Consolidated Condensed Statements of Operations (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Income Statement [Abstract]
Net sales	$ 71,808	$ 76,233
Cost of sales	46,771	47,369
Gross margin	25,037	28,864
Selling, engineering and administration	20,312	18,676
Operating earnings	4,725	10,188
Interest expense, net	248	205
Earnings before income taxes	4,477	9,983
Provision for income taxes	1,570	3,734
Net earnings	$ 2,907	$ 6,249
Earnings per share:
Basic	$ 0.21	$ 0.42
Diluted	$ 0.20	$ 0.42
Dividends declared - Common stock	$ 0.17	$ 0.16
Shares used in computation of earnings per share:
Basic	14,145,406	14,831,780
Impact of dilutive securities	91,351	65,837
Diluted	14,236,757	14,897,617