Supplemental Oil And Gas Information (Schedule Of Standardized Measure Of Discounted Futures Net Cash Flows From Proved Oil And Gas Reserves) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental Oil And Gas Information [Abstract]
Future cash inflows	$ 38,566	$ 158,792	$ 183,801
Future production costs and taxes	(23,500)	(71,951)	(82,307)
Future development costs	(951)	(10,014)	(11,162)
Future income tax expenses		(13,092)	(18,910)
Future net cash flows	14,115	63,735	71,422
Discount at 10% for timing of cash flows	(5,828)	(29,204)	(32,714)
Standardized measure of discounted future net cash flows	$ 8,287	$ 34,531	$ 38,708	$ 45,354

Supplemental Oil And Gas Information [Abstract]

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Amount of estimated future accumulated cash inflow from the sale of proved oil and gas reserves.

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Amount of estimated future accumulated cash outflow for costs to be incurred in developing proved oil and gas reserves.

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Amount of estimated future accumulated cash outflow for income tax, based on the future income less future expense derived from production and sale of proved oil and gas reserves.

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Amount, after future accumulated cash outflow for development and production costs and future income tax, of estimated future accumulated cash inflow from the sale of proved oil and gas reserves.

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Amount of estimated future accumulated cash outflow for costs to be incurred in producing proved oil and gas reserves.

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Amount of discount on future accumulated cash inflow, after deducting future accumulated cash outflow for development and production costs and future income tax, from sale of proved oil and gas reserves, using a discount rate of ten percent a year.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 31
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62455-109447

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 30
-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62424-109447

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Amount of discounted future accumulated cash inflow relating to proved oil and gas reserves.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 30
-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62424-109447

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 55
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=34713648&loc=d3e63123-109448

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 35
-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62500-109447

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 31
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62455-109447

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