Selected Quarterly Financial Data (Unaudited) - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Selected Quarterly Financial Information [Line Items]
(Loss) gain on the sale of assets	$ (408,909)	$ (681)	$ 2,909	$ (175)	$ 3,760	$ 167	$ 282,064	$ (353)	$ (406,856)	$ 285,638	$ 92,291
Impairment of proved properties and other assets	87,941	502,233			$ 3,033		24,991		590,174	$ 28,024	$ 7,753
Virginia And West Virginia Property
Selected Quarterly Financial Information [Line Items]
(Loss) gain on the sale of assets	(407,700)								$ (407,700)
Conger Exchange Transaction
Selected Quarterly Financial Information [Line Items]
(Loss) gain on the sale of assets							$ 280,100
Northern Oklahoma and Legacy Shallow Northwest Pennsylvania Assets
Selected Quarterly Financial Information [Line Items]
Impairment of proved properties and other assets		$ 502,200
Texas Panhandle And South Texas
Selected Quarterly Financial Information [Line Items]
Impairment of proved properties and other assets	$ 87,900