Derivative And Financial Instruments (Changes In Fair Value) (Details) - Commodity Contract $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) item	Dec. 31, 2018 USD ($)
Derivative Instruments Gain Loss [Line Items]
Beginning fair value of commodity derivatives	$ 3,914	$ 1,231
Net gain (loss) on derivatives	(3,772)	1,316
Ending fair value of commodity derivatives	$ (759)	3,914
Number of counterparties | item	3
Oil reserves
Derivative Instruments Gain Loss [Line Items]
Net gain (loss) on derivatives	$ (4,031)	1,400
Net settlements paid (received) on derivative contracts		1,330
Net settlements paid (received) on derivative contracts	(807)
Natural gas
Derivative Instruments Gain Loss [Line Items]
Net gain (loss) on derivatives	259	(84)
Net settlements paid (received) on derivative contracts		$ 37
Net settlements paid (received) on derivative contracts	$ (94)