Summary of Significant Accounting Policies - Summary of Loss from Discontinued Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Revenues:
Oil and gas sales	$ 16,299
Costs and expenses:
Production taxes	693
Gathering and transportation	331
Lease operating	6,308
Depletion, depreciation and amortization	8,649
Interest expense	3,499	[1]
Total costs and expenses	19,480
Loss from discontinued operations before income taxes	(3,181)
Income tax benefit:
Current
Deferred	554
Total income tax benefit	554
Net loss from discontinued operations	$ (2,627)

[1] Interest expense was allocated to discontinued operations based on the ratio of the net assets of discontinued operations to our consolidated net assets plus long-term debt. Interest expense is net of capitalized interest of $2,010 for the three months ended March 31, 2013.