Income Tax - Schedule of Effective Income Tax Rate Reconciliation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income (loss) before income taxes	$ 8,525	$ (206,189)	$ (1,035,957)
Statutory rate	35.00%	35.00%	35.00%
Income tax benefit computed at statutory rate	$ 2,984	$ (72,166)	$ (362,585)
Reconciling items:
State income taxes		546	(21)
Other, net	50	854	795
Gain on acquisition of Eclipse Operating			(141)
Share-based compensation	(576)
Executive compensation limitation	496
Change in valuation allowance	(145,449)	71,312	287,786
Change in Federal tax rate	$ 142,495
Total income tax expense (benefit)		$ 546	$ (74,166)