Leverage Ratio

No definition available.

Name:	ntct_LeverageRatio
Namespace Prefix:	ntct_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Line of credit facility increase in amount term

+ References

No definition available.

+ Details

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

- Definition

Line of credit facility maturity period

+ References

No definition available.

+ Details

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

- Definition

Line of credit facility withdrawal for repayments of debt

+ References

No definition available.

+ Details

Name:	ntct_LineOfCreditFacilityWithdrawalForRepaymentsOfDebt
Namespace Prefix:	ntct_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage of foreign subsidiaries capital stock to be used for repayment of line of credit

+ References

No definition available.

+ Details

Name:	ntct_PercentageOfForeignSubsidiariesCapitalStockToBeUsedForRepaymentOfLineOfCredit
Namespace Prefix:	ntct_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percent Change Of Terms with Certain Syndicate Lenders With The New Credit Agreement

+ References

No definition available.

+ Details

Name:	ntct_PercentChangeOfTermsWithCertainSyndicateLendersWithNewCreditAgreement
Namespace Prefix:	ntct_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Spread Over Interest Rate

+ References

No definition available.

+ Details

Name:	ntct_SpreadOverInterestRate
Namespace Prefix:	ntct_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The average effective interest rate during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateDuringPeriod
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

For an unclassified balance sheet, the amount as of the balance sheet date of capitalized costs associated with the issuance of debt instruments (for example, legal, accounting, underwriting, printing, and registration costs) that will be charged against earnings over the life of the debt instruments to which such costs pertain. Such amount is before the consideration of accumulated amortization.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 21

-Paragraph 16

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28555-108399

+ Details

Name:	us-gaap_DeferredFinanceCostsGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount represents the difference between the fair value of the payments made and the carrying amount of the debt at the time of its extinguishment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 50

-Section 40

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6850294&loc=d3e12355-112629

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 26

-Paragraph 20, 21

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 50

-Section 40

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6850294&loc=d3e12317-112629

+ Details

Name:	us-gaap_GainsLossesOnExtinguishmentOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount borrowed under the credit facility as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

Name:	us-gaap_LineOfCreditFacilityAmountOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Reflects when the credit facility terminates, which may be presented in a variety of ways (year, month and year, day, month and year, quarter).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationDate
Namespace Prefix:	us-gaap_
Data Type:	us-types:dateStringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.17)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_UnamortizedDebtIssuanceExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Long-Term Debt (Details) (USD $)	0 Months Ended	12 Months Ended
Long-Term Debt (Details) (USD $)	Nov. 22, 2011 D	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Debt Instrument [Line Items]
Revolving credit facility outstanding amount	$ 250,000,000	$ 62,000,000
Increase in revolving credit facility outstanding amount	300,000,000
Term for increase in revolving credit facility before maturity date, days	90
Line of credit facility period (in years)		5
Line of credit facility, maturity		November 21, 2016
Gain (loss) on early extinguishment of debt		(690,000)	0	0
Leverage ratio		1.00
Percentage of capital stock of foreign subsidiaries used as guarantee		65.00%
Capitalized debt issuance costs		1,100,000
Unamortized debt included in other assets		1,000,000
Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio		2.50
Minimum [Member]
Debt Instrument [Line Items]
Leverage ratio		1.00
Percent change of terms with certain syndicate lenders with the new credit agreement		10.00%
2007 Facility [Member]
Debt Instrument [Line Items]
Withdrawal for repayment of existing debt	62,000,000
Gain (loss) on early extinguishment of debt		(690,000)
Term Loan [Member]
Debt Instrument [Line Items]
Interest rate at period end		1.50%
Swing Line Loan Sub-Facility [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Revolving credit facility outstanding amount	10,000,000
Letter Of Credit Sub-Facility [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Revolving credit facility outstanding amount	$ 10,000,000
Federal Funds Effective Rate [Member]
Debt Instrument [Line Items]
Interest rate in excess of effective rate		0.50%
LIBOR [Member]
Debt Instrument [Line Items]
Margin over applicable interest rate (basis points)		100
Base Rate Loans [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Margin over applicable interest rate (basis points)		100
Base Rate Loans [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Margin over applicable interest rate (basis points)		25
Eurodollar Rate Loans [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Margin over applicable interest rate (basis points)		200
Eurodollar Rate Loans [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Margin over applicable interest rate (basis points)		125