Employee benefit plans - Components of Net Periodic Defined Benefit Cost (Income) (Detail) - Defined Benefit Pension Plans - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 393	$ 297	$ 1,255	$ 891
Expected return on plan assets	(321)	(392)	(1,087)	(1,176)
Recognized actuarial losses	358	373	1,074	1,119
Total	$ 430	$ 278	$ 1,242	$ 834