Consolidated Statements of Stockholders' Equity (Deficit) (unaudited) - USD ($) $ in Millions	Total	Previously Reported	Revision Of Prior Period, Accounting Standards Update, Adjustment	Revision Of Prior Period, Accounting Standards Update, Adjusted Balance	Common Stock	Common Stock Previously Reported	Common Stock Revision Of Prior Period, Accounting Standards Update, Adjusted Balance	Treasury Stock	Treasury Stock Previously Reported	Treasury Stock Revision Of Prior Period, Accounting Standards Update, Adjusted Balance	Additional Paid-In Capital	Additional Paid-In Capital Previously Reported	Additional Paid-In Capital Revision Of Prior Period, Accounting Standards Update, Adjusted Balance	Accumulated Deficit	Accumulated Deficit Previously Reported	Accumulated Deficit Revision Of Prior Period, Accounting Standards Update, Adjustment	Accumulated Deficit Revision Of Prior Period, Accounting Standards Update, Adjusted Balance	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Previously Reported	Accumulated Other Comprehensive Loss Revision Of Prior Period, Accounting Standards Update, Adjusted Balance
Beginning Balance (in shares) at Dec. 31, 2018					123,353,656			12,811,755
Beginning Balance at Dec. 31, 2018	$ 6.3				$ 1.2			$ (62.6)			$ 361.0			$ (289.8)				$ (3.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation expense	4.5										4.5
Issuance of common stock related to share-based compensation plans (in shares)					2,613
Exercise of vested stock options (in shares)					145,235
Exercise of vested stock options	0.4										0.4
Dividends paid/accrued	(5.0)										(5.0)
Acquisition of treasury stock related to share-based compensation plans (in shares)								(342,998)
Acquisition of treasury stock related to share-based compensation plans	(3.3)							$ (3.3)
Forfeitures (in shares)								(1,208)
Net change on derivatives designated as cash flow hedges, net of tax	0.2																	0.2
Foreign currency translation adjustments	0.5																	0.5
Net income (loss)	0.2													0.2
Ending Balance (in shares) at Mar. 31, 2019					123,501,504			13,155,961
Ending Balance at Mar. 31, 2019	3.8				$ 1.2			$ (65.9)			360.9			(289.6)				(2.8)
Beginning Balance (in shares) at Dec. 31, 2018					123,353,656			12,811,755
Beginning Balance at Dec. 31, 2018	6.3				$ 1.2			$ (62.6)			361.0			(289.8)				(3.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net change on derivatives designated as cash flow hedges, net of tax	0.3
Foreign currency translation adjustments	0.5
Net income (loss)	(5.0)
Ending Balance (in shares) at Jun. 30, 2019					125,190,167			13,299,700
Ending Balance at Jun. 30, 2019	4.4				$ 1.3			$ (67.3)			367.9			(294.8)				(2.7)
Beginning Balance (in shares) at Dec. 31, 2018					123,353,656			12,811,755
Beginning Balance at Dec. 31, 2018	6.3				$ 1.2			$ (62.6)			361.0			(289.8)				(3.5)
Ending Balance (in shares) at Dec. 31, 2019						127,807,546	127,807,546		13,786,266	13,786,266
Ending Balance at Dec. 31, 2019	$ 18.1	$ 18.1	$ (0.8)	$ 17.3		$ 1.3	$ 1.3		$ (73.6)	$ (73.6)		$ 372.7	$ 372.7		$ (277.8)	$ (0.8)	$ (278.6)		$ (4.5)	$ (4.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Beginning Balance (in shares) at Mar. 31, 2019					123,501,504			13,155,961
Beginning Balance at Mar. 31, 2019	$ 3.8				$ 1.2			$ (65.9)			360.9			(289.6)				(2.8)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation expense	4.8										4.8
Issuance of common stock related to share-based compensation plans (in shares)					359,488
