Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenue	$ 136,718	$ 110,643
Cost of sales	102,594	86,384
Gross profit	34,124	24,259
Research and development costs	5,009	4,986
Selling, general and administrative expenses	21,026	20,995
Gain on sale of property	0	(6,175)
Income from operations	8,089	4,453
Interest expense	(688)	(801)
Other (expense) income, net	(773)	546
Earnings before provision for income taxes	6,628	4,198
Provision for income taxes	1,564	999
Net earnings available to common stockholders	5,064	3,199
Common Class A [Member]
Net earnings available to common stockholders	$ 821	$ 522
Net earnings per common share:
Common shares - basic and diluted (in dollars per share)	$ 0.38	$ 0.24
Weighted-average number of shares outstanding:
Common shares - basic and diluted (in shares)	2,145	2,145
Common Class B [Member]
Net earnings available to common stockholders	$ 4,243	$ 2,677
Net earnings per common share:
Common shares - basic and diluted (in dollars per share)	$ 0.41	$ 0.26
Weighted-average number of shares outstanding:
Common shares - basic and diluted (in shares)	10,374	10,203