Derivatives And Fair Value (Effect Of Derivative Instruments On The Condensed Consolidated Statements Of Operations) (Details) - Not Designated as Hedging Instrument [Member] - Other, net [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Crude Oil Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 4,264
Crude Oil Puts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net		$ (1,032)	$ (1,711)