Summary of Significant Accounting Policies - Income Tax Expense (Benefit) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Tax Disclosure [Abstract]
Current provision	$ 687	$ (73)	$ 1,170	$ (36)
Deferred provision (benefit)	(31,333)	(417)	(146,118)	1,487
Provision for (benefit from) income taxes	$ (30,646)	$ (490)	$ (144,948)	$ 1,451