Document and Entity Information - shares	9 Months Ended
	Dec. 31, 2015	Jan. 27, 2016
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, 2015
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	Q3
Trading Symbol	NTCT
Amendment Flag	false
Entity Common Stock, Shares Outstanding		98,570,412