Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Net sales	$ 377,698	$ 364,768	$ 334,122
Cost of sales	241,922	233,626	217,133
Gross margin	135,776	131,142	116,989
Selling, engineering and administration	93,407	85,095	77,882
Operating earnings	42,369	46,047	39,107
Interest expense, net	1,217	1,135	1,098
Earnings before income taxes	41,152	44,912	38,009
Provision for income taxes	15,214	15,234	13,392
Net earnings	$ 25,938	$ 29,678	$ 24,617
Basic
from continuing operations (in dollars per share)	$ 1.80	$ 2.07	$ 1.71
Diluted:
from continuing operations (in dollars per share)	$ 1.80	$ 2.06	$ 1.70
Shares used in computation of earnings per share:
Basic (in shares)	14,379	14,307	14,362
Impact of dilutive securities (in shares)	68	71	78
Diluted (in shares)	14,447	14,378	14,440