Annual report pursuant to Section 13 and 15(d)

LOANS, Past Due Loans (Details)

v2.4.1.9
LOANS, Past Due Loans (Details) (USD $)
9 Months Ended 12 Months Ended
Sep. 30, 2014
Dec. 31, 2014
Payment
Dec. 31, 2013
Payment
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual   $ 8,292,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus $ 12,182,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Over 90 days Accruing   134,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing 153,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
Aging of recorded investment in past due loans by class of loans [Abstract]      
30 to 90 days past due   671,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue 1,095,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
Greater than 90 days   2,170,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue 4,425,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
Total past due   2,841,000us-gaap_FinancingReceivableRecordedInvestmentPastDue 5,520,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
Loans not past due   1,115,642,000us-gaap_FinancingReceivableRecordedInvestmentCurrent 1,036,857,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
Total ending loans balance   1,118,483,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome 1,042,377,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Specific reserves allocated to customers with modified term loans in troubled debt restructurings   4,065,000mcbc_TroubledDebtRestructuringLoansAndLeasesReceivableSpecificAllowanceDuringPeriod 3,870,000mcbc_TroubledDebtRestructuringLoansAndLeasesReceivableSpecificAllowanceDuringPeriod
Number of consecutive payment before nonaccrual restructured loan is upgraded   6mcbc_NumberOfConsecutivePaymentBeforeNonaccrualRestructuredLoanIsUpgraded 6mcbc_NumberOfConsecutivePaymentBeforeNonaccrualRestructuredLoanIsUpgraded
Number of months of performance before a loan is removed from TDR   6 months 6 months
Reduction in loans designated as TDR and impaired 5,900,000mcbc_FinancingReceivableModifiedAndImpairedIncreaseDecreaseInRecordedInvestment    
Commercial and Industrial [Member]      
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual   5,605,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
5,625,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Over 90 days Accruing   0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30 to 90 days past due   54,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Greater than 90 days   0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Total past due   54,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
0us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Loans not past due   327,620,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
274,099,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Total ending loans balance   327,674,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
274,099,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Commercial Real Estate [Member]      
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual   1,906,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
5,553,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
Over 90 days Accruing   117,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
153,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30 to 90 days past due   200,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
679,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
Greater than 90 days   1,427,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
4,425,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
Total past due   1,627,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
5,104,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
Loans not past due   488,904,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
467,236,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
Total ending loans balance   490,531,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
472,340,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
Residential Developed [Member]      
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual   245,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
2,590,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
Over 90 days Accruing   0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
153,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30 to 90 days past due   0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
143,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
Greater than 90 days   0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
2,296,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
Total past due   0us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
2,439,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
Loans not past due   12,771,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
15,691,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
Total ending loans balance   12,771,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
18,130,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
Unsecured to Residential Developers [Member]      
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual   0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateUnsecuredToResidentialDevelopersReceivableMember
0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateUnsecuredToResidentialDevelopersReceivableMember
Over 90 days Accruing   0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateUnsecuredToResidentialDevelopersReceivableMember
0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateUnsecuredToResidentialDevelopersReceivableMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30 to 90 days past due   0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateUnsecuredToResidentialDevelopersReceivableMember
0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateUnsecuredToResidentialDevelopersReceivableMember
Greater than 90 days   0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateUnsecuredToResidentialDevelopersReceivableMember
0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateUnsecuredToResidentialDevelopersReceivableMember
Total past due   0us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateUnsecuredToResidentialDevelopersReceivableMember
0us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateUnsecuredToResidentialDevelopersReceivableMember
Loans not past due   7,496,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateUnsecuredToResidentialDevelopersReceivableMember
7,315,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateUnsecuredToResidentialDevelopersReceivableMember
Total ending loans balance   7,496,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateUnsecuredToResidentialDevelopersReceivableMember
7,315,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateUnsecuredToResidentialDevelopersReceivableMember
Vacant and Unimproved [Member]      
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual   0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
Over 90 days Accruing   0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30 to 90 days past due   100,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
Greater than 90 days   0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
Total past due   100,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
0us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
Loans not past due   50,272,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
42,988,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
Total ending loans balance   50,372,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
42,988,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
Commercial Development [Member]      
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual   29,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
23,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
Over 90 days Accruing   0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30 to 90 days past due   0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
Greater than 90 days   29,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
23,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
Total past due   29,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
23,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
Loans not past due   4,053,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
2,411,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
Total ending loans balance   4,082,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
2,434,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
Residential Improved [Member]      
