Goodwill and Other Intangible Assets - Gross and Net Intangible Assets (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 40.0	$ 46.1
Accumulated Amortization	5.7	11.4
Net	34.3	34.7
Customer contracts
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	0.0	7.7
Accumulated Amortization	0.0	7.2
Net	$ 0.0	0.5
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted - Average Remaining Amortization Years	4 years
Gross Carrying Amount	$ 6.7	6.7
Accumulated Amortization	4.3	3.9
Net	$ 2.4	2.8
Permits
Finite-Lived Intangible Assets [Line Items]
Weighted - Average Remaining Amortization Years	22 years
Gross Carrying Amount	$ 31.7	31.7
Accumulated Amortization	1.4	0.3
Net	$ 30.3	31.4
Other
Finite-Lived Intangible Assets [Line Items]
Weighted - Average Remaining Amortization Years	30 years
Gross Carrying Amount	$ 1.6	0.0
Accumulated Amortization	0.0	0.0
Net	$ 1.6	$ 0.0