GOODWILL AND INTANGIBLE ASSETS - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Mar. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Cost	$ 1,106,996	$ 1,091,953
Accumulated Amortization	(573,813)	(528,374)
Net	533,183	563,579
Developed technology
Finite-Lived Intangible Assets [Line Items]
Cost	251,824	249,675
Accumulated Amortization	(203,010)	(191,876)
Net	48,814	57,799
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Cost	775,018	767,366
Accumulated Amortization	(305,680)	(275,361)
Net	469,338	492,005
Distributor relationships and technology licenses
Finite-Lived Intangible Assets [Line Items]
Cost	11,454	6,785
Accumulated Amortization	(7,233)	(6,321)
Net	4,221	464
Definite-lived trademark and trade name
Finite-Lived Intangible Assets [Line Items]
Cost	39,394	39,059
Accumulated Amortization	(28,960)	(26,246)
Net	10,434	12,813
Core technology
Finite-Lived Intangible Assets [Line Items]
Cost	7,192	7,192
Accumulated Amortization	(7,133)	(7,074)
Net	59	118
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	16,461	16,223
Accumulated Amortization	(16,461)	(16,223)
Net	0	0
Capitalized software
Finite-Lived Intangible Assets [Line Items]
Cost	3,317	3,317
Accumulated Amortization	(3,255)	(3,202)
Net	62	115
Other
Finite-Lived Intangible Assets [Line Items]
Cost	1,208	1,208
Accumulated Amortization	(953)	(943)
Net	$ 255	$ 265