Supplemental Oil And Gas Information (Schedule Of Reserve Value By Category And The Respective Present Values, Before Income Taxes, Discounted At 10% As A Percentage Of Total Proved Reserves) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reserve Quantities [Line Items]
Total proved reserves year-end reserve report	$ 8,287	$ 40,417	$ 47,856
Proved developed producing reserves (PDP)	$ 7,686	$ 32,059	$ 34,440
% of PDP reserves to total proved reserves	93.00%	79.00%	72.00%
Proved developed non-producing reserves	$ 601	$ 2,956	$ 4,868
% of PDNP reserves to total proved reserves	7.00%	7.00%	10.00%
Proved undeveloped reserves (PUD)		$ 5,402	$ 8,548
% of PUD reserves to total proved reserves		14.00%	18.00%
Oil [Member]
Reserve Quantities [Line Items]
Total proved reserves year-end reserve report	$ 8,287	$ 40,417	$ 47,856
Proved developed producing reserves (PDP)	$ 7,686	$ 32,059	$ 34,440
% of PDP reserves to total proved reserves	93.00%	79.00%	72.00%
Proved developed non-producing reserves	$ 601	$ 2,956	$ 4,868
% of PDNP reserves to total proved reserves	7.00%	7.00%	10.00%
Proved undeveloped reserves (PUD)		$ 5,402	$ 8,548
% of PUD reserves to total proved reserves		14.00%	18.00%

Supplemental Oil And Gas Information (Schedule Of Reserve Value By Category And The Respective Present Values, Before Income Taxes, Discounted At 10% As A Percentage Of Total Proved Reserves) (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Reserve Quantities [Line Items]

Total proved reserves year-end reserve report

$ 8,287

$ 40,417

$ 47,856

Proved developed producing reserves (PDP)

$ 7,686

$ 32,059