Contingencies And Contractual Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Transportation and Storage Contracts, Fiscal Year Maturity
Next Twelve Months	$ 144,756
Year Two	138,893
Year Three	123,322
Year Four	109,083
Year Five	110,416
Thereafter	784,817
Total	1,411,287
Transportation and storage costs	143,300	$ 140,500	$ 135,100
Receivables, Long-term Contracts or Programs	8,000	$ 26,000
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	$ 20,000