Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net earnings	$ 40,005	$ 38,765	$ 33,277
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	9,641	9,291	8,559
Stock compensation expense	3,906	3,692	3,992
Shares issued under employee benefit plans	310	475	431
Deferred income tax expense	(92)	307	(669)
Provision for (recovery of) doubtful accounts	57	(27)	(225)
Foreign currency transaction loss (gain)	88	197	(25)
Gain on sale of a product line	0	0	(931)
Loss on impairment of assets	0	94	311
Changes in assets and liabilities
Accounts receivable	(7,642)	(2,697)	(2,744)
Inventories	(1,979)	(3,009)	(1,863)
Prepaid expenses and other current assets	(387)	(339)	43
Accounts payable and accrued expenses	5,775	739	2,645
Income taxes	3,890	(2,924)	(4,091)
Other	209	338	320
Net cash provided by operating activities	53,781	44,902	39,030
Cash flows from investing activities:
Proceeds from sale of a product line	0	0	1,125
Acquisition of a business	0	0	(4,661)
Capital expenditures	(13,883)	(6,612)	(7,557)
Proceeds from sale of property, plant and equipment	0	28	0
Intangible assets (acquired) disposed	(121)	(25)	44
Net cash used in investing activities	(14,004)	(6,609)	(11,049)
Cash flows from financing activities:
Proceeds from long-term debt	178	0	97
Principal payments on long-term debt	(1,386)	(3,557)	(1,458)
Proceeds from stock options exercised and restricted shares purchased	1,905	4,451	4,343
Excess tax benefits from stock compensation	2,862	2,894	4,230
Dividends paid	(11,703)	(4,311)	(3,091)
Purchase of treasury stock	(1,699)	(109)	(937)
Net cash (used in) provided by financing activities	(9,843)	(632)	3,184
Effect of exchange rate changes on cash	22	(133)	(344)
Increase in cash and cash equivalents	29,956	37,528	30,821
Cash and cash equivalents beginning of period	114,781	77,253	46,432
Cash and cash equivalents end of period	$ 144,737	$ 114,781	$ 77,253