Condensed Consolidated Statements of Earnings (unaudited) (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Condensed Consolidated Statements of Earnings (unaudited) [Abstract]
Net sales	$ 74,439	$ 63,910	$ 222,134	$ 185,271
Cost of sales	51,822	43,677	156,976	128,508
Gross margin	22,617	20,233	65,158	56,763
Operating expenses:
Selling expenses	4,042	4,023	12,331	11,496
Research and development expenses	648	793	2,257	2,331
General and administrative expenses	2,752	2,399	8,038	6,983
Operating Expenses	7,442	7,215	22,626	20,810
Earnings from operations	15,175	13,018	42,532	35,953
Other expenses (income):
Interest income	(39)	(72)	(179)	(212)
Interest expense	32	23	72	63
Other, net	(56)	122	(327)	(55)
Earnings before income tax expense	15,238	12,945	42,966	36,157
Income tax expense	4,453	4,452	13,697	12,296
Net earnings	$ 10,785	$ 8,493	$ 29,269	$ 23,861
Net earnings per common share - basic (in dollars per share)	$ 0.38	$ 0.30	$ 1.03	$ 0.86
Net earnings per common share - diluted (in dollars per share)	$ 0.36	$ 0.29	$ 0.97	$ 0.81