Consolidated Statements of Shareholder's Equity (Unaudited) - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Shares	Additional Paid-in Capital	Additional Paid-in Capital Cumulative Effect, Period of Adoption, Adjustment	Retained Deficit	Retained Deficit Cumulative Effect, Period of Adoption, Adjustment	Treasury Shares	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2020	$ 507.5			$ 843.4		$ (363.4)		$ (12.9)	$ 40.4
Beginning balance (in shares) at Dec. 31, 2020			45,164,308
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	9.8					9.8
Other comprehensive income (loss)	(1.4)								(1.4)
Stock-based compensation expense	1.8			1.8
Stock option activity	2.5			2.5
Issuance of treasury shares				(12.4)				12.4
Issuance of treasury shares (in shares)			580,248
Shares surrendered for taxes	(0.5)							(0.5)
Shares surrendered for taxes (in shares)			(72,174)
Ending balance at Mar. 31, 2021	513.3	$ (6.4)		824.7	$ (10.6)	(349.4)	$ 4.2	(1.0)	39.0
Ending balance (in shares) at Mar. 31, 2021			45,672,382
Beginning balance at Dec. 31, 2020	507.5			843.4		(363.4)		(12.9)	40.4
Beginning balance (in shares) at Dec. 31, 2020			45,164,308
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	63.8
Other comprehensive income (loss)	(2.5)
Ending balance at Jun. 30, 2021	570.0			827.5		(295.4)			37.9
Ending balance (in shares) at Jun. 30, 2021			46,088,954
Beginning balance at Mar. 31, 2021	513.3	$ (6.4)		824.7	$ (10.6)	(349.4)	$ 4.2	(1.0)	39.0
Beginning balance (in shares) at Mar. 31, 2021			45,672,382
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	54.0					54.0
Other comprehensive income (loss)	(1.1)								(1.1)
Stock-based compensation expense	1.8			1.8
Stock-based compensation expense (in shares)			178,886
Stock option activity	0.7			0.7
Stock option activity (in shares)			66,615
Issuance of treasury shares				(1.0)				1.0
Issuance of treasury shares (in shares)			57,845
Convertible notes settlement (in shares)			113,226
Convertible notes settlement	1.3			1.3
Ending balance at Jun. 30, 2021	570.0			827.5		(295.4)			37.9
Ending balance (in shares) at Jun. 30, 2021			46,088,954
Beginning balance at Dec. 31, 2021	664.6			832.1		(188.2)			20.7
Beginning balance (in shares) at Dec. 31, 2021			46,268,855
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	37.1					37.1
Other comprehensive income (loss)	(1.9)								(1.9)
Stock-based compensation expense	2.1			2.1
Stock-based compensation expense (in shares)			298,648
Stock option activity	6.3			6.3
Stock option activity (in shares)			406,750
Purchase of treasury shares	(3.4)							(3.4)
Purchase of treasury shares (in Shares)			(169,816)
Shares surrendered for taxes	(1.6)			(0.2)				(1.4)
Shares surrendered for taxes (in shares)			(91,853)
Ending balance at Mar. 31, 2022	703.2			840.3		(151.1)		(4.8)	18.8
Ending balance (in shares) at Mar. 31, 2022			46,712,584
Beginning balance at Dec. 31, 2021	664.6			832.1		(188.2)			20.7
Beginning balance (in shares) at Dec. 31, 2021			46,268,855
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	111.6
Other comprehensive income (loss)	(5.0)
Ending balance at Jun. 30, 2022	768.9			843.9		(76.6)		(14.1)	15.7
Ending balance (in shares) at Jun. 30, 2022			46,411,393
Beginning balance at Mar. 31, 2022	703.2			840.3		(151.1)		(4.8)	18.8
Beginning balance (in shares) at Mar. 31, 2022			46,712,584
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	74.5					74.5
Other comprehensive income (loss)	(3.1)								(3.1)
Stock-based compensation expense	2.2			2.2
Stock-based compensation expense (in shares)			44,157
Stock option activity	1.5			1.5
Stock option activity (in shares)			92,290
Purchase of treasury shares	(9.3)							(9.3)
Purchase of treasury shares (in Shares)			(437,638)
Issuance of treasury shares				(0.1)				0.1
Issuance of treasury shares (in shares)			2,285
Shares surrendered for taxes	(0.1)							(0.1)
Shares surrendered for taxes (in shares)			(2,285)
Ending balance at Jun. 30, 2022	$ 768.9			$ 843.9		$ (76.6)		$ (14.1)	$ 15.7
Ending balance (in shares) at Jun. 30, 2022			46,411,393