Employee benefit plans - Components of Net Periodic Defined Benefit Cost (Income) (Detail) - Defined Benefit Pension Plans - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 297	$ 279	$ 594	$ 432
Expected return on plan assets	(392)	(398)	(784)	(796)
Recognized actuarial losses	373	376	746	752
Total	$ 278	$ 257	$ 556	$ 388