Effective Tax Rates Calculation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 395,203	$ 324,671	$ 315,309
Income before income taxes	$ 1,145,901	$ 929,667	$ 869,332
Effective tax rate	34.50%	34.90%	36.30%