Supplemental Oil and Gas Disclosures - Results of Operations for Oil and Natural Gas Producing Activities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Oil and Gas Exploration and Production Industries Disclosures [Abstract]
Revenues	$ 625,233	$ 721,672	$ 1,304,004
Production costs	222,117	245,675	326,381
Depreciation, depletion and amortization	462,320	472,800	400,118
Exploration costs	1,785	2,369	3,064
Rig termination	0	3,895	0
Impairment	2,252	46,109	47,238
Income tax expense (benefit)	(23,665)	(18,382)	197,701
Results of operations for oil and natural gas producing activities	$ (39,576)	$ (30,794)	$ 329,502