Other Intangible Assets, net - Components of Intangible Assets, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finite Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	9 years 1 month 6 days
Acquired Intangible Assets, Gross	$ 110.1	$ 200.3
Accumulated Amortization	(47.0)	(48.1)
Acquired Intangible Assets, Net	$ 63.1	152.2
Covenant Not to Compete
Finite Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	2 years 1 month 6 days
Acquired Intangible Assets, Gross	$ 2.9	2.9
Accumulated Amortization	(1.3)	(0.3)
Acquired Intangible Assets, Net	$ 1.6	2.6
Trade Names and Trademarks
Finite Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	2 years 10 months 24 days
Acquired Intangible Assets, Gross	$ 0.9	5.6
Accumulated Amortization	(0.2)	(1.2)
Acquired Intangible Assets, Net	$ 0.7	4.4
Proprietary Know How
Finite Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	3 years 8 months 12 days
Acquired Intangible Assets, Gross	$ 3.8	10.4
Accumulated Amortization	(0.4)	(2.0)
Acquired Intangible Assets, Net	$ 3.4	8.4
Management Contract Rights
Finite Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	8 years 1 month 6 days
Acquired Intangible Assets, Gross	$ 81.0	81.0
Accumulated Amortization	(42.6)	(37.4)
Acquired Intangible Assets, Net	$ 38.4	43.6
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	12 years 10 months 24 days
Acquired Intangible Assets, Gross	$ 21.5	100.4
Accumulated Amortization	(2.5)	(7.2)
Acquired Intangible Assets, Net	$ 19.0	$ 93.2