Pension and other postretirement benefits - Summarized information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning of year	$ 474,674	$ 501,347
Service cost	1,346	1,467	$ 1,416
Interest cost	10,776	9,272	12,827
Actuarial (gain) loss	(104,558)	(13,567)
Currency translation	(3,030)	(1,726)
Benefits paid	(21,472)	(21,138)
Medicare Part D reimbursement	0	0
Administrative costs	(979)	(981)
Projected benefit obligation, end of year	356,757	474,674	501,347
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of year	469,793	457,626
Actual return on plan assets	(89,506)	22,124
Contributions	1,464	12,159
Benefits paid	(21,472)	(21,138)
Administrative costs	(979)	(981)
Currency translation	(2,030)	3
Fair value of plan assets, end of year	357,270	469,793	457,626
Funded status, end of year	513	(4,881)
Other Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning of year	26,804	31,921
Service cost	0	0	0
Interest cost	477	418	902
Actuarial (gain) loss	(6,223)	(2,288)
Currency translation	0	0
Benefits paid	(2,491)	(3,303)
Medicare Part D reimbursement	53	56
Administrative costs	0	0
Projected benefit obligation, end of year	18,620	26,804	$ 31,921
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Administrative costs	0	0
Funded status, end of year	$ (18,620)	$ (26,804)