Income Taxes - Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current tax provision:
U.S. Federal	$ (15,089)	$ 6,740	$ (18,905)
State and other	(1,520)	(418)	(2,182)
Total	(16,609)	6,322	(21,087)
Deferred tax provision:
U.S. Federal	1,382	(38,262)	184
State and other	(75)	(3,191)	53
Total	1,307	(41,453)	237
Income tax expense	$ (15,302)	$ (35,131)	$ (20,850)