Goodwill and Intangible Assets Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in Years)			13 years 9 months		14 years 2 months 8 days
Gross Carrying Amount	$ 333.5		$ 333.5		$ 333.5
Accumulated Amortization	51.4		51.4		$ 40.0
Intangible assets amortization expense	5.7	$ 5.6	$ 11.4	$ 11.3
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in Years)			13 years 9 months		14 years 3 months
Gross Carrying Amount	311.5		$ 311.5		$ 311.5
Accumulated Amortization	47.1		$ 47.1		$ 36.9
Trademarks and Trade Names
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in Years)			12 years 11 months		13 years 4 months 28 days
Gross Carrying Amount	21.8		$ 21.8		$ 21.8
Accumulated Amortization	4.1		$ 4.1		$ 3.0
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in Years)			1 year 3 months		2 years 2 months 12 days
Gross Carrying Amount	0.2		$ 0.2		$ 0.2
Accumulated Amortization	$ 0.2		$ 0.2		$ 0.1