Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 12,064	$ 15,320
Effective income tax rate	24.90%	25.40%
Unrecognized tax benefits	$ 42,600		$ 37,100
Decrease in unrecognized tax benefits is reasonably possible	$ 3,800