Leases Lessee, Schedule of Finance Leases (Details) $ in Millions	3 Months Ended				12 Months Ended
	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($) railcar	Dec. 31, 2019 USD ($) railcar	Dec. 31, 2018 USD ($)
Lessee, Lease, Description [Line Items]
Acquisition Costs, Period Cost					$ 40.0	$ 11.3	$ 0.0
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation	$ (0.3)				(0.3)	(0.1)
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Other Property, Plant, and Equipment, Net	37.5				37.5	8.9
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	17.8	$ 48.2	$ 37.0	$ 47.2	$ 125.3	$ 145.2	$ 170.7
Number of railcars received | railcar					732	157
Repayment of Long Term Finance Lease Obligations					$ 40.0
Railcars [Member]
Lessee, Lease, Description [Line Items]
Capital Leased Assets, Gross	$ 37.8				$ 37.8	$ 9.0