Consolidated Statements of Shareholders' Equity - USD ($) $ in Millions	Total	Revision of Prior Period, Accounting Standards Update, Adjustment	Common Stock	Paid-In Capital	Retained Deficit	Retained Deficit Revision of Prior Period, Accounting Standards Update, Adjustment	Accum. Other Comprehensive Income	Common Stock In Treasury
Balance at beginning of period at Dec. 31, 2018	$ 424.0		$ 0.5	$ 1,295.4	$ (641.0)		$ 244.9	$ (475.8)
Increase (Decrease) in Stockholders' Equity
Net income	65.3				65.3
Other comprehensive income (loss), net	(0.6)						(0.6)
Incentive plan activity	13.0			13.0
Long-term incentive compensation expense	10.8			10.8
Restricted stock and restricted stock unit vesting	(6.6)			(22.4)				15.8
Adjustment related to redeemable noncontrolling interest (Note 15)	5.6			5.6
Balance at end of period at Dec. 31, 2019	$ 511.5	$ (0.5)	0.5	1,302.4	(575.7)	$ (0.5)	244.3	(460.0)
Increase (Decrease) in Stockholders' Equity
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2016-13
Net income	$ 99.0				99.0
Other comprehensive income (loss), net	4.2						4.2
Incentive plan activity	17.5			17.5
Long-term incentive compensation expense	12.8			12.8
Restricted stock and restricted stock unit vesting	(4.4)			(12.8)				8.4
Adjustment related to redeemable noncontrolling interest (Note 15)	0.0
Balance at end of period at Dec. 31, 2020	640.1		0.5	1,319.9	(477.2)		248.5	(451.6)
Increase (Decrease) in Stockholders' Equity
Net income	425.4				425.4
Other comprehensive income (loss), net	15.4						15.4
Incentive plan activity	12.8			12.8
Long-term incentive compensation expense	14.2			14.2
Restricted stock and restricted stock unit vesting	(5.0)			(12.7)				7.7
Adjustment related to redeemable noncontrolling interest (Note 15)	0.0
Balance at end of period at Dec. 31, 2021	$ 1,102.9		$ 0.5	$ 1,334.2	$ (51.8)		$ 263.9	$ (443.9)