Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Net sales	$ 96,273	$ 99,388	$ 300,663	$ 281,928
Cost of sales	57,626	63,287	183,609	180,609
Gross margin	38,647	36,101	117,054	101,319
Selling, engineering and administration	24,705	22,477	75,384	68,460
Operating earnings	13,942	13,624	41,670	32,859
Interest expense, net	213	305	711	941
Earnings before income taxes	13,729	13,319	40,959	31,918
Provision for income taxes	4,937	4,992	14,777	11,463
Net earnings	$ 8,792	$ 8,327	$ 26,182	$ 20,455
Earnings per share:
Basic (in dollars per share)	$ 0.30	$ 0.29	$ 0.91	$ 0.71
Diluted (in dollars per share)	0.30	0.29	0.90	0.71
Dividends declared per common share (in dollars per share)	$ 0.115	$ 0.1	$ 0.315	$ 0.29
Shares used in computation of earnings per share:
Basic (in shares)	28,898,526	28,785,034	28,879,307	28,746,940
Impact of dilutive securities (in shares)	162,306	128,208	160,500	135,391
Diluted (in shares)	29,060,832	28,913,242	29,039,807	28,882,331