RESTRUCTURING - Restructuring Reserve (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 11,793	$ 4,511
Costs paid or otherwise settled	(10,564)	(2,607)
Restructuring reserve	3,133	1,904
Facility-related costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	10,188	1,373
Costs paid or otherwise settled	(8,560)	(138)
Restructuring reserve	2,863	1,235
Personnel-related costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	339	1,836
Costs paid or otherwise settled	(695)	(1,326)
Restructuring reserve	154	510
Other costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,266	1,302
Costs paid or otherwise settled	(1,309)	(1,143)
Restructuring reserve	$ 116	$ 159