Income Taxes - Summary of Changes in Deferred Tax Assets Valuation Allowance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Beginning Balance	$ 89,251	$ 1,044,152	$ 1,225,305
Credited to provision for income taxes	(15,981)	(954,487)	(203,051)
Charged (credited) to other comprehensive income and other	(3,677)	(414)	21,898
Ending Balance	$ 69,593	$ 89,251	$ 1,044,152