Derivative Instruments And Hedging Activities (Narrative) (Details)	12 Months Ended
Mar. 31, 2012 M
Derivative Instruments And Hedging Activities [Abstract]
Hedging forecasted cash flows for operating expenses denominated in foreign currencies managed in months	12
Contract maturing over next months	12

Hedging Forecasted Cash Flows For Operating Expenses Denominated In Foreign Currencies Managed In Months

No definition available.

Name:	ntct_HedgingForecastedCashFlowsForOperatingExpensesDenominatedInForeignCurrenciesManagedInMonths
Namespace Prefix:	ntct_
Data Type:	xbrli:positiveIntegerItemType
Balance Type:	na
Period Type:	duration