Disclosures About Capitalized Costs, Costs Incurred (Details) (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Company:
Proved properties	$ 1,122	$ 4,949
Company [Member]
Company:
Unproved properties	0	0
Proved properties	1,122	4,949
Oil and Gas Property, Successful Effort Method, Gross, Total	1,122	4,949
Accumulated depreciation and depletion	(824)	(1,868)
Oil and gas property, successful efforts method	298	3,081
Company's Share of Piceance Energy [Member]
Company:
Unproved properties	15,872	15,763
Proved properties	183,937	168,378
Oil and Gas Property, Successful Effort Method, Gross, Total	199,809	184,141
Accumulated depreciation and depletion	(49,666)	(38,452)
Oil and gas property, successful efforts method	$ 150,143	$ 145,689

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Amount of accumulated depreciation, depletion and amortization of oil and gas property carried under the successful effort method. Oil and gas property include, but not limited to, the entity's wells and related equipment and facilities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 13

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Oil and Gas properties, gross, carried under the successful effort method.

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Oil and gas properties net of accumulated depreciation, depletion, amortization, impairment, and abandonment, carried under the successful effort method.

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Oil and Gas properties with proved reserves under the successful effort method.

+ References

Reference 1: 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

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Oil and Gas properties with unproved reserves under the successful effort method.

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