Income Taxes - Schedule of Provision for Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Current:
Federal	$ 6,358	$ 11,331	$ 23,119	$ 28,676
State and local	1,619	1,651	5,616	4,579
Foreign	2,502	1,191	6,036	4,234
Total current provision	10,479	14,173	34,771	37,489
Deferred:
Federal	(663)	(930)	(321)	130
State and local	(136)	(158)	(107)	(64)
Foreign	(477)	2	656	226
Total deferred provision	(1,276)	(1,086)	228	292
Provision for income taxes	$ 9,203	$ 13,087	$ 34,999	$ 37,781