GOODWILL AND INTANGIBLE ASSETS - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Mar. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Cost	$ 1,090,547	$ 1,090,656
Accumulated Amortization	(484,348)	(440,138)
Net	606,199	650,518
Developed technology
Finite-Lived Intangible Assets [Line Items]
Cost	245,601	242,259
Accumulated Amortization	(180,008)	(168,289)
Net	65,593	73,970
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Cost	769,809	772,969
Accumulated Amortization	(246,711)	(218,043)
Net	523,098	554,926
Distributor relationships and technology licenses
Finite-Lived Intangible Assets [Line Items]
Cost	6,827	6,882
Accumulated Amortization	(5,814)	(5,237)
Net	1,013	1,645
Definite-lived trademark and trade name
Finite-Lived Intangible Assets [Line Items]
Cost	39,166	39,304
Accumulated Amortization	(23,414)	(20,586)
Net	15,752	18,718
Core technology
Finite-Lived Intangible Assets [Line Items]
Cost	7,192	7,192
Accumulated Amortization	(6,959)	(6,845)
Net	233	347
Net beneficial leases
Finite-Lived Intangible Assets [Line Items]
Cost	336	336
Accumulated Amortization	(336)	(336)
Net	0	0
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Cost	292	292
Accumulated Amortization	(292)	(292)
Net	0	0
Leasehold interest
Finite-Lived Intangible Assets [Line Items]
Cost	500	500
Accumulated Amortization	(500)	(500)
Net	0	0
Backlog
Finite-Lived Intangible Assets [Line Items]
Cost	16,299	16,397
Accumulated Amortization	(16,299)	(16,397)
Net	0	0
Capitalized software
Finite-Lived Intangible Assets [Line Items]
Cost	3,317	3,317
Accumulated Amortization	(3,083)	(2,690)
Net	234	627
Other
Finite-Lived Intangible Assets [Line Items]
Cost	1,208	1,208
Accumulated Amortization	(932)	(923)
Net	$ 276	$ 285