Components of Income Tax Expense Benefit (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Current, Federal	$ 195,862	$ 352,433	$ 368,957
Current, Foreign	13,699	10,625	8,513
Current, State	37,555	37,421	42,166
Current, Total	247,116	400,479	419,636
Deferred, Federal	(6,216)	(36,998)	(12,092)
Deferred, Foreign	(666)	24	2,463
Deferred, State	(3,592)	192	(820)
Deferred, Total	(10,474)	(36,782)	(10,449)
Provision for income taxes	$ 236,642	$ 363,697	$ 409,187