Adjusted Quick Ratio under the covenants of the credit facility.

No definition available.

Name:	ment_AdjustedQuickRatio
Namespace Prefix:	ment_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of our cumulative net income added to the dollar limitation under the revolving credit facility, for which we may declare dividends or repurchase our stock.

+ References

No definition available.

+ Details

Name:	ment_AmountAvailableForDividendDistributionPercentOfCumulativeNetIncome
Namespace Prefix:	ment_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Cash and Accounts Receivable Ratio under the covenants of the credit facility.

+ References

No definition available.

+ Details

Name:	ment_CashAndAccountsReceivableRatio
Namespace Prefix:	ment_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

Leverage Ratio under the covenants of the credit facility.

+ References

No definition available.

+ Details

Name:	ment_LeverageRatio
Namespace Prefix:	ment_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount added to the percent of cumulative net income to calculate the limit for which we may declare dividends or purchase our stock under the covenants of the credit facility.

+ References

No definition available.

+ Details

Name:	ment_MaximumAmountAvailableForDividendsAndStockRepurchaseDollarLimit
Namespace Prefix:	ment_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage of Net Current Account Receivable Included in Cash and Account Receivable Ratio under the covenants of the credit facility.

+ References

No definition available.

+ Details

Name:	ment_PercentageOfNetCurrentAccountReceivableIncludedInCashAndAccountReceivableRatio
Namespace Prefix:	ment_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Senior Leverage Ratio under the covenants of the credit facility.

+ References

No definition available.

+ Details

Name:	ment_SeniorLeverageRatio
Namespace Prefix:	ment_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20, 22

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ 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 210.5-02.19(b),22(b))

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

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

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_LineOfCreditFacilityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
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 fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
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Period Type:

Short-Term Borrowings - Additional Information (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended	12 Months Ended
	Jan. 31, 2015	Jan. 31, 2015	Jan. 31, 2014
Line of Credit Facility
Amount outstanding	$ 0us-gaap_LineOfCredit	$ 0us-gaap_LineOfCredit	$ 0us-gaap_LineOfCredit
Revolving Credit Facility
Line of Credit Facility
Termination date for senior, unsecured revolving credit facility	Jan. 09, 2020
Revolving credit facility, maximum borrowing capacity	125,000	125,000
Percentage of net current account receivable included in cash and account receivable ratio		42.00%
Maximum amount available for dividends and stock repurchase dollar limit		$ 50,000
Maximum amount available for dividend distribution and stock repurchase percent of cumulative net income		70.00%
Minimum \| Revolving Credit Facility
Line of Credit Facility
Commitment fee percentage on unused line of credit		0.30%
Adjusted quick ratio		1.00
Cash and accounts receivable ratio		1.25
Minimum \| L I B O R \| Revolving Credit Facility
Line of Credit Facility
Basis spread on variable rate		2.00%
Minimum \| Base Rate \| Revolving Credit Facility
Line of Credit Facility
Basis spread on variable rate		1.00%
Maximum \| Revolving Credit Facility
Line of Credit Facility
Commitment fee percentage on unused line of credit		0.40%
Leverage ratio		2.00
Senior leverage ratio		0.90
Maximum \| L I B O R \| Revolving Credit Facility
Line of Credit Facility
Basis spread on variable rate		2.50%
Maximum \| Base Rate \| Revolving Credit Facility
Line of Credit Facility
Basis spread on variable rate		1.50%