Employee benefit plans - Components of Net Periodic Defined Benefit Cost (Income) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 1,619	$ 1,138	$ 947
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Comprehensive Income Loss Amortization Adjustment From A O C I Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax	Other Comprehensive Income Loss Amortization Adjustment From A O C I Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax	Other Comprehensive Income Loss Amortization Adjustment From A O C I Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax
Plan settlement	$ (4,911)	$ (104)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Comprehensive Income Loss Amortization Adjustment From A O C I Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax	Other Comprehensive Income Loss Amortization Adjustment From A O C I Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax	Other Comprehensive Income Loss Amortization Adjustment From A O C I Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax
Expected return on plan assets	$ (1,452)	$ (1,552)	$ (1,603)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Comprehensive Income Loss Amortization Adjustment From A O C I Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax	Other Comprehensive Income Loss Amortization Adjustment From A O C I Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax	Other Comprehensive Income Loss Amortization Adjustment From A O C I Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax
Recognized actuarial losses	$ 1,391	$ 1,664	$ 1,562
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Comprehensive Income Loss Amortization Adjustment From A O C I Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax	Other Comprehensive Income Loss Amortization Adjustment From A O C I Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax	Other Comprehensive Income Loss Amortization Adjustment From A O C I Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax
Total	$ 6,469	$ 1,354	$ 906
Defined Benefit Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 1,619	$ 1,138