Consolidated Statements of Earnings - Unaudited - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Net sales	$ 118,859	$ 106,243	$ 350,410	$ 312,083
Cost of goods sold	76,777	68,705	228,082	204,527
Gross Margin	42,082	37,538	122,328	107,556
Selling, general and administrative expenses	18,450	15,915	55,441	46,970
Research and development expenses	6,517	6,380	19,500	18,432
Restructuring charges	997	1,435	3,364	2,942
Gain (Loss) on Disposition of Property Plant Equipment	0	(697)	(2)	(698)
Operating earnings	16,118	13,111	44,021	38,514
Other income (expense):
Interest expense	(489)	(773)	(1,601)	(2,209)
Interest income	413	363	1,367	914
Other (expense) income, net	(1,687)	1,258	(2,557)	2,889
Total other (expense) income	(1,763)	848	(2,791)	1,594
Earnings before income taxes	14,355	13,959	41,230	40,108
Income tax expense	4,144	4,340	12,262	12,039
Net earnings	$ 10,211	$ 9,619	$ 28,968	$ 28,069
Earnings per share:
Basic (in dollars per share)	$ 0.31	$ 0.29	$ 0.88	$ 0.85
Diluted (in dollars per share)	$ 0.30	$ 0.29	$ 0.86	$ 0.84
Basic weighted - average common shares outstanding (in shares):	33,087	32,935	33,038	32,876
Effect of dilutive securities (in shares)	562	456	542	475
Diluted weighted - average common shares outstanding (in shares)	33,649	33,391	33,580	33,351
Cash dividends declared per share (in dollars per share)	$ 0.04	$ 0.04	$ 0.12	$ 0.12