Trade accounts receivable - net - Reserves for doubtful accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Trade accounts receivable - net
Beginning Balance	$ 1,927	$ 1,584
Net additions charged to Operations	659	474	$ 44
Deductions and Other	(592)	(131)
Ending Balance	$ 1,994	$ 1,927	$ 1,584