Income Taxes - Deferred Tax Balance Classification in Balance Sheet (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Current deferred tax assets	$ 0	$ 9,585
Current deferred tax liabilities	0	(672)
Net current deferred taxes	0	8,913
Long term deferred tax assets	2,433	1,639
Long term deferred tax liabilities	(668,580)	(715,067)
Net long term deferred taxes		(713,428)
Net deferred tax liabilities	$ (666,147)	$ (704,515)