Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Retained Earnings (Accumulated Deficit)	Treasury Stock	Noncontrolling Interest
Beginning balance (deficit) at Dec. 31, 2019	$ 373.9	$ 0.0	$ 262.6	$ (2.7)	$ 169.5	$ (55.3)	$ (0.2)
Beginning balance (deficit) (in shares) at Dec. 31, 2019		22,950,360
Net income (loss)	(45.6)				(46.1)		0.5
Foreign currency translation	(0.2)			(0.2)
Change in fair value of interest rate collars	(2.8)			(2.8)
Issuance of performance stock units	0.0
Issuance of performance stock units (in shares)		46,701
Non-cash stock-based compensation	(2.9)		(2.9)
Repurchases of common stock	(15.3)					(15.3)
Distributions to noncontrolling interest	(0.5)						(0.5)
Ending balance (deficit) at Mar. 31, 2020	306.6		259.7	(5.7)	123.4	(70.6)	(0.2)
Ending balance (deficit) (in shares) at Mar. 31, 2020		22,997,061
Beginning balance (deficit) at Dec. 31, 2019	373.9	$ 0.0	262.6	(2.7)	169.5	(55.3)	(0.2)
Beginning balance (deficit) (in shares) at Dec. 31, 2019		22,950,360
Net income (loss)	(173.7)
Foreign currency translation	(0.3)
Repurchases of common stock	(15.3)
Ending balance (deficit) at Sep. 30, 2020	177.4		258.7	(5.2)	(3.8)	(70.6)	(1.7)
Ending balance (deficit) (in shares) at Sep. 30, 2020		23,086,792
Beginning balance (deficit) at Mar. 31, 2020	306.6		259.7	(5.7)	123.4	(70.6)	(0.2)
Beginning balance (deficit) (in shares) at Mar. 31, 2020		22,997,061
Net income (loss)	(39.8)				(39.1)		(0.7)
Foreign currency translation	(0.1)			(0.1)
Change in fair value of interest rate collars	0.2			0.2
Issuance of stock grants	0.5		0.5
Issuance of stock grants (in shares)		25,066
Non-cash stock-based compensation	0.4		0.4
Noncontrolling interest buyout	(1.7)		(1.7)
Distributions to noncontrolling interest	(0.4)						(0.4)
Ending balance (deficit) at Jun. 30, 2020	265.7		258.9	(5.6)	84.3	(70.6)	(1.3)
Ending balance (deficit) (in shares) at Jun. 30, 2020		23,022,127
Net income (loss)	(88.3)				(88.1)		(0.2)
Change in fair value of interest rate collars	0.4			0.4
Issuance of restricted stock units	0.0
Issuance of restricted stock units (in shares)		64,665
Non-cash stock-based compensation	(0.2)		(0.2)
Distributions to noncontrolling interest	(0.2)						(0.2)
Ending balance (deficit) at Sep. 30, 2020	177.4		258.7	(5.2)	(3.8)	(70.6)	(1.7)
Ending balance (deficit) (in shares) at Sep. 30, 2020		23,086,792
Beginning balance (deficit) at Dec. 31, 2020	$ 181.4		261.4	(4.4)	(3.3)	(70.6)	(1.7)
Beginning balance (deficit) (in shares) at Dec. 31, 2020	23,088,386	23,088,386
Net income (loss)	$ 3.9				2.3		1.6
Change in fair value of interest rate collars	0.4			0.4
Issuance of restricted stock units	0.0
Issuance of restricted stock units (in shares)		35,902
Issuance of performance stock units	0.0
Issuance of performance stock units (in shares)		81,136
Non-cash stock-based compensation	0.9		0.9
Distributions to noncontrolling interest	(0.4)						(0.4)
Ending balance (deficit) at Mar. 31, 2021	186.2		262.3	(4.0)	(1.0)	(70.6)	(0.5)
Ending balance (deficit) (in shares) at Mar. 31, 2021		23,205,424
Beginning balance (deficit) at Dec. 31, 2020	$ 181.4		261.4	(4.4)	(3.3)	(70.6)	(1.7)
Beginning balance (deficit) (in shares) at Dec. 31, 2020	23,088,386	23,088,386
Net income (loss)	$ 25.9
Ending balance (deficit) at Sep. 30, 2021	$ 211.3		265.9	(3.2)	19.5	(70.6)	(0.3)
Ending balance (deficit) (in shares) at Sep. 30, 2021	23,222,864	23,222,864
Beginning balance (deficit) at Mar. 31, 2021	$ 186.2		262.3	(4.0)	(1.0)	(70.6)	(0.5)
Beginning balance (deficit) (in shares) at Mar. 31, 2021		23,205,424
Net income (loss)	9.8				9.0		0.8
Foreign currency translation	0.1			0.1
Change in fair value of interest rate collars	0.4			0.4
Issuance of stock grants	0.5		0.5
Issuance of stock grants (in shares)		13,420
Non-cash stock-based compensation	1.6		1.6
Distributions to noncontrolling interest	(0.8)						(0.8)
Ending balance (deficit) at Jun. 30, 2021	197.8		264.4	(3.5)	8.0	(70.6)	(0.5)
Ending balance (deficit) (in shares) at Jun. 30, 2021		23,218,844
Net income (loss)	12.2				11.5		0.7
Foreign currency translation	(0.1)			(0.1)
Change in fair value of interest rate collars	0.4			0.4
Issuance of restricted stock units	0.0
Issuance of restricted stock units (in shares)		4,020
Non-cash stock-based compensation	1.5		1.5
Distributions to noncontrolling interest	(0.5)						(0.5)
Ending balance (deficit) at Sep. 30, 2021	$ 211.3		$ 265.9	$ (3.2)	$ 19.5	$ (70.6)	$ (0.3)
Ending balance (deficit) (in shares) at Sep. 30, 2021	23,222,864	23,222,864