Income Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
United States	$ 262,403	$ 640,604	$ 666,323
Foreign	50,848	45,133	32,994
Income before income taxes	$ 313,251	$ 685,737	$ 699,317