Employee benefit plans - Components of Net Periodic Defined Benefit Cost (Income) (Detail) - Defined Benefit Pension Plans - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 365	$ 450
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
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
Expected return on plan assets	$ (335)	$ (414)
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
Recognized actuarial losses	$ 333	$ 358
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
Total	$ 363	$ 394