Commitment and Contingenices (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)
Loss Contingencies [Line Items]
Contingent Residual Support Agreement, Amount	$ 2,000,000
Estimated litigation liability	18,000
Accrued Environmental Loss Contingencies, Noncurrent	1,000
Contingent Residual Support Agreement
Loss Contingencies [Line Items]
Senior Notes	$ 1,000,000