EMPLOYEE BENEFIT PLANS - Net Periodic Pension Cost (Credit) (Details) - U.K. Plan - Pension Plan - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 426	$ 586	$ 867	$ 1,179
Expected return on plan assets	(558)	(600)	(1,135)	(1,207)
Amortization of prior service cost	8	8	16	16
Net periodic pension credit	$ (124)	$ (6)	$ (252)	$ (12)