Segment information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2025 USD ($) segment	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Segment information
Number of operating segments | segment	1
Number of reportable segments | segment	1
Revenues	$ 246,614	$ 237,118	$ 289,025
Less:
Interest (income) expense - net	(2,532)	(476)	8,352
Income taxes	6,024	7,639	17,573
Other income	(1,600)	(2,250)
Net income	$ 16,667	$ 24,388	$ 52,247
Other operating expenses, description	1Other operating expenses include miscellaneous, individually insignificant operating expenses. The Company’s CODM reviews these items in aggregate.	1Other operating expenses include miscellaneous, individually insignificant operating expenses. The Company’s CODM reviews these items in aggregate.	1Other operating expenses include miscellaneous, individually insignificant operating expenses. The Company’s CODM reviews these items in aggregate.
Single Reporting Segment
Segment information
Revenues	$ 246,614	$ 237,118	$ 289,025
Less:
Cost of materials and plant overhead	169,577	157,508	163,701
Payroll expense and benefits	37,748	31,625	28,186
Interest (income) expense - net	(2,532)	(476)	8,352
Depreciation and amortization	5,991	6,387	5,782
Professional fees	6,751	6,720	4,423
Other operating expenses	7,988	5,577	8,761
Income taxes	6,024	7,639	17,573
Other income	(1,600)	(2,250)
Net income	$ 16,667	$ 24,388	$ 52,247