Employee benefit obligations - Schedule of Net Funded Status (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Change in Benefit Obligation
Projected benefit obligation at beginning of year	$ 61,355	$ 51,057
Interest cost	$ 646	$ 703
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax
Company service cost	$ 4,887	$ 4,202
Employee contributions	3,551	2,683
Benefits paid	30	2,772
Actuarial loss	10,548	(62)
Projected benefit obligation at end of year	81,017	61,355
Change in Plan Assets
Fair value of plan assets at beginning of year	54,816	43,250
Actual return on plan assets	14,058	2,120
Employer contributions	5,092	3,991
Employee contributions	3,551	2,683
Benefits paid	30	2,772
Fair value of plan assets at end of year	77,547	54,816
Funded Status at End of year
Excess of obligation over assets	3,470	6,539
Change in Accrued Benefit Liability
Accrued benefit liability at beginning of year	(6,539)	(7,807)
Company contributions made during year	5,092	3,991
Net periodic benefit cost for year	(4,806)	(3,308)
Net decrease (increase) in accumulated other comprehensive loss	2,783	585
Accrued benefit liability at end of year	(3,470)	(6,539)
Non-current plan assets	77,547	54,816
Non-current liability	81,017	61,355
Accrued benefit liability at end of year	(3,470)	(6,539)
Projected Benefit Payments
Projected year 1	1,950	1,204
Projected year 2	2,310	1,540
Projected year 3	1,277	1,849
Projected year 4	1,319	966
Projected year 5	2,177	1,748
Projected years 6-10	$ 34,993	$ 24,374