Document and Entity Information - USD ($)	12 Months Ended
	Mar. 31, 2017	May 12, 2017	Sep. 30, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	NETSCOUT SYSTEMS INC
Trading Symbol	NTCT
Entity Central Index Key	0001078075
Current Fiscal Year End Date	--03-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Mar. 31, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		91,720,938
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 2,597,526,506