Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Net sales	$ 158,682	$ 177,739	$ 499,803	$ 485,030
Cost of sales	103,217	126,205	335,137	354,084
Gross profit	55,465	51,534	164,666	130,946
Research and development costs	5,292	4,877	16,521	14,381
Selling, general and administrative expenses	23,717	22,223	74,149	67,216
Restructuring charges	2,091	3,969	6,306	4,000
Gains on sale of properties	(147)	(1,596)	(3,819)	(1,596)
Income from operations	24,512	22,061	71,509	46,945
Gain on sale of Czech Republic business	(135)	0	980	0
Interest expense	(512)	(944)	(2,402)	(2,411)
Other expense, net	(96)	(429)	(286)	(2,926)
Earnings before provision for income taxes	23,769	20,688	69,801	41,608
Provision for income taxes	4,321	4,140	8,006	2,959
Net earnings available to common stockholders	19,448	16,548	61,795	38,649
Common Class A [Member]
Net earnings available to common stockholders	$ 3,117	$ 2,715	$ 9,907	$ 6,327
Net earnings per common share:
Net earnings per common share - basic and diluted (in dollars per share)	$ 1.46	$ 1.27	$ 4.63	$ 2.95
Weighted-average number of shares outstanding:
Weighted-average number of shares outstanding - basic and diluted (in shares)	2,142	2,142	2,142	2,144
Common Class B [Member]
Net earnings available to common stockholders	$ 16,331	$ 13,833	$ 51,888	$ 32,322
Net earnings per common share:
Net earnings per common share - basic and diluted (in dollars per share)	$ 1.54	$ 1.34	$ 4.88	$ 3.12
Weighted-average number of shares outstanding:
Weighted-average number of shares outstanding - basic and diluted (in shares)	10,636	10,340	10,636	10,358