Commitments And Contingencies (Narrative) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Trading Activity, Gains and Losses, Net [Line Items]
Asset	[1]	$ 1,698,218		$ 2,216,432
Liabilities		832,932		$ 1,153,443
Short-term lease expense		0
Contracted future purchases		$ 265,900
Minimum [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Lessee, Operating Lease, Term of Contract		1 year
Maximum [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Lessee, Operating Lease, Term of Contract		17 years 10 months 24 days
Restatement Adjustment [Member] | Accounting Standards Update 2016-02 [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Asset			$ 60,200
Liabilities			$ 60,200

[1] Asset balances by segment exclude intercompany payable and receivable balances