Income Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
United States	$ 640,604	$ 666,323	$ 535,265
Foreign	45,133	32,994	39,164
Income before income taxes	$ 685,737	$ 699,317	$ 574,429