Quarterly report pursuant to Section 13 or 15(d)

COMMITMENTS AND OFF BALANCE-SHEET RISK (Details)

v2.4.1.9
COMMITMENTS AND OFF BALANCE-SHEET RISK (Details) (USD $)
 3 Months Ended 12 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Summary of the contractual amounts of financial instruments with off-balance-sheet risk [Abstract]    
Notional amount of commitments to fund mortgage loans to be sold into the secondary market $ 22,500,000us-gaap_FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability $ 14,200,000us-gaap_FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability
Commitments to make loans at fixed rates (in hundredths) 61.00%mcbc_CommitmentsToMakeLoansAtFixedRates  
Expiration period of commitment to make variable rate loan 30 days  
Commitments to Make Loans [Member]    
Summary of the contractual amounts of financial instruments with off-balance-sheet risk [Abstract]    
Contractual amounts of financial instruments with off-balance-sheet risk 124,754,000us-gaap_ConcentrationRiskCreditRiskFinancialInstrumentMaximumExposure
/ us-gaap_FinancialInstrumentAxis
= us-gaap_CommitmentsToExtendCreditMember 		81,274,000us-gaap_ConcentrationRiskCreditRiskFinancialInstrumentMaximumExposure
/ us-gaap_FinancialInstrumentAxis
= us-gaap_CommitmentsToExtendCreditMember
Letters of Credit [Member]    
Summary of the contractual amounts of financial instruments with off-balance-sheet risk [Abstract]    
Contractual amounts of financial instruments with off-balance-sheet risk 12,121,000us-gaap_ConcentrationRiskCreditRiskFinancialInstrumentMaximumExposure