ACQUISITION, GOODWILL, AND ACQUIRED INTANGIBLE ASSETS - Narrative (Details) - USD ($) $ in Thousands, shares in Millions		3 Months Ended
	Jul. 02, 2018	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		4 years 8 months 12 days
Goodwill		$ 1,279,897		$ 1,278,380
Cost of revenues		235,121	$ 111,466
Operating Expenses		241,495	89,194
Triangle [Member]
Business Acquisition [Line Items]
Ownership percentage	16.00%
Polycom [Member]
Business Acquisition [Line Items]
Amortization of Intangible Assets		$ 45,300
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		4 years 8 months 1 day
Goodwill	$ 1,264,417
Business Combination, Consideration Transferred	$ 2,200,000
Business Combination, Consideration Transferred, Equity Interests Issued And Issuable, Shares	6.4
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned	$ 500,000
Payments to Acquire Businesses, Gross	$ 1,700,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Deferred Tax And Tax Liabilities		$ 45,200
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Working Capital Adjustment		8,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Other		1,400
Goodwill, Period Increase (Decrease)		$ 54,600
Deferred Revenue Adjustment [Member] | Polycom [Member]
Business Acquisition [Line Items]
Revenues			(36,600)
Acquisition-related Costs [Member] | Polycom [Member]
Business Acquisition [Line Items]
Operating Expenses			19,600
Fair Value Adjustment to Inventory [Member] | Polycom [Member]
Business Acquisition [Line Items]
Cost of revenues			$ 30,400