EMPLOYEE BENEFIT PLANS - Changes in Benefit Obligation and Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Projected benefit obligation:
Beginning of year	$ 84,559	$ 96,875
Service cost	0	77	$ 90
Interest cost	2,323	2,303	2,438
Actuarial (gain) loss	8,425	(4,347)
Benefits paid	(6,050)	(4,539)
Prior service cost	0	669	0
Disposal of Norwegian Plan	0	(1,075)
Foreign currency translation adjustment and other	3,150	(5,404)
End of year	92,407	84,559	96,875
Fair value of plan assets:
Beginning of year	73,619	81,899
Actual gain (loss) on plan assets	10,393	(462)
Employer contributions	2,295	2,404
Benefits paid	(6,050)	(4,539)
Disposal of Norwegian Plan	0	(983)
Foreign currency translation adjustment and other	2,829	(4,700)
End of year	83,086	73,619	$ 81,899
Excess projected obligation under (over) fair value of plan assets at end of year	(9,321)	(10,940)
Amounts recognized in accumulated other comprehensive loss:
Net actuarial loss	(7,365)	(7,190)
Prior service cost	(656)	(669)
Total	$ (8,021)	$ (7,859)