Consolidated Statements of Operations (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement [Abstract]
Net sales	$ 96,271	$ 92,963	$ 275,429	$ 253,112
Cost of sales	59,806	59,860	175,182	165,126
Gross margin	36,465	33,103	100,247	87,986
Selling, engineering and administration	20,482	19,230	62,353	59,228
Operating earnings	15,983	13,873	37,894	28,758
Interest expense, net	273	264	875	844
Earnings before income taxes	15,710	13,609	37,019	27,914
Provision for income taxes	5,479	4,560	13,342	9,677
Net earnings	$ 10,231	$ 9,049	$ 23,677	$ 18,237
Earnings per share: (in dollars per share)
Basic	$ 0.71	$ 0.63	$ 1.67	$ 1.27
Diluted	$ 0.71	$ 0.63	$ 1.66	$ 1.26
Dividends declared per common share	$ 0.19	$ 0.18	$ 0.55	$ 0.52
Shares used in computation of earnings per share: (in shares)
Basic	14,312,847	14,371,718	14,177,483	14,353,700
Impact of dilutive securities	64,108	75,017	70,643	79,543
Diluted	14,376,955	14,446,735	14,248,126	14,433,243