Stockholders' Equity - Components of Stockholders' Equity (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Beginning Balance	$ 192,237	$ 158,172	$ 185,766	$ 158,088
Issuance of common stock under stock plans, including tax effects	336	$ 6	2,470	$ 1,059
Repurchases of common stock	$ 2,673		$ 2,673
Repurchases of common stock, Shares	100,000	0	100,000	0
Stock-based compensation expense	$ 2,397	$ 2,464	$ 4,889	$ 5,266
Accounting Standards Update [Extensible List]				ASU No. 2016-13 [Member]
Net income	8,343	11,837	12,299	$ 11,324
Net change in interest rate swap, net of tax	139	45	329	(1,136)
Foreign currency translation	723	885	(1,578)	(1,035)
Ending Balance	201,502	173,409	201,502	173,409
Cumulative Effect, Period of Adoption, Adjustment [Member]
Beginning Balance				(157)
Common Stock [Member]
Beginning Balance	$ 238	$ 234	$ 236	$ 233
Beginning Balance, Shares	23,755,000	23,389,000	23,648,000	23,275,000
Issuance of common stock under stock plans, including tax effects	$ 0		$ 2	$ 1
Issuance of common stock under,stock plans including tax effects, Shares	25,000	12,000	132,000	126,000
Ending Balance	$ 238	$ 234	$ 238	$ 234
Ending Balance, Shares	23,780,000	23,401,000	23,780,000	23,401,000
Additional Paid-in Capital [Member]
Beginning Balance	$ 234,752	$ 220,308	$ 230,128	$ 216,454
Issuance of common stock under stock plans, including tax effects	(336)	6	2,468	1,058
Stock-based compensation expense	2,397	2,464	4,889	5,266
Ending Balance	237,485	222,778	237,485	222,778
Retained Earnings [Member]
Beginning Balance	131,937	117,477	127,981	118,147
Net income	8,343	11,837	12,299	11,324
Ending Balance	140,280	129,314	140,280	129,314
Retained Earnings [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Beginning Balance				(157)
Treasury Stock [Member]
Beginning Balance	$ (171,889)	$ (171,889)	$ (171,889)	$ (171,889)
Beginning Balance, Shares	4,631,000	4,631,000	4,631,000	4,631,000
Repurchases of common stock	$ 2,673		$ 2,673
Repurchases of common stock, Shares	63,000		63,000
Ending Balance	$ (174,562)	$ (171,889)	$ (174,562)	$ (171,889)
Ending Balance, Shares	4,694,000	4,631,000	4,694,000	4,631,000
Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance	$ (2,801)	$ (7,958)	$ (690)	$ (4,857)
Net change in interest rate swap, net of tax	139	45	329	(1,136)
Foreign currency translation	723	885	(1,578)	(1,035)
Ending Balance	$ (1,939)	$ (7,028)	$ (1,939)	$ (7,028)