Pension and other postretirement benefits - Summarized information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning of year	$ 356,757	$ 474,674
Service cost	1,435	1,346	$ 1,467
Interest cost	17,297	10,776	9,272
Actuarial loss (gain)	11,557	(104,558)
Currency translation	1,067	(3,030)
Benefits paid	(21,208)	(21,472)
Liability gain due to settlement	(15,272)	0
Medicare Part D reimbursement	0	0
Plan amendments	0	0
Settlements	73,932	0
Administrative costs	(2,304)	(979)
Projected benefit obligation, end of year	275,397	356,757	474,674
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of year	357,270	469,793
Actual return on plan assets	23,740	(89,506)
Contributions	1,276	1,464
Benefits paid	(95,139)	(21,472)
Administrative costs	(2,304)	(979)
Currency translation	670	(2,030)
Fair value of plan assets, end of year	285,513	357,270	469,793
Funded status, end of year	10,116	513
Other Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning of year	18,620	26,804
Service cost	0	0	0
Interest cost	824	477	418
Actuarial loss (gain)	(508)	(6,223)
Currency translation	0	0
Benefits paid	(1,910)	(2,491)
Liability gain due to settlement	0	0
Medicare Part D reimbursement	(3)	53
Plan amendments	(7,488)	0
Settlements	0	0
Administrative costs	0	0
Projected benefit obligation, end of year	9,535	18,620	$ 26,804
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Administrative costs	0	0
Funded status, end of year	$ (9,535)	$ (18,620)