Components of Income Tax Provision (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal									$ 47,195	$ 37,076	$ 25,682
State									6,308	5,593	3,292
Foreign									4,331	5,034	3,674
Current Income Tax Expense (Benefit), Total									57,834	47,703	32,648
Deferred:
Federal									1,252	(1,490)	2,877
State									(300)	(375)	(341)
Foreign									580	160	629
Deferred Income Tax Expense (Benefit), Total									1,532	(1,705)	3,165
Total	$ 13,328	$ 16,387	$ 15,729	$ 13,922	$ 9,568	$ 13,106	$ 12,218	$ 11,106	$ 59,366	$ 45,998	$ 35,813