employee stock purchase plan	0.6		0.6
Ending balance at Mar. 31, 2019	565.8	$ 0.3	1,780.6	(405.4)	(117.7)	(692.0)
Ending balance (in shares) at Mar. 31, 2019		28.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of new accounting pronouncement	(7.6)			(7.6)
Beginning balance (in shares) at Dec. 31, 2019		28.8
Beginning balance at Dec. 31, 2019	644.3	$ 0.3	1,796.9	(351.2)	(109.7)	(692.0)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	3.7			3.7
Other comprehensive income	(22.0)				(22.0)
Net settlement on vesting of equity awards (shares)		0.3
Net settlement on vesting of equity awards	2.5		2.5
Stock-based compensation charges	3.2		3.2
Employee stock purchase plan	0.6		0.6
Ending balance at Mar. 31, 2020	$ 619.9	$ 0.3	$ 1,798.2	$ (354.9)	$ (131.7)	$ (692.0)
Ending balance (in shares) at Mar. 31, 2020		29.1