Commitments And Contingencies (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2021 USD ($)
Trading Activity, Gains and Losses, Net [Line Items]
Contracted future purchases	$ 400.7
Railcar Operating Lease [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Lessee Operating Lease, Lease Not Yet Commenced	$ 1.7
Minimum [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Operating Lease Remaining Lease Term	1 year
Minimum [Member] | Railcar Operating Lease [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract	3 years
Maximum [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Operating Lease Remaining Lease Term	16 years 7 months 6 days
Maximum [Member] | Railcar Operating Lease [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract	5 years