Consolidated Statements of Stockholders' Equity (Deficit) (unaudited) - USD ($) $ in Millions	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive (Loss)
Beginning Balance (in shares) at Dec. 31, 2017		116,650,388	12,240,427
Beginning Balance at Dec. 31, 2017	$ 33.4	$ 1.2	$ (59.6)	$ 337.9	$ (244.5)	$ (1.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation expense	2.7			2.7
Issuance of common stock related to share-based compensation plans (in shares)		3,603
Issuance of common stock and stock warrants (in shares)		4,665,594
Issuance of common stock and stock warrants	19.3			19.3
Exercise of vested stock options (in shares)		100,012
Exercise of vested stock options	0.2			0.2
Dividends paid/accrued	(4.6)			(4.6)
Acquisition of treasury stock related to share-based compensation plans (in shares)			(362,402)
Acquisition of treasury stock related to share-based compensation plans	(1.9)		$ (1.9)
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)	(23.3)				(23.3)
Ending Balance (in shares) at Mar. 31, 2018		121,419,597	12,602,829
Ending Balance at Mar. 31, 2018	25.1	$ 1.2	$ (61.5)	355.5	(267.8)	(2.3)
Beginning Balance (in shares) at Dec. 31, 2017		116,650,388	12,240,427
Beginning Balance at Dec. 31, 2017	33.4	$ 1.2	$ (59.6)	337.9	(244.5)	(1.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net change on derivatives designated as cash flow hedges, net of tax	(0.2)
Foreign currency translation adjustments	(3.4)
Net income (loss)	(39.6)
Ending Balance (in shares) at Sep. 30, 2018		123,031,938	12,800,249
Ending Balance at Sep. 30, 2018	10.0	$ 1.2	$ (62.5)	360.6	(284.1)	(5.2)
Beginning Balance (in shares) at Mar. 31, 2018		121,419,597	12,602,829
Beginning Balance at Mar. 31, 2018	25.1	$ 1.2	$ (61.5)	355.5	(267.8)	(2.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation expense	5.2			5.2
Reclassification of equity award	1.3			1.3
Issuance of common stock related to share-based compensation plans (in shares)		289,500
Exercise of vested stock options (in shares)		1,017,576
Exercise of vested stock options	2.6			2.6
Dividends paid/accrued	(4.8)			(4.8)
Acquisition of treasury stock related to share-based compensation plans (in shares)			(134,898)
Acquisition of treasury stock related to share-based compensation plans	(1.0)		$ (1.0)
Forfeitures (in shares)			(18,945)
Net change on derivatives designated as cash flow hedges, net of tax	(0.4)					(0.4)
Foreign currency translation adjustments	(1.4)					(1.4)
Net income (loss)	(2.9)				(2.9)
Ending Balance (in shares) at Jun. 30, 2018		122,726,673	12,756,672
Ending Balance at Jun. 30, 2018	23.7	$ 1.2	$ (62.5)	359.8	(270.7)	(4.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation expense	4.9			4.9
Issuance of common stock related to share-based compensation plans (in shares)		6,993
Issuance of common stock related to share-based compensation plans	(0.1)			(0.1)
Exercise of vested stock options (in shares)		298,272
Exercise of vested stock options	0.8			0.8
Dividends paid/accrued	(4.8)			(4.8)
Acquisition of treasury stock related to share-based compensation plans (in shares)			(1,092)
Forfeitures (in shares)			(42,485)
Net change on derivatives designated as cash flow hedges, net of tax	0.4					0.4
Foreign currency translation adjustments	(1.5)					(1.5)
Net income (loss)	(13.4)				(13.4)
Ending Balance (in shares) at Sep. 30, 2018		123,031,938	12,800,249
Ending Balance at Sep. 30, 2018	10.0	$ 1.2	$ (62.5)	360.6	(284.1)	(5.2)
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]
Exercise of vested stock options (in shares)	2,393,014
Net change on derivatives designated as cash flow hedges, net of tax	$ (0.2)
Foreign currency translation adjustments	(0.7)
Net income (loss)	4.2
Ending Balance (in shares) at Sep. 30, 2019		126,166,326	13,301,751
Ending Balance at Sep. 30, 2019	14.8	$ 1.3	$ (67.3)	370.8	(285.6)	(4.4)
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)
Net change on derivatives designated as cash flow hedges, net of tax	0.1					0.1
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)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation expense	3.8			3.8
Issuance of common stock related to share-based compensation plans (in shares)		57,555
Exercise of vested stock options (in shares)		918,604
Exercise of vested stock options	4.3			4.3
Dividends paid/accrued	(5.2)			(5.2)
Acquisition of treasury stock related to share-based compensation plans (in shares)			(2,051)
Net change on derivatives designated as cash flow hedges, net of tax	(0.5)					(0.5)
Foreign currency translation adjustments	(1.2)					(1.2)
Net income (loss)	9.2				9.2
Ending Balance (in shares) at Sep. 30, 2019		126,166,326	13,301,751
Ending Balance at Sep. 30, 2019	$ 14.8	$ 1.3	$ (67.3)	$ 370.8	$ (285.6)	$ (4.4)