Deferred Charges and Other Assets (Schedule Of Intangible and Other Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Assets [Abstract]
Turnaround Costs, Net	$ 40,416	$ 56,533
Other	5,820	4,371
Deferred charges and other assets, net	46,236	60,904
Other Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization	$ 17,866	$ 20,645	$ 22,831
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Other assets amortization period	5 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Other assets amortization period	15 years