Comprehensive Income - Reclassification adjustments out of accumulated other comprehensive loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Reclassification adjustments out of accumulated other comprehensive loss
Other expense, net	$ (59)	$ (143)	$ (186)	$ (238)
Earnings before provision for income taxes	4,618	7,482	12,155	16,543
Provision for income taxes	2,362	1,875	4,356	4,286
Net Income (Loss)	2,256	5,607	7,799	12,257
Amortization of defined benefit pension items | Reclassification out of Accumulated Other Comprehensive Income
Reclassification adjustments out of accumulated other comprehensive loss
Earnings before provision for income taxes	55	99	110	198
Provision for income taxes	(14)	(26)	(28)	(52)
Net Income (Loss)	41	73	82	146
Prior service cost | Reclassification out of Accumulated Other Comprehensive Income
Reclassification adjustments out of accumulated other comprehensive loss
Other expense, net	5	5	10	10
Actuarial losses | Reclassification out of Accumulated Other Comprehensive Income
Reclassification adjustments out of accumulated other comprehensive loss
Other expense, net	$ 50	$ 94	$ 100	$ 188