Other Intangible Assets, net - Components of Intangible Assets, Net (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Finite Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	8 years 7 months 6 days
Intangible Assets, Gross	$ 110.1	$ 110.1
Accumulated Amortization	(53.5)	(47.0)
Intangible Assets, Net	$ 56.6	63.1
Covenant Not to Compete
Finite Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	1 year 9 months 18 days
Intangible Assets, Gross	$ 2.9	2.9
Accumulated Amortization	(2.1)	(1.3)
Intangible Assets, Net	$ 0.8	1.6
Trade Names and Trademarks
Finite Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	2 years 2 months 12 days
Intangible Assets, Gross	$ 0.9	0.9
Accumulated Amortization	(0.4)	(0.2)
Intangible Assets, Net	$ 0.5	0.7
Proprietary Know How
Finite Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	2 years 10 months 24 days
Intangible Assets, Gross	$ 3.8	3.8
Accumulated Amortization	(1.1)	(0.4)
Intangible Assets, Net	$ 2.7	3.4
Management Contract Rights
Finite Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	7 years 4 months 24 days
Intangible Assets, Gross	$ 81.0	81.0
Accumulated Amortization	(46.4)	(42.6)
Intangible Assets, Net	$ 34.6	38.4
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	12 years 2 months 12 days
Intangible Assets, Gross	$ 21.5	21.5
Accumulated Amortization	(3.5)	(2.5)
Intangible Assets, Net	$ 18.0	$ 19.0