Consolidated Statements of Earnings - Unaudited - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Net sales	$ 120,684	$ 118,021	$ 238,308	$ 231,551
Cost of goods sold	79,480	76,208	156,490	151,305
Gross Margin	41,204	41,813	81,818	80,246
Selling, general and administrative expenses	17,036	19,621	34,597	36,993
Research and development expenses	6,257	6,476	13,048	12,983
Restructuring charges	911	1,172	2,995	2,367
Gain (Loss) on Disposition of Property Plant Equipment	83	0	122	0
Operating earnings	17,083	14,544	31,300	27,903
Other income (expense):
Interest expense	(467)	(571)	(933)	(1,112)
Interest income	440	472	872	954
Other expense, net	(1,107)	(2,874)	(1,010)	(870)
Total other expense, net	(1,134)	(2,973)	(1,071)	(1,028)
Earnings before income taxes	15,949	11,571	30,229	26,875
Income tax expense	4,006	4,362	6,867	8,118
Net earnings	$ 11,943	$ 7,209	$ 23,362	$ 18,757
Earnings per share:
Basic (in dollars per share)	$ 0.36	$ 0.22	$ 0.71	$ 0.57
Diluted (in dollars per share)	$ 0.36	$ 0.21	$ 0.70	$ 0.56
Basic weighted - average common shares outstanding (in shares):	32,799	33,051	32,803	33,014
Effect of dilutive securities (in shares)	406	513	422	513
Diluted weighted - average common shares outstanding (in shares)	33,205	33,564	33,225	33,527
Cash dividends declared per share (in dollars per share)	$ 0.04	$ 0.04	$ 0.08	$ 0.08