Document and Entity Information - shares	9 Months Ended
	Dec. 31, 2018	Jan. 30, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	NETSCOUT SYSTEMS INC
Entity Central Index Key	0001078075
Current Fiscal Year End Date	--03-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Trading Symbol	NTCT
Amendment Flag	false
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		77,831,786