Other Intangible Assets, net - Summary of Other Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	12 years 6 months
Acquired Intangible Assets, Gross	$ 200.3	$ 126.3
Accumulated Amortization	(34.3)	(72.2)
Acquired Intangible Assets, Net	$ 166.0	54.1
Covenant not to compete
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	4 years 10 months 24 days
Acquired Intangible Assets, Gross	$ 1.6	0.9
Accumulated Amortization	0.0	(0.9)
Acquired Intangible Assets, Net	$ 1.6	0.0
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	4 years 10 months 24 days
Acquired Intangible Assets, Gross	$ 6.3	9.8
Accumulated Amortization	(0.7)	(9.7)
Acquired Intangible Assets, Net	$ 5.6	0.1
Proprietary know how
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	5 years 8 months 12 days
Acquired Intangible Assets, Gross	$ 11.0	34.6
Accumulated Amortization	(0.8)	(34.5)
Acquired Intangible Assets, Net	$ 10.2	0.1
Management contract rights
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	10 years
Acquired Intangible Assets, Gross	$ 81.0	81.0
Accumulated Amortization	(32.2)	(27.1)
Acquired Intangible Assets, Net	$ 48.8	53.9
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	14 years 10 months 24 days
Acquired Intangible Assets, Gross	$ 100.4	0.0
Accumulated Amortization	(0.6)	0.0
Acquired Intangible Assets, Net	$ 99.8	$ 0.0
Minimum
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	6 months
Maximum
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life (Years)	16 years