Net Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Current deferred taxes, Assets	$ 135,120	$ 115,870
Current deferred taxes, Liabilities		(1,305)
Total deferred taxes-current	135,120	114,565
Noncurrent deferred taxes, Assets	92,383	85,792
Noncurrent deferred taxes, Liabilities	(408,283)	(368,006)
Total deferred taxes-noncurrent	(315,900)	(282,214)
Net deferred income tax liabilities	$ (180,780)	$ (167,649)