CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME
Revenues	$ 366,694	$ 371,084	$ 310,611
Cost of goods sold	258,119	258,500	219,208
Gross profit	108,575	112,584	91,403
Operating costs and expenses:
Selling	15,392	16,536	11,807
General and administrative	38,301	37,688	32,037
Engineering and development	25,487	23,086	19,913
Business development	473	113	762
Amortization of intangible assets	5,928	5,718	3,655
Total operating costs and expenses	85,581	83,141	68,174
Operating income	22,994	29,443	23,229
Other expense, net:
Interest expense	3,716	5,134	2,701
Other expense (income), net	502	468	(153)
Total other expense, net	4,218	5,602	2,548
Income before income taxes	18,776	23,841	20,681
Provision for income taxes	(5,133)	(6,819)	(4,756)
Net income	$ 13,643	$ 17,022	$ 15,925
Basic earnings per share:
Earnings per share	$ 1.44	$ 1.81	$ 1.72
Basic weighted average common shares	9,495	9,398	9,265
Diluted earnings per share:
Earnings per share	$ 1.43	$ 1.80	$ 1.70
Diluted weighted average common shares	9,555	9,461	9,370
Net income	$ 13,643	$ 17,022	$ 15,925
Other comprehensive income:
Foreign currency translation adjustment	8,410	(680)	(3,109)
Change in accumulated income (loss) on derivatives	(1,161)	(711)	238
Pension adjustments	(5)	(622)	(61)
Comprehensive income	$ 20,887	$ 15,009	$ 12,993