Document and Entity Information - USD ($)	12 Months Ended
	Mar. 31, 2019	May 13, 2019	Sep. 30, 2018
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, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		77,462,629
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Public Float			$ 1,886,903,665