Income Taxes - Difference Between Total Tax Expense and Amount Computed by Applying Statutory Federal Income Tax Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Statutory rate applied to income	$ 376,019	$ 393,288	$ 391,209
Plus state income taxes, net of Federal tax benefit	29,211	32,295	32,646
Earnings in jurisdictions taxed at rates different from the statutory US tax rate	(18,057)	(13,684)	(3,453)
Foreign tax credit	(482)	(264)	(20,170)
Other	409	6,374	6,221
Income tax expense, total	$ 387,100	$ 418,009	$ 406,453