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, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 297	$ 279	$ 891	$ 711
Expected return on plan assets	(392)	(398)	(1,176)	(1,194)
Recognized actuarial losses	373	376	1,119	1,128
Total	$ 278	$ 257	$ 834	$ 645