INCOME TAXES - Components of Income Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income before income taxes and non-controlling interests [Line Items]
Domestic - Luxembourg	$ (50,821)	$ 8,919	$ (22,513)
Total	(57,705)	12,439	1,399
Foreign - U.S.
Income before income taxes and non-controlling interests [Line Items]
Foreign - U.S. and Non-U.S.	(13,243)	(12,602)	8,398
Foreign - non-U.S.
Income before income taxes and non-controlling interests [Line Items]
Foreign - U.S. and Non-U.S.	$ 6,359	$ 16,122	$ 15,514