Costs of Oil and Gas Properties (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Oil and Gas Property, Successful Effort Method, Gross [Abstract]
Proved properties	$ 2,585,279	$ 2,317,053
Unproved properties	99,634	86,224
Total capitalized costs	2,684,913	2,403,277
Accumulated depletion	(1,430,699)	(1,282,989)
Net capitalized costs	$ 1,254,214	$ 1,120,288

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.

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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.

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

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-Glossary Proved Properties

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

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