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual   766,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
429,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
Over 90 days Accruing   0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30 to 90 days past due   100,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
98,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
Greater than 90 days   440,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
50,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
Total past due   540,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
148,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
Loans not past due   69,072,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
76,146,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
Total ending loans balance   69,612,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
76,294,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
Commercial Improved [Member]      
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual   866,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
2,511,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
Over 90 days Accruing   117,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30 to 90 days past due   0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
438,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
Greater than 90 days   958,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
2,056,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
Total past due   958,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
2,494,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
Loans not past due   268,799,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
244,701,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
Total ending loans balance   269,757,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
247,195,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
Manufacturing and Industrial [Member]      
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual   0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateManufacturingAndIndustrialFinancingReceivableMember
0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateManufacturingAndIndustrialFinancingReceivableMember
Over 90 days Accruing   0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateManufacturingAndIndustrialFinancingReceivableMember
0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateManufacturingAndIndustrialFinancingReceivableMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30 to 90 days past due   0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateManufacturingAndIndustrialFinancingReceivableMember
0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateManufacturingAndIndustrialFinancingReceivableMember
Greater than 90 days   0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateManufacturingAndIndustrialFinancingReceivableMember
0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateManufacturingAndIndustrialFinancingReceivableMember
Total past due   0us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateManufacturingAndIndustrialFinancingReceivableMember
0us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateManufacturingAndIndustrialFinancingReceivableMember
Loans not past due   76,441,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateManufacturingAndIndustrialFinancingReceivableMember
77,984,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateManufacturingAndIndustrialFinancingReceivableMember
Total ending loans balance   76,441,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateManufacturingAndIndustrialFinancingReceivableMember
77,984,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateManufacturingAndIndustrialFinancingReceivableMember
Consumer Loan [Member]      
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual   781,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
1,004,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
Over 90 days Accruing   17,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30 to 90 days past due   417,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
416,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
Greater than 90 days   743,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
Total past due   1,160,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
416,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
Loans not past due   299,118,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
295,522,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
Total ending loans balance   300,278,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
295,938,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
Residential Mortgage [Member]      
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual   305,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
639,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
Over 90 days Accruing   0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30 to 90 days past due   338,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
78,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
Greater than 90 days   303,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
Total past due   641,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
78,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
Loans not past due   189,608,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
188,570,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
Total ending loans balance   190,249,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
188,648,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
Unsecured [Member]      
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual   40,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnsecuredDebtMember
33,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnsecuredDebtMember
Over 90 days Accruing   0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnsecuredDebtMember
0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnsecuredDebtMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30 to 90 days past due   0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnsecuredDebtMember
9,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnsecuredDebtMember
Greater than 90 days   18,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnsecuredDebtMember
0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnsecuredDebtMember
Total past due   18,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnsecuredDebtMember
9,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnsecuredDebtMember
Loans not past due   930,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnsecuredDebtMember
1,328,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnsecuredDebtMember
Total ending loans balance   948,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnsecuredDebtMember
1,337,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnsecuredDebtMember
Home Equity [Member]      
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual   436,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
332,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Over 90 days Accruing   17,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30 to 90 days past due   79,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
317,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Greater than 90 days   422,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Total past due   501,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
317,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Loans not past due   98,386,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
95,644,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Total ending loans balance   98,887,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
95,961,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Other Secured [Member]      
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual   0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
Over 90 days Accruing   0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30 to 90 days past due   0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
12,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
Greater than 90 days   0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
Total past due   0us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
12,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
Loans not past due   10,194,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
9,980,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
Total ending loans balance   $ 10,194,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
$ 9,992,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember