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

Defined Contribution Plan Vesting Term

No definition available.

Name:	ment_DefinedContributionPlanVestingTerm
Namespace Prefix:	ment_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

[Line Items] for Disclosure Matching Contributions To Savings Plans [Table]

No definition available.

Name:	ment_DisclosureMatchingContributionsToSavingsPlansLineItems
Namespace Prefix:	ment_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The amount of the cost recognized during the period for defined contribution plans.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

Name:	us-gaap_DefinedContributionPlanCostRecognized
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

No definition available.

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

Percentage of employer's matching contributions to a defined contribution plan that vests in a given year.

No definition available.