Name:	mgr_EBPNoteReceivableFromParticipantAccountMaximumSecuredAmountToTotalAccountPercentage
Namespace Prefix:	mgr_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	duration

The percentage of employer contribution vesting schedule less than three years of service.

No definition available.

Name:	mgr_EmployeeBenefitPlanEmployerContributionVestingScheduleLessThanThreeYearsOfServicePercentage
Namespace Prefix:	mgr_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of employer contribution vesting schedule three years of service.

No definition available.

Name:	mgr_EmployeeBenefitPlanEmployerContributionVestingScheduleThreeYearsOfServicePercentage
Namespace Prefix:	mgr_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	duration

Amount of replacement suspense account.

No definition available.

Name:	mgr_EmployeeBenefitPlanEmployerReplacementSuspenseAccount
Namespace Prefix:	mgr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount of employee benefit plan replacement suspense account was used to fund employer discretionary contributions.

No definition available.

Name:	mgr_EmployeeBenefitPlanEmployerReplacementSuspenseAccountUsed
Namespace Prefix:	mgr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The minimum age participants may withdraw amounts due to hardship.

No definition available.

Name:	mgr_EmployeeBenefitPlanMinimumAgeParticipantsMayWithdrawAmountsDueToHardship
Namespace Prefix:	mgr_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

Period of repayment of loan, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

No definition available.

Name:	mgr_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMaximumBorrowingTerm
Namespace Prefix:	mgr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Period of repayment of loan, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

No definition available.

Name:	mgr_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMinimumBorrowingTerm
Namespace Prefix:	mgr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Period of repayment of loan, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

No definition available.

Name:	mgr_EmployeeBenefitPlanNoteReceivableFromParticipantPrincipalResidenceMaximumBorrowingTerm
Namespace Prefix:	mgr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Maximum percentage of participants contributions that may be reallocated

No definition available.

Name:	mgr_EmployeeBenefitPlanParticipantMaximumContributionsThatMayBeReallocatedPercentage
Namespace Prefix:	mgr_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	instant

The age at which participants become eligible for contributions under employee benefit plan.

No definition available.

Name:	mgr_EmployeeBenefitPlanParticipantMinimumAgeEligibleToMakeCatchUpContributions
Namespace Prefix:	mgr_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

Number of service days in employee stock purchase, saving, or similar plan (employee benefit plan (EBP).

No definition available.

Name:	mgr_EmployeeBenefitPlanParticipantMinimumPeriodOfServiceToBeEligibleToParticipateInPlan
Namespace Prefix:	mgr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Amount of participant vested account balance.

No definition available.

Name:	mgr_EmployeeBenefitPlanParticipantVestedAccountBalance
Namespace Prefix:	mgr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Period of repayment of loan, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

No definition available.

Name:	mgr_EmployeeBenefitPlanVestingTerm
Namespace Prefix:	mgr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Percentage points added to the reference rate to compute the variable rate on the notes receivable from participants.

No definition available.

Name:	mgr_NotesReceivableFromParticipantsBasisSpreadOnVariableRate
Namespace Prefix:	mgr_
Data Type:	dtr:percentItemType
Balance Type:	na
Period Type:	duration

Amount of net asset available for benefit transferred to (from) employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) from (to) external plan.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 962
-SubTopic 325
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478873/962-325-55-17

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-05(a)(Schedule III))
-SubTopic 205
-Topic 962
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 45
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477063/962-205-45-8

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

Name:	us-gaap-ebp_EmployeeBenefitPlanChangeInNetAssetAvailableForBenefitTransferToFromExternalPlan
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Indicates (true false) whether description of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) is published and made available.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

Name:	us-gaap-ebp_EmployeeBenefitPlanDescriptionAvailable
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:booleanItemType
Balance Type:	na
Period Type:	duration

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-SubTopic 205
-Topic 962
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

Name:	us-gaap-ebp_EmployeeBenefitPlanDescriptionOfPlanLineItems
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of plan asset, in forfeited nonvested account, no longer allocated to participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

Name:	us-gaap-ebp_EmployeeBenefitPlanForfeitedNonvestedAccount
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of decrease in forfeited nonvested account of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) from employer contribution.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 962
-SubTopic 325
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478873/962-325-55-17

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (j)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-04(5)(c))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

Name:	us-gaap-ebp_EmployeeBenefitPlanForfeitedNonvestedAccountDecreaseForEmployerContribution
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of maximum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow.

Name:	us-gaap-ebp_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMaximumBorrowingAmount
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Percentage of maximum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow to total participant account balance.

Name:	us-gaap-ebp_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMaximumBorrowingToTotalAccountPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

Amount of minimum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow.

Name:	us-gaap-ebp_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMinimumBorrowingAmount
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Percentage of eligible compensation contributed for participant automatically enrolled in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantContributionAutomaticDeferralRate
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of maximum pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), is permitted to contribute to total pretax annual compensation.

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantContributionPretaxMaximumAnnualCompensationToTotalCompensationPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Interest rate on participant loan in schedule of asset held for investment of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-05(a)(Schedule I))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Employee Retirement Income Security Act of 1974
-Number 2520
-Section 103
-Subsection 10
-Paragraph b
-Subparagraph (1)(i)(D)
-Publisher DOL-EBSA

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantLoanInterestRate
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Maturity date of participant loan in schedule of asset held for investment of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), in YYYY-MM-DD format.

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantLoanMaturityDate
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

Name:	dei_LegalEntityAxis=mgr_EBP017Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=mgr_NotesReceivableUsedForThePurchaseOfAPrimaryResidenceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_InvestmentTypeAxis=us-gaap-ebp_EmployeeBenefitPlanEmployerCommonStockFundMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap-ebp_EmployeeBenefitPlanContributionParticipatingEmployerAxis=mgr_DiscretionaryContributionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap-ebp_EmployeeBenefitPlanContributionParticipatingEmployerAxis=mgr_FortSmithGroupMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantDirectedStatusAxis=mgr_ParticipantLumpSumPaymentUponTerminationOfServiceOtherThanByRetirementDisabilityOrDeathMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantDirectedStatusAxis=mgr_DistributionInDirectRolloverToAnIndividualRetirementAccountUponTerminationOfServiceOtherThanByRetirementDisabilityOrDeathInTheAbsenceOfSpecificParticipantDirectionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: