CONDENSED CONSOLIDATED STATEMENTS OF TOTAL EQUITY - USD ($) shares in Millions, $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-In Capital	Retained Earnings (Accumulated Deficit)	Retained Earnings (Accumulated Deficit) Cumulative Effect, Period of Adoption, Adjustment	Treasury Stock	Total Shareholders' Equity	Total Shareholders' Equity Cumulative Effect, Period of Adoption, Adjustment	Non-controlling Interest
BALANCE, beginning of period (in shares) at Dec. 31, 2019			16.7
BALANCE, beginning of period at Dec. 31, 2019	$ 369.6	$ (3.3)		$ 348.9	$ 31.1	$ (3.3)	$ (36.6)	$ 343.4	$ (3.3)	$ 26.2
Increase (Decrease) in Stockholders' Equity
Transfer of non-controlling interest				3.3				3.3		(3.3)
Stock-based compensation	2.6			3.7			(1.1)	2.6
Net income (loss)	(2.8)				(3.1)			(3.1)		0.3
BALANCE, end of period (in shares) at Mar. 31, 2020			16.7
BALANCE, end of period at Mar. 31, 2020	366.1			355.9	24.7		(37.7)	342.9		23.2
BALANCE, beginning of period (in shares) at Dec. 31, 2019			16.7
BALANCE, beginning of period at Dec. 31, 2019	369.6	$ (3.3)		348.9	31.1	$ (3.3)	(36.6)	343.4	$ (3.3)	26.2
Increase (Decrease) in Stockholders' Equity
Net income (loss)	3.7
BALANCE, end of period (in shares) at Jun. 30, 2020			16.7
BALANCE, end of period at Jun. 30, 2020	374.9			358.4	31.3		(37.9)	351.8		23.1
BALANCE, beginning of period (in shares) at Mar. 31, 2020			16.7
BALANCE, beginning of period at Mar. 31, 2020	366.1			355.9	24.7		(37.7)	342.9		23.2
Increase (Decrease) in Stockholders' Equity
Stock-based compensation	2.3			2.5			(0.2)	2.3
Net income (loss)	6.5				6.6			6.6		(0.1)
BALANCE, end of period (in shares) at Jun. 30, 2020			16.7
BALANCE, end of period at Jun. 30, 2020	374.9			358.4	31.3		(37.9)	351.8		23.1
BALANCE, beginning of period (in shares) at Dec. 31, 2020			16.7
BALANCE, beginning of period at Dec. 31, 2020	401.7			363.8	53.3		(37.9)	379.2		22.5
Increase (Decrease) in Stockholders' Equity
Stock-based compensation (in shares)			0.3
Stock-based compensation	(6.8)			2.9			(9.7)	(6.8)
Net income (loss)	(4.8)				(4.8)			(4.8)
BALANCE, end of period (in shares) at Mar. 31, 2021			17.0
BALANCE, end of period at Mar. 31, 2021	390.1			366.7	48.5		(47.6)	367.6		22.5
BALANCE, beginning of period (in shares) at Dec. 31, 2020			16.7
BALANCE, beginning of period at Dec. 31, 2020	401.7			363.8	53.3		(37.9)	379.2		22.5
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(25.3)
BALANCE, end of period (in shares) at Jun. 30, 2021			17.1
BALANCE, end of period at Jun. 30, 2021	379.7			381.4	28.2		(52.2)	357.4		22.3
BALANCE, beginning of period (in shares) at Mar. 31, 2021			17.0
BALANCE, beginning of period at Mar. 31, 2021	390.1			366.7	48.5		(47.6)	367.6		22.5
Increase (Decrease) in Stockholders' Equity
Stock-based compensation (in shares)			0.1
Stock-based compensation	10.1			14.7			(4.6)	10.1
Net income (loss)	(20.5)				(20.3)			(20.3)		(0.2)
BALANCE, end of period (in shares) at Jun. 30, 2021			17.1
BALANCE, end of period at Jun. 30, 2021	$ 379.7			$ 381.4	$ 28.2		$ (52.2)	$ 357.4		$ 22.3