Income Taxes - Income Tax Reconciliation Computed at Federal Statutory Rates to Income Tax Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Tax Disclosure [Abstract]
Provision for income taxes at statutory rate	$ 3,678	$ 3,180	$ 6,641	$ 7,001
State and local income taxes, net of federal tax benefit	151	130	271	287
Share based compensation	54	30	95	62
Reversal of reserves				(342)
Foreign rate differential	(156)	(99)	(257)	(186)
Research credits	(90)		(159)
Permanent non-deductible acquisition-related expense	258		419
Other, net	(38)	(58)	(46)	(80)
Reported income tax provision	$ 3,857	$ 3,183	$ 6,964	$ 6,742
Provision for income taxes at statutory rate, tax rate	35.00%	35.00%	35.00%	35.00%
State and local income taxes, net of federal tax benefit, tax rate	1.40%	1.40%	1.40%	1.40%
Share based compensation, tax rate	0.50%	0.30%	0.50%	0.30%
Reversal of reserves, tax rate				(1.70%)
Foreign rate differential, tax rate	(1.50%)	(1.10%)	(1.40%)	(0.90%)
Research credits, tax rate	(0.80%)		(0.90%)
Permanent non-deductible acquisition-related expense, tax rate	2.50%		2.20%
Other, net, tax rate	(0.40%)	(0.60%)	(0.10%)	(0.40%)
Reported income tax provision, tax rate	36.70%	35.00%	36.70%	33.70%