Derivatives And Fair Value (Effect Of Derivative Instruments On The Condensed Consolidated Statements Of Operations) (Details) - Crude Oil Swaps [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, gain (loss)	$ (1,912)
Realized Gain - Contract Settlements [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, gain (loss)	1,131
Unrealized Loss [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, gain (loss)	$ (3,043)