REVENUE FROM CONTRACTS WITH CUSTOMERS (Balance Sheet) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Apr. 01, 2018	Mar. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net	$ 534,633	$ 301,589	$ 247,649
Software development costs and licenses	36,912	22,188	33,284
Deferred cost of goods sold	20,957	27,984	117,851
Prepaid expenses and other	162,647	167,074	133,454
Deferred cost of goods sold, net of current portion	489	1,032	26,719
Other assets	80,810	108,317	56,887
Accrued expenses and other current liabilities	853,467	984,426	914,748
Deferred revenue	559,024	547,008	777,152
Non-current deferred revenue	15,407	19,133	355,589
Other long-term liabilities	205,554	192,621	158,285
Retained earnings	640,849	543,789	73,516
Accumulated other comprehensive loss	(37,199)	$ (11,079)	$ (15,732)
Amounts without adoption of New Revenue Accounting Standard
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net	488,622
Software development costs and licenses	50,027
Deferred cost of goods sold	116,211
Prepaid expenses and other	98,421
Deferred cost of goods sold, net of current portion	10,837
Other assets	64,931
Accrued expenses and other current liabilities	837,242
Deferred revenue	924,793
Non-current deferred revenue	213,397
Other long-term liabilities	83,459
Retained earnings	207,382
Accumulated other comprehensive loss	(36,572)
Increase (decrease) due to adoption of New Revenue Accounting Standard | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net	46,011
Software development costs and licenses	(13,115)
Deferred cost of goods sold	(95,254)
Prepaid expenses and other	64,226
Deferred cost of goods sold, net of current portion	(10,348)
Other assets	15,879
Accrued expenses and other current liabilities	16,225
Deferred revenue	(365,769)
Non-current deferred revenue	(197,990)
Other long-term liabilities	122,095
Retained earnings	433,467
Accumulated other comprehensive loss	$ (627)