Components of Income Tax Expense Benefit (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Current, Federal	$ 363,734	$ 248,172	$ 256,545
Current, Foreign	3,151	4,167	1,655
Current, State	38,987	23,224	28,490
Current, Total	405,872	275,563	286,690
Deferred, Federal	(15,912)	41,583	25,341
Deferred, Foreign	5,545
Deferred, State	(302)	7,525	3,278
Deferred, Total	(10,669)	49,108	28,619
Provision for income taxes	$ 395,203	$ 324,671	$ 315,309