Consolidated Income Statements (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Consolidated Income Statements [Abstract]
Net sales	$ 124,871	$ 123,527	$ 345,307	$ 350,985
Cost of sales	88,433	89,349	247,572	254,284
Gross profit	36,438	34,178	97,735	96,701
Research and development expenses	3,521	2,861	10,408	9,275
Selling, general and administrative expenses	23,383	21,852	69,015	67,116
Operating income	9,534	9,465	18,312	20,310
Interest Income (expense), net	(24)	(56)	(112)	(210)
Other income (expense), net	(65)	(353)	(515)	(771)
Income before provision for income taxes	9,445	9,056	17,685	19,329
Provision for income taxes	(2,595)	(1,972)	(4,050)	(4,297)
Net income	$ 6,850	$ 7,084	$ 13,635	$ 15,032
Earnings per share:
Basic	$ 0.46	$ 0.48	$ 0.91	$ 1.00
Diluted	$ 0.45	$ 0.47	$ 0.90	$ 0.98
Shares used in computing earnings per share:
Basic	14,984	14,887	14,931	14,963
Diluted	15,099	15,147	15,087	15,312