Other Intangible Assets, net (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Intangible assets, net
Weighted Average Life			10 years 5 months 6 days
Acquired Intangible Assets, Gross	$ 126.4		$ 126.4		$ 126.3
Accumulated Amortization	(74.9)		(74.9)		(72.2)
Acquired Intangible Assets, Net	51.5		51.5		54.1
Amortization expense related to other intangible assets included in depreciation and amortization	1.3	$ 1.3	$ 2.7	$ 4.5
Minimum
Intangible assets, net
Weighted Average Life			1 year
Maximum
Intangible assets, net
Weighted Average Life			14 years
Covenant not to compete
Intangible assets, net
Weighted Average Life			6 months 18 days
Acquired Intangible Assets, Gross	0.9		$ 0.9		0.9
Accumulated Amortization	(0.9)		(0.9)		(0.9)
Acquired Intangible Assets, Net	0.0		$ 0.0		0.0
Trade names and trademarks
Intangible assets, net
Weighted Average Life			1 year 18 days
Acquired Intangible Assets, Gross	9.8		$ 9.8		9.8
Accumulated Amortization	(9.7)		(9.7)		(9.7)
Acquired Intangible Assets, Net	0.1		$ 0.1		0.1
Proprietary know how
Intangible assets, net
Weighted Average Life			1 year 18 days
Acquired Intangible Assets, Gross	34.7		$ 34.7		34.6
Accumulated Amortization	(34.6)		(34.6)		(34.5)
Acquired Intangible Assets, Net	0.1		$ 0.1		0.1
Management contract rights
Intangible assets, net
Weighted Average Life			10 years 5 months 12 days
Acquired Intangible Assets, Gross	81.0		$ 81.0		81.0
Accumulated Amortization	(29.7)		(29.7)		(27.1)
Acquired Intangible Assets, Net	$ 51.3		$ 51.3		$ 53.9