Consolidated Condensed Statements of Operations (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Income Statement [Abstract]
Net sales	$ 87,130	$ 69,698	$ 245,337	$ 202,205
Cost of sales	52,800	46,918	151,942	131,768
Gross margin	34,330	22,780	93,395	70,437
Selling, engineering and administration	20,219	14,791	57,741	44,933
Operating earnings	14,111	7,989	35,654	25,504
Interest expense (income)	286	(87)	729	121
Earnings before income taxes	13,825	8,076	34,925	25,383
Provision for income taxes	4,968	1,196	12,377	7,409
Net earnings	$ 8,857	$ 6,880	$ 22,548	$ 17,974
Earnings per share:
Basic	$ 0.63	$ 0.46	$ 1.57	$ 1.20
Diluted	$ 0.62	$ 0.46	$ 1.56	$ 1.19
Dividends declared - Common stock	$ 0.17	$ 0.16	$ 0.49	$ 0.44
Shares used in computation of earnings per share:
Basic	14,128,055	14,989,366	14,393,644	14,959,202
Impact of dilutive securities	57,851	69,109	65,140	84,339
Diluted	14,185,906	15,058,475	14,458,784	15,043,541