EMPLOYEE BENEFIT PLANS - Changes in Benefit Obligation and Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Projected benefit obligation:
Beginning of year	$ 96,875	$ 89,206
Service cost	77	90	$ 79
Interest cost	2,303	2,438	2,504
Actuarial (gain) loss	(4,347)	890
Benefits paid	(4,539)	(4,187)
Prior service cost	669	0	0
Disposal of Norwegian Plan	(1,075)	0
Foreign currency translation adjustment and other	(5,404)	8,438
End of year	84,559	96,875	89,206
Fair value of plan assets:
Beginning of year	81,899	67,967
Actual gain (loss) on plan assets	(462)	7,383
Employer contributions	2,404	4,350
Benefits paid	(4,539)	(4,187)
Disposal of Norwegian Plan	(983)	0
Foreign currency translation adjustment and other	(4,700)	6,386
End of year	73,619	81,899	$ 67,967
Excess projected obligation under (over) fair value of plan assets at end of year	(10,940)	(14,976)
Amounts recognized in accumulated other comprehensive loss:
Net actuarial loss	(7,190)	(7,221)
Prior service cost	(669)	0
Total	$ 7,859	$ 7,221