Income Taxes - Schedule of Provision for Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Current:
Federal	$ 8,792	$ 9,030	$ 16,762	$ 17,345
State and local	2,077	1,470	3,997	2,928
Foreign	2,415	1,498	3,529	3,043
Total current provision	13,284	11,998	24,288	23,316
Deferred:
Federal	(505)	(479)	341	1,060
State and local	(101)	(72)	29	94
Foreign	45	103	1,138	224
Total deferred provision	(561)	(448)	1,508	1,378
Provision for income taxes	$ 12,723	$ 11,550	$ 25,796	$ 24,694