Income taxes - Components of Comprehensive Provision (Benefit) for Income Taxes Allocation (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Comprehensive provision (benefit) for income taxes allocable to:
Net income (loss)	$ 8,508	$ (965)	$ 10,798	$ (6,844)
Additional paid-in capital	0	0	8	18
Other comprehensive income (loss):
Currency translation	404	(92)	(792)	(906)
Other	(14)	6	(33)	(78)
Total	8,997	(947)	10,282	(7,307)
Defined Benefit Pension Plans
Other comprehensive income (loss):
Pension plans	$ 99	$ 104	$ 301	$ 503