Acquisitions and Dispositions - Additional Information (Detail) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended			6 Months Ended			12 Months Ended
	Jun. 30, 2014	Apr. 30, 2014	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Jun. 16, 2014	Dec. 31, 2014
Significant Acquisitions And Disposals [Line Items]
(Loss) gain on the sale of assets			$ 2,909		$ 282,064	$ 2,734	$ 281,711
Conger Exchange Transaction
Significant Acquisitions And Disposals [Line Items]
(Loss) gain on the sale of assets		$ 285,100
Cash proceeds from sale of assets		$ 145,000							$ 145,000
Net operating income prior to disposition	$ 2,100							$ 21,900
Sale and exchange transaction, closing date						Jun. 16, 2014
Selling expenses for property sale					5,000		5,000
Recognized revenue from sale of property interests acquire	$ 2,800
Miscellaneous Proved and Unproved Properties
Significant Acquisitions And Disposals [Line Items]
Proceeds from sale of oil and gas			3,600	$ 10,700	1,100		1,100
(Loss) gain on the sale of assets			$ 2,900	(175)	$ 1,600		$ 1,600
West Texas
Significant Acquisitions And Disposals [Line Items]
Proceeds from sale of oil and gas				$ 10,500