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This represents new contingent consideration arising from a contingency assumed in a business combination during the reporting period.

No definition available.

Name:	ment_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilitiesAssumedInBusinessCombination
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The change in the estimated liability for contingent consideration resulting in a gain or loss in the statement of operations during the reporting period.

No definition available.

Name:	ment_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValueChangeInEstimate
Namespace Prefix:	ment_
Data Type:	xbrli:monetaryItemType
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- Details

Name:	us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationAbstract
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Data Type:	xbrli:stringItemType
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- Details

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Data Type:	xbrli:stringItemType
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Amount of increase (decrease) of liabilities measured at fair value on a recurring basis using unobservable inputs (level 3) which have taken place during the period. Such increase (decrease) may be comprised of changes in fair value (gains or losses) whether realized or unrealized that have been included in earnings, changed net asset value, or other comprehensive income (a separate component of shareholders' equity); purchases, sales, issues, or settlements of assets; and net transfers in to or out of this category within the fair value hierarchy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-Subparagraph c(1), c(2), c(3)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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Settlements that have taken place during the period in relation to liabilities measured at fair value and categorized within Level 3 of the fair value hierarchy.

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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This element represents a liability measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances.