Supplemental Oil And Gas Information (Schedule Of Capitalized Costs Related To Oil And Gas Producing Activities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Supplemental Oil And Gas Information [Abstract]
Proved oil and gas properties	$ 5,704	$ 5,315
Unproved properties		106
Total proved and unproved oil and gas properties	5,704	5,421
Less accumulated depreciation, depletion and amortization	(984)	(196)
Net oil and gas properties	$ 4,720	$ 5,225

Supplemental Oil And Gas Information [Abstract]

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- Definition

Amount of accumulated depreciation, depletion, amortization and valuation allowance relating to oil and gas producing activities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61901-109447

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- Definition

The sum of capitalized costs relating to oil and gas producing activities before accounting for accumulated depreciation.

+ References

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- Definition

Net amount of capitalized costs relating to oil and gas producing activities.

+ References

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- Definition

Capitalized costs of proved properties incurred for any combination mineral interests acquisitions; wells and related equipment; support equipment and facilities; and uncompleted wells and equipment and other costs not previously disclosed within this table.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Properties
-URI http://asc.fasb.org/extlink&oid=21914647

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 360
-Glossary Proved Properties
-URI http://asc.fasb.org/extlink&oid=6522428

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61901-109447

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- Definition

Capitalized costs of unproved properties incurred for any combination mineral interests acquisitions and other costs not previously disclosed within this table.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Properties
-URI http://asc.fasb.org/extlink&oid=21914647

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61901-109447

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-Glossary Unproved Properties
-URI http://asc.fasb.org/extlink&oid=6527831

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