Income Taxes - Summary of (Benefit) Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Federal, Current	$ (19,856)	$ 60	$ (819)
Current State and Local Tax Expense (Benefit)	51	79	0
Foreign, Current	1,674	1,633	2,044
Current, Total	(18,131)	1,772	1,225
Federal, Deferred	(309,423)	5,081	3,505
State, Deferred	(1,431)	1,275	4,100
Foreign, Deferred	0	0	(1,107)
Deferred, Total	(310,854)	6,356	6,498
Income tax benefit (provision), total	$ (328,985)	$ 8,128	$ 7,723