Income taxes - Components of Comprehensive Provision for Income Taxes Allocation (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Comprehensive provision for income taxes allocable to:
Net income	$ (7,300)	$ 6,435	$ (5,879)	$ 9,140
Additional paid-in capital	110	9	18	125
Other comprehensive income (loss):
Currency translation	(371)	(2,323)	(814)	(1,903)
Other	(50)	(17)	(84)	(35)
Total	(7,316)	4,332	(6,360)	7,787
Defined Benefit Pension Plans
Other comprehensive income (loss):
Pension plans	$ 295	$ 228	$ 399	$ 460