Employee Benefit Plans - Actuarial assumptions used to determine benefit obligation and net periodic benefit costs (Details)	12 Months Ended
	Dec. 31, 2025
U.K. Pension Plan
Weighted-average assumptions used to determine net periodic benefit costs:
Expected asset return	6.82%
Pension Plan | U.K. Pension Plan
Weighted-average assumptions used to determine benefit obligations:
Discount rate	5.60%
Weighted-average assumptions used to determine net periodic benefit costs:
Discount rate	5.60%
Expected asset return	6.82%
Pension Plan | German Pension Plan
Weighted-average assumptions used to determine benefit obligations:
Discount rate	3.90%
Weighted-average assumptions used to determine net periodic benefit costs:
Discount rate	3.90%
Pension Plan | Norway Pension Plan
Weighted-average assumptions used to determine benefit obligations:
Discount rate	3.90%
Rate of compensation increase	4.00%
Weighted-average assumptions used to determine net periodic benefit costs:
Discount rate	3.90%
Expected asset return	5.10%
Rate of compensation increase	4.00%
Pension Plan | Asterion Pension Plan
Weighted-average assumptions used to determine benefit obligations:
Discount rate	3.90%
Weighted-average assumptions used to determine net periodic benefit costs:
Discount rate	3.90%
Expected asset return	3.90%