PENSIONS - Reconciliation of Benefit Obligation (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of benefit obligation:
Benefit obligation at January 1	$ 49,943	$ 46,093
Service cost	155	162	$ 250
Interest cost	1,271	1,740	1,687
Actuarial loss	5,458	4,581
Foreign currency exchange rate changes	372	433
Benefit payments	(3,077)	(3,066)
Benefit obligation at December 31	$ 54,122	$ 49,943	$ 46,093

Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan.

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- Definition

Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

+ References

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- Definition

Amount of payment to participant of defined benefit plan which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Amount of foreign currency translation gain (loss) which (increases) decreases benefit obligation of defined benefit plan.

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- Definition

Amount of cost recognized for passage of time related to defined benefit plan.

+ References

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- Definition

Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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