CONDENSED CONSOLIDATED STATEMENTS OF EARNINGS - UNAUDITED - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Net sales	$ 113,777	$ 115,651	$ 301,049	$ 353,959
Cost of goods sold	76,871	78,594	204,677	235,084
Gross Margin	36,906	37,057	96,372	118,875
Selling, general and administrative expenses	16,883	17,774	48,310	52,371
Research and development expenses	5,723	6,806	18,653	19,854
Restructuring charges	1,041	2,342	1,416	5,337
Loss (gain) on sale of assets	0	11	0	(111)
Operating earnings	13,259	10,124	27,993	41,424
Other (expense) income:
Interest expense	(857)	(812)	(2,617)	(1,745)
Interest income	217	524	852	1,396
Other income (expense), net	1,617	(2,636)	(109)	(3,646)
Total other income (expense), net	977	(2,924)	(1,874)	(3,995)
Earnings before income taxes	14,236	7,200	26,119	37,429
Income tax expense	3,163	4,478	6,381	11,345
Net earnings	$ 11,073	$ 2,722	$ 19,738	$ 26,084
Earnings per share:
Basic	$ 0.34	$ 0.08	$ 0.61	$ 0.80
Diluted	$ 0.34	$ 0.08	$ 0.61	$ 0.79
Basic weighted – average common shares outstanding:	32,268	32,642	32,331	32,748
Effect of dilutive securities	241	425	270	417
Diluted weighted – average common shares outstanding:	32,509	33,067	32,601	33,165
Cash dividends declared per share	$ 0.04	$ 0.04	$ 0.12	$ 0.12