Oil and Gas Properties - Net Capitalized Costs Related to Oil and Gas Producing Activities (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Extractive Industries [Abstract]
Unproved oil and gas properties	$ 84,032	$ 81,672
Proved oil and gas properties	109,960	81,412
Less: accumulated depreciation, depletion and amortization	(12,501)	(4,657)
Net carrying value of proved oil and gas properties	97,459	76,755
Net capitalized costs	$ 181,491	$ 158,427

Capitalized Costs Proved Properties Before Accumulated Depreciation Depletion And Amortization

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

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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

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

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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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