REVENUE Deferred Revenue Activity (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020
Movement in Deferred Revenue [Roll Forward]
Deferred revenue at January 1, 2020	$ 97,901
Billings deferred	39,334
Recognition of prior deferred revenue	(51,512)
Deferred revenue at June 30, 2020	85,723
Deferred Revenue Arrangement [Line Items]
Remaining Performance Obligation		$ 56,300
Deferred Revenue	$ 85,723	85,723
Products
Deferred Revenue Arrangement [Line Items]
Remaining Performance Obligation		5,943
Subscription services
Deferred Revenue Arrangement [Line Items]
Remaining Performance Obligation		2,031
Support contracts
Deferred Revenue Arrangement [Line Items]
Remaining Performance Obligation		65,161
Implied PCS
Deferred Revenue Arrangement [Line Items]
Remaining Performance Obligation		9,784
Professional services, training and other
Deferred Revenue Arrangement [Line Items]
Remaining Performance Obligation		$ 2,804