GOODWILL AND INTANGIBLE ASSETS - Narrative (Details) $ in Thousands	3 Months Ended
	Jun. 30, 2019 USD ($) reporting_unit	Jun. 30, 2018 USD ($)	Mar. 31, 2019 USD ($)
Acquired Finite-Lived Intangible Assets [Line Items]
Number of reporting units | reporting_unit	2
Goodwill	$ 1,717,945		$ 1,715,485
Carrying value of intangible assets	648,997		669,118
Impairment of intangible assets	$ 0	$ 35,871
Weighted average useful life of acquired intangible assets	14 years 7 months 6 days
Developed and core technology
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life of acquired intangible assets	11 years 3 months 18 days
Customer and distributor relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life of acquired intangible assets	15 years 10 months 24 days
Trademarks and trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life of acquired intangible assets	8 years 7 months 6 days
Capitalized software
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life of acquired intangible assets	3 years
Trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	$ 18,600		18,600
Service Assurance
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill	1,200,000		1,200,000
Security
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 555,900		$ 551,100