Description Of Business And Significant Accounting Policies (Disaggregation Of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 1,367	$ 1,209
Crude Oil [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,357	1,203
Salt Water Disposal Fees [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 10	$ 6