Income taxes - Components of Comprehensive Provision (Benefit) for Income Taxes Allocation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Comprehensive provision (benefit) for income taxes allocable to:
Income tax expense	$ 1,472	$ (23)
Other comprehensive income (loss):
Currency translation	270	1,112
Other		(9)
Total	1,765	1,165
Pension Plan
Other comprehensive income (loss):
Defined benefit pension plans	$ 23	$ 85