Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended	9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Jun. 30, 2016	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 14,264	$ 25,565	$ 15,320	$ 21,426	$ 40,884	$ 55,149	$ 65,672
Effective income tax rate	31.90%			41.40%		30.30%	37.40%
Effective income tax rate reconciliation share based compensation excess tax benefit amount	$ 500					$ 9,000
Unrecognized tax benefits	31,800					31,800		$ 25,900
Decrease in unrecognized tax benefits is reasonably possible	$ 2,500					$ 2,500