Employee Benefit Plans - Valuation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Valuation
Maximum percentage of unrecognized gains (losses) for amortization	10.00%
Amortization period for gains (losses) of defined benefit plans	9 years
Fair value of plan assets	$ 52,081	$ 45,694	$ 89,972
Weighted-average assumptions used to determine net periodic benefit cost:
Expected asset return	5.79%
U.K. Pension Plan
Valuation
Historical performance period	10 years
Weighted-average assumptions used to determine benefit obligations:
Discount rate	4.80%	5.00%
Weighted-average assumptions used to determine net periodic benefit cost:
Discount rate	5.00%	1.80%
Expected asset return	5.87%	3.45%
U.K. Pension Plan | Minimum
Valuation
Historical performance period	15 years
U.K. Pension Plan | Maximum
Valuation
Historical performance period	20 years
Asterion Pension Plan
Weighted-average assumptions used to determine benefit obligations:
Discount rate	3.16%	3.80%
Weighted-average assumptions used to determine net periodic benefit cost:
Discount rate	3.16%	3.80%
Expected asset return	3.16%	3.80%
Norway Pension Plan
Weighted-average assumptions used to determine benefit obligations:
Discount rate	3.10%	3.00%
Rate of compensation increase	3.50%	3.50%
Weighted-average assumptions used to determine net periodic benefit cost:
Discount rate	3.10%	3.00%
Expected asset return	4.45%	4.15%
Rate of compensation increase	3.50%	3.50%
German Pension Plan
Valuation
Fair value of plan assets	$ 0
Weighted-average assumptions used to determine benefit obligations:
Discount rate	3.16%	3.80%
Weighted-average assumptions used to determine net periodic benefit cost:
Discount rate	3.16%	3.80%
German Pension Plan | Minimum
Valuation
Historical performance period	10 years
German Pension Plan | Maximum
Valuation
Historical performance period	20 years
Unfunded Plan | German Pension Plan
Valuation
Fair value of plan assets	$ 0