Quarterly report pursuant to Section 13 or 15(d)

LOANS, Past Due Loans (Details)

v2.4.1.9
LOANS, Past Due Loans (Details) (USD $)
3 Months Ended 9 Months Ended
Mar. 31, 2015
Payment
Sep. 30, 2014
Dec. 31, 2014
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual $ 9,711,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus   $ 8,292,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Over 90 days Accruing 100,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing   134,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
Aging of recorded investment in past due loans by class of loans [Abstract]      
30-90 Days 980,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue   671,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
Greater Than 90 Days 1,504,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue   2,170,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
Total Past Due 2,484,000us-gaap_FinancingReceivableRecordedInvestmentPastDue   2,841,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
Loans Not Past Due 1,132,827,000us-gaap_FinancingReceivableRecordedInvestmentCurrent   1,115,642,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
Total ending loans balance 1,135,311,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome   1,118,483,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Specific reserves allocated to customers with modified term loans in troubled debt restructurings 4,443,000mcbc_TroubledDebtRestructuringLoansAndLeasesReceivableSpecificAllowanceDuringPeriod   4,065,000mcbc_TroubledDebtRestructuringLoansAndLeasesReceivableSpecificAllowanceDuringPeriod
Number of consecutive payment before nonaccrual restructured loan is upgraded 6mcbc_NumberOfConsecutivePaymentBeforeNonaccrualRestructuredLoanIsUpgraded    
Reduction of loans designated as TDR and impaired   5,900,000mcbc_FinancingReceivableModifiedAndImpairedIncreaseDecreaseInRecordedInvestment  
Number of months of performance before a loan is removed from TDR 6 months    
Commercial and Industrial [Member]      
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual 6,732,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
  5,605,000us-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]      
30-90 Days 0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
  54,000mcbc_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 0us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
  54,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Loans Not Past Due 341,530,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
  327,620,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Total ending loans balance 341,530,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
  327,674,000us-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 2,586,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
  1,906,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
Over 90 days Accruing 24,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
  117,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30-90 Days 973,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
  200,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
Greater Than 90 Days 1,086,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
  1,427,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
Total Past Due 2,059,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
  1,627,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
Loans Not Past Due 486,013,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
  488,904,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
Total ending loans balance 488,072,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
  490,531,000us-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 213,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialDevelopedFinancingReceivableMember
  245,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialDevelopedFinancingReceivableMember
Over 90 days Accruing 0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialDevelopedFinancingReceivableMember
  0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialDevelopedFinancingReceivableMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30-90 Days 0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialDevelopedFinancingReceivableMember
  0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialDevelopedFinancingReceivableMember
Greater Than 90 Days 0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialDevelopedFinancingReceivableMember
  0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialDevelopedFinancingReceivableMember
Total Past Due 0us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialDevelopedFinancingReceivableMember
  0us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialDevelopedFinancingReceivableMember
Loans Not Past Due 12,143,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialDevelopedFinancingReceivableMember
  12,771,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialDevelopedFinancingReceivableMember
Total ending loans balance 12,143,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialDevelopedFinancingReceivableMember
  12,771,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialDevelopedFinancingReceivableMember
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]      
30-90 Days 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 7,221,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateUnsecuredToResidentialDevelopersReceivableMember
  7,496,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateUnsecuredToResidentialDevelopersReceivableMember
Total ending loans balance 7,221,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateUnsecuredToResidentialDevelopersReceivableMember
  7,496,000us-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 24,000us-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]      
30-90 Days 0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
  100,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
Greater Than 90 Days 24,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
  0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
Total Past Due 24,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
  100,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
Loans Not Past Due 50,079,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
  50,272,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
Total ending loans balance 50,103,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateVacantAndUnimprovedReceivableMember
  50,372,000us-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 49,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
  29,000us-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]      
30-90 Days 0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
  0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
Greater Than 90 Days 49,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
  29,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
Total Past Due 49,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
  29,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
Loans Not Past Due 1,684,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
  4,053,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
Total ending loans balance 1,733,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialDevelopmentFinancingReceivableMember
  4,082,000us-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 604,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
  766,000us-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]      
30-90 Days 14,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
  100,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
Greater Than 90 Days 440,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
  440,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
Total Past Due 454,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
  540,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
Loans Not Past Due 67,911,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
  69,072,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
Total ending loans balance 68,365,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateResidentialImprovedFinancingReceivableMember
  69,612,000us-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 1,720,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
  866,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
Over 90 days Accruing 0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
  117,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30-90 Days 959,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
  0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
Greater Than 90 Days 573,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
  958,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
Total Past Due 1,532,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
  958,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
Loans Not Past Due 272,268,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
  268,799,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
Total ending loans balance 273,800,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateCommercialImprovedFinancingReceivableMember
  269,757,000us-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]      
30-90 Days 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 74,707,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateManufacturingAndIndustrialFinancingReceivableMember
  76,441,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateManufacturingAndIndustrialFinancingReceivableMember
Total ending loans balance 74,707,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_CommercialRealEstateManufacturingAndIndustrialFinancingReceivableMember
  76,441,000us-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 393,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
  781,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
Over 90 days Accruing 76,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
  17,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30-90 Days 7,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
  417,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
Greater Than 90 Days 418,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
  743,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
Total Past Due 425,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
  1,160,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
Loans Not Past Due 305,284,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
  299,118,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
Total ending loans balance 305,709,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
  300,278,000us-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 64,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
  305,000us-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]      
30-90 Days 0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
  338,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
Greater Than 90 Days 62,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
  303,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
Total Past Due 62,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
  641,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
Loans Not Past Due 198,980,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
  189,608,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
Total ending loans balance 199,042,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
  190,249,000us-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 37,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_ConsumerUnsecuredFinancingReceivableMember
  40,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_ConsumerUnsecuredFinancingReceivableMember
Over 90 days Accruing 0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_ConsumerUnsecuredFinancingReceivableMember
  0us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_ConsumerUnsecuredFinancingReceivableMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30-90 Days 6,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_ConsumerUnsecuredFinancingReceivableMember
  0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_ConsumerUnsecuredFinancingReceivableMember
Greater Than 90 Days 0us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_ConsumerUnsecuredFinancingReceivableMember
  18,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_ConsumerUnsecuredFinancingReceivableMember
Total Past Due 6,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_ConsumerUnsecuredFinancingReceivableMember
  18,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_ConsumerUnsecuredFinancingReceivableMember
Loans Not Past Due 815,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_ConsumerUnsecuredFinancingReceivableMember
  930,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_ConsumerUnsecuredFinancingReceivableMember
Total ending loans balance 821,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_ConsumerUnsecuredFinancingReceivableMember
  948,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mcbc_ConsumerUnsecuredFinancingReceivableMember
Home Equity [Member]      
Recorded investment in nonaccrual and loans past due over 90 days still on accrual by class of loans [Abstract]      
Nonaccrual 292,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
  436,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Over 90 days Accruing 76,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
  17,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Aging of recorded investment in past due loans by class of loans [Abstract]      
30-90 Days 1,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
  79,000mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Greater Than 90 Days 356,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
  422,000us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Total Past Due 357,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
  501,000us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Loans Not Past Due 95,413,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
  98,386,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Total ending loans balance 95,770,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
  98,887,000us-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]      
30-90 Days 0mcbc_FinancingReceivableRecordedInvestment30To90DaysPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
  0mcbc_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
  0us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
Loans Not Past Due 10,076,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
  10,194,000us-gaap_FinancingReceivableRecordedInvestmentCurrent
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
Total ending loans balance $ 10,076,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember
  $ 10,194,000us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerOtherFinancingReceivableMember