Condensed Consolidated Statements of Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss	Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of ASC 842	$ 473.3	$ (0.3)	$ 0.0	$ 474.2	$ (0.3)	$ (0.9)	$ 0.0
Shares outstanding, beginning (in shares) at Dec. 31, 2018			40.4
Shareholders' equity, beginning at Dec. 31, 2018	473.3	(0.3)	$ 0.0	474.2	(0.3)	(0.9)	0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	11.6			11.6
Repurchase of common stock (in shares)			(0.3)
Repurchase of common stock	(25.0)		$ (4.7)	(20.3)
Taxes paid related to net share settlement of stock awards	(7.6)			(7.6)
Adoption of ASC 842	456.9	(0.3)	$ 0.0	457.8	(0.3)	(0.9)	0.0
Taxes paid related to net share settlement of stock awards (in shares)			(0.1)
Issuance of restricted stock awards, net of forfeitures (in shares)			0.1
Issuance of common stock (in shares)			0.1
Stock-based compensation	4.7		$ 4.7
Other	0.2			0.2
Shares outstanding, ending (in shares) at Mar. 31, 2019			40.2
Shareholders' equity, ending at Mar. 31, 2019	456.9		$ 0.0	457.8		(0.9)	0.0
Shares outstanding, beginning (in shares) at Dec. 31, 2018			40.4
Shareholders' equity, beginning at Dec. 31, 2018	473.3	(0.3)	$ 0.0	474.2	(0.3)	(0.9)	0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	133.5
Adoption of ASC 842	550.4	(0.3)	$ 0.0	551.3	(0.3)	(0.9)	0.0
Shares outstanding, ending (in shares) at Sep. 30, 2019			39.9
Shareholders' equity, ending at Sep. 30, 2019	550.4		$ 0.0	551.3		(0.9)	0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of ASC 842	456.9		$ 0.0	457.8		(0.9)	0.0
Shares outstanding, beginning (in shares) at Mar. 31, 2019			40.2
Shareholders' equity, beginning at Mar. 31, 2019	456.9		$ 0.0	457.8		(0.9)	0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	107.1			107.1
Repurchase of common stock (in shares)			(0.2)
Repurchase of common stock	(18.0)		$ (4.4)	(13.6)
Adoption of ASC 842	553.3		2.9	551.3		(0.9)	0.0
Stock-based compensation	7.4		7.4
Other	(0.1)		$ (0.1)
Shares outstanding, ending (in shares) at Jun. 30, 2019			40.0
Shareholders' equity, ending at Jun. 30, 2019	553.3		$ 2.9	551.3		(0.9)	0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of ASC 842	553.3		$ 2.9	551.3		(0.9)	0.0
Net (loss) income	14.8			14.8
Repurchase of common stock (in shares)			(0.2)
Repurchase of common stock	(25.0)		$ (10.4)	(14.6)
Taxes paid related to net share settlement of stock awards	(0.1)			(0.1)
Adoption of ASC 842	550.4		$ 0.0	551.3		(0.9)	0.0
Issuance of common stock (in shares)			0.1
Issuance of common stock	1.9		$ 1.9
Stock-based compensation	5.5
Other			$ 0.1	(0.1)
Shares outstanding, ending (in shares) at Sep. 30, 2019			39.9
Shareholders' equity, ending at Sep. 30, 2019	550.4		$ 0.0	551.3		(0.9)	0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of ASC 842	550.4		0.0	551.3		(0.9)	0.0
Adoption of ASC 842	511.0	(0.5)	$ 0.0	509.2	(0.5)	(0.9)	2.7
Shares outstanding, beginning (in shares) at Dec. 31, 2019			39.7
Shareholders' equity, beginning at Dec. 31, 2019	511.0	(0.5)	$ 0.0	509.2	(0.5)	(0.9)	2.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(23.5)			(23.4)			(0.1)
Repurchase of common stock (in shares)			(0.3)
Repurchase of common stock	(27.9)		$ (4.3)	(23.6)
Cash settlement of stock awards	(12.7)			(12.7)
Taxes paid related to net share settlement of stock awards	(15.1)			(15.1)
Adoption of ASC 842	435.6	(0.5)	0.0	433.9	(0.5)	(0.9)	2.6
Stock-based compensation	4.3		$ 4.3
Shares outstanding, ending (in shares) at Mar. 31, 2020			39.4
Shareholders' equity, ending at Mar. 31, 2020	435.6		$ 0.0	433.9		(0.9)	2.6
Shares outstanding, beginning (in shares) at Dec. 31, 2019			39.7
Shareholders' equity, beginning at Dec. 31, 2019	511.0	(0.5)	$ 0.0	509.2	(0.5)	(0.9)	2.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(99.2)
Adoption of ASC 842	511.0	$ (0.5)	$ 15.5	357.6	$ (0.5)	(0.9)	0.0
Shares outstanding, ending (in shares) at Sep. 30, 2020			39.5
Shareholders' equity, ending at Sep. 30, 2020	372.2		$ 15.5	357.6		(0.9)	0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of ASC 842	435.6		$ 0.0	433.9		(0.9)	2.6
Shares outstanding, beginning (in shares) at Mar. 31, 2020			39.4
Shareholders' equity, beginning at Mar. 31, 2020	435.6		$ 0.0	433.9		(0.9)	2.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(118.8)			(118.8)
Adoption of ASC 842	322.7		6.1	314.9		(0.9)	2.6
Stock-based compensation	6.1		$ 6.1
Other	(0.2)			(0.2)
Shares outstanding, ending (in shares) at Jun. 30, 2020			39.4
Shareholders' equity, ending at Jun. 30, 2020	322.7		$ 6.1	314.9		(0.9)	2.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of ASC 842	322.7		6.1	314.9		(0.9)	2.6
Net (loss) income	43.1			43.2			(0.1)
Adoption of ASC 842	322.7		$ 15.5	357.6		(0.9)	0.0
Purchase of noncontrolling interest	(3.0)			(0.5)			(2.5)
Issuance of common stock (in shares)			0.1
Issuance of common stock	2.5		$ 2.5
Stock-based compensation	6.9
Shares outstanding, ending (in shares) at Sep. 30, 2020			39.5
Shareholders' equity, ending at Sep. 30, 2020	372.2		$ 15.5	357.6		(0.9)	0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of ASC 842	$ 372.2		$ 15.5	$ 357.6		$ (0.9)	$ 0.0