INCOME TAXES - Income from Continuing Operations before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
United States	$ (68,895)	$ (73,539)	$ 33,928
Foreign	(11,700)	(3,538)	9,337
Total (loss) income before income taxes	$ (80,595)	$ (77,077)	$ 43,265