Goodwill and Other Intangible Assets - Gross and Net Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 200.6	$ 200.6
Accumulated Amortization	13.1	10.4
Total	$ 187.5	190.2
Customer contracts
Finite-Lived Intangible Assets [Line Items]
Weighted - Average Remaining Amortization (in years)	6 years
Gross Carrying Amount	$ 31.7	31.7
Accumulated Amortization	7.0	6.1
Total	$ 24.7	25.6
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted - Average Remaining Amortization (in years)	14 years
Gross Carrying Amount	$ 28.7	28.7
Accumulated Amortization	2.3	1.8
Total	$ 26.4	26.9
Permits
Finite-Lived Intangible Assets [Line Items]
Weighted - Average Remaining Amortization (in years)	26 years
Gross Carrying Amount	$ 139.0	139.0
Accumulated Amortization	3.2	1.9
Total	$ 135.8	137.1
Trade name
Finite-Lived Intangible Assets [Line Items]
Weighted - Average Remaining Amortization (in years)	3 years
Gross Carrying Amount	$ 1.2	1.2
Accumulated Amortization	0.6	0.6
Total	$ 0.6	$ 0.6