RESTRUCTURING AND FACILITIES CONSOLIDATION INITIATIVES - Accrual Activity for Severance and Related Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Restructuring Reserve [Roll Forward]
Initiatives charged to expense	$ 2,075	$ 4,932
Facilities
Restructuring Reserve [Roll Forward]
Balance at the beginning of the period	900
Balance at the end of the period	900
2019 Restructuring Initiative
Restructuring Reserve [Roll Forward]
Balance at the beginning of the period	3,101
Initiatives charged to expense	959
Reclassify accelerated amortization to operating lease liabilities	(70)
Cash payments	(1,525)
Balance at the end of the period	2,465
2019 Restructuring Initiative | Severance
Restructuring Reserve [Roll Forward]
Balance at the beginning of the period	2,110
Initiatives charged to expense	655
Reclassify accelerated amortization to operating lease liabilities	0
Cash payments	(1,253)
Balance at the end of the period	1,512
2019 Restructuring Initiative | Facilities
Restructuring Reserve [Roll Forward]
Balance at the beginning of the period	991
Initiatives charged to expense	304
Reclassify accelerated amortization to operating lease liabilities	(70)
Cash payments	(272)
Balance at the end of the period	$ 953