Exercise of vested stock options (in shares)					1,329,175
Exercise of vested stock options	7.4				$ 0.1						7.3
Dividends paid/accrued	(5.1)										(5.1)
Acquisition of treasury stock related to share-based compensation plans (in shares)								(143,739)
Acquisition of treasury stock related to share-based compensation plans	(1.4)							$ (1.4)
Forfeitures (in shares)								0
Net change on derivatives designated as cash flow hedges, net of tax	0.1																	0.1
Foreign currency translation adjustments	0.0
Net income (loss)	(5.2)													(5.2)
Ending Balance (in shares) at Jun. 30, 2019					125,190,167			13,299,700
Ending Balance at Jun. 30, 2019	4.4				$ 1.3			$ (67.3)			367.9			(294.8)				(2.7)
Beginning Balance (in shares) at Dec. 31, 2019						127,807,546	127,807,546		13,786,266	13,786,266
Beginning Balance at Dec. 31, 2019	18.1	18.1	(0.8)	17.3		$ 1.3	$ 1.3		$ (73.6)	$ (73.6)		372.7	372.7		(277.8)	(0.8)	(278.6)		(4.5)	(4.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation expense	4.8										4.8
Issuance of common stock related to share-based compensation plans (in shares)					1,720
Exercise of vested stock options (in shares)					553,520
Exercise of vested stock options	3.1										3.1
Dividends paid/accrued	(5.4)										(5.4)
Acquisition of treasury stock related to share-based compensation plans (in shares)								(545)
Net change on derivatives designated as cash flow hedges, net of tax	(4.4)																	(4.4)
Foreign currency translation adjustments	(2.1)																	(2.1)
Net income (loss)	18.2													18.2
Ending Balance (in shares) at Mar. 31, 2020					128,362,786			13,786,811
Ending Balance at Mar. 31, 2020	31.5				$ 1.3			$ (73.6)			375.2			(260.4)				(11.0)
Beginning Balance (in shares) at Dec. 31, 2019						127,807,546	127,807,546		13,786,266	13,786,266
Beginning Balance at Dec. 31, 2019	$ 18.1	$ 18.1	$ (0.8)	$ 17.3		$ 1.3	$ 1.3		$ (73.6)	$ (73.6)		$ 372.7	$ 372.7		$ (277.8)	$ (0.8)	$ (278.6)		$ (4.5)	$ (4.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of vested stock options (in shares)	1,017,656
Net change on derivatives designated as cash flow hedges, net of tax	$ (3.6)
Foreign currency translation adjustments	(2.3)
Net income (loss)	33.3
Ending Balance (in shares) at Jun. 30, 2020					129,289,960			13,915,172
Ending Balance at Jun. 30, 2020	$ 46.1				$ 1.3			$ (74.7)			375.2			(245.3)				(10.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Beginning Balance (in shares) at Mar. 31, 2020					128,362,786			13,786,811
Beginning Balance at Mar. 31, 2020	$ 31.5				$ 1.3			$ (73.6)			375.2			(260.4)				(11.0)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation expense	4.4										4.4
Issuance of common stock related to share-based compensation plans (in shares)					463,038
Exercise of vested stock options (in shares)					464,136
Exercise of vested stock options	1.2										1.2
Dividends paid/accrued	(5.6)										(5.6)
Acquisition of treasury stock related to share-based compensation plans (in shares)								(128,361)
Acquisition of treasury stock related to share-based compensation plans	(1.1)							$ (1.1)
Net change on derivatives designated as cash flow hedges, net of tax	0.8																	0.8
Foreign currency translation adjustments	(0.2)																	(0.2)
Net income (loss)	15.1													15.1
Ending Balance (in shares) at Jun. 30, 2020					129,289,960			13,915,172
Ending Balance at Jun. 30, 2020	$ 46.1				$ 1.3			$ (74.7)			$ 375.2			$ (245.3)				$ (10.4)