Goodwill and Intangible Assets Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in Years)	13 years 11 months 12 days		14 years 2 months 8 days
Gross Carrying Amount	$ 333.5		$ 333.5
Accumulated Amortization	45.7		40.0
Intangible assets amortization expense	5.7	5.6
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in Years)	14 years 0 months 4 days		14 years 3 months
Gross Carrying Amount	311.5		311.5
Accumulated Amortization	42.0		36.9
Trademarks and Trade Names
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in Years)	13 years 2 months 8 days		13 years 4 months 28 days
Gross Carrying Amount	21.8		21.8
Accumulated Amortization	3.5		3.0
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in Years)	2 years		2 years 2 months 12 days
Gross Carrying Amount	0.2		0.2
Accumulated Amortization	$ 0.2		$ 0.1