Income Tax - Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax asset:
Oil and gas properties and equipment	$ 193,095	$ 235,884
Federal tax loss carryforwards	149,088	65,491
Derivative instruments and other	16,829
State effect of deferreds		540
Other, net	4,259	3,434
Deferred tax asset	363,271	305,349
Valuation allowance	(362,558)	(292,271)
Net deferred tax assets	713	13,078
Deferred tax liability:
Derivative instruments and other		12,054
Other, net	713	484
Net deferred tax liability	$ 713	12,538
Net deferred tax asset		$ 540