Income taxes - Components of Comprehensive Provision for Income Taxes Allocation (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Comprehensive provision for income taxes allocable to:
Net income	$ (965)	$ (5,576)	$ (6,844)	$ 3,564
Additional paid-in capital	0	0	18	125
Other comprehensive income (loss):
Currency translation	(92)	(1,657)	(906)	(3,560)
Other	6	(18)	(78)	(52)
Total	(947)	(7,032)	(7,307)	756
Defined Benefit Pension Plans
Other comprehensive income (loss):
Pension plans	$ 104	$ 219	$ 503	$ 679