REVENUE Deferred Revenue Activity (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020
Movement in Deferred Revenue [Roll Forward]
Deferred revenue at January 1, 2020	$ 97,901
Billings deferred	47,723
Recognition of prior deferred revenue	(64,460)
Deferred revenue at September 30, 2020	81,164
Deferred Revenue Arrangement [Line Items]
Remaining Performance Obligation		$ 53,700
Deferred Revenue	$ 81,164	81,164
Products
Deferred Revenue Arrangement [Line Items]
Remaining Performance Obligation		5,133
Subscription services
Deferred Revenue Arrangement [Line Items]
Remaining Performance Obligation		3,320
Support contracts
Deferred Revenue Arrangement [Line Items]
Remaining Performance Obligation		61,596
Implied PCS
Deferred Revenue Arrangement [Line Items]
Remaining Performance Obligation		8,860
Professional services, training and other
Deferred Revenue Arrangement [Line Items]
Remaining Performance Obligation		$ 2,255