Name:	mcbc_ContractualPeriodOfLoan
Namespace Prefix:	mcbc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Amount of fees collected from Small Business Administration for loans originated.

No definition available.

Name:	mcbc_FeesReceivedForLoansOriginated
Namespace Prefix:	mcbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of fees recognized for loans forgiven by Small Business Administration (SBA).

No definition available.

Name:	mcbc_FeesRecognizedForLoansForgiven
Namespace Prefix:	mcbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of fees unrecognized for outstanding loans.

No definition available.

Name:	mcbc_FeesUnrecognizedForOutstandingLoans
Namespace Prefix:	mcbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of financing receivable modified by other than troubled debt restructurings during the period.

No definition available.

Name:	mcbc_FinancingReceivableModificationsByOtherThanTroubledDebtRestructuringsAggregatePrincipalBalance
Namespace Prefix:	mcbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Number of financing receivables that have been modified by other than troubled debt restructurings.

No definition available.

Name:	mcbc_FinancingReceivableModificationsByOtherThanTroubledDebtRestructuringsNumberOfContracts
Namespace Prefix:	mcbc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Amount of loans forgiven by SBA during the period.

No definition available.

Name:	mcbc_FinancingReceivablesLoansForgiven
Namespace Prefix:	mcbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of loans outstanding as of the balance sheet date.

No definition available.

Name:	mcbc_FinancingReceivablesLoansOutstanding
Namespace Prefix:	mcbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of loans originated during the period.

No definition available.

Name:	mcbc_LoansOriginated
Namespace Prefix:	mcbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Refers to the number of full service branch offices.

No definition available.

Name:	mcbc_NumberOfFullServiceBranchOffices
Namespace Prefix:	mcbc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Number of loans forgiven under Payment Protection Program (PPP) during the period.

No definition available.

Name:	mcbc_NumberOfLoansForgiven
Namespace Prefix:	mcbc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Number of loans originated under Payment Protection Program (PPP) during the period.

No definition available.

Name:	mcbc_NumberOfLoansOriginated
Namespace Prefix:	mcbc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Number of loans outstanding under Payment Protection Program (PPP) during the period.

No definition available.

Name:	mcbc_NumberOfLoansOutstanding
Namespace Prefix:	mcbc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

Name:	mcbc_RecentEventsAbstract
Namespace Prefix:	mcbc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

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

Name:	us-gaap_LoanRestructuringModificationAxis=us-gaap_PaymentDeferralMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mcbc_PaycheckProtectionProgramLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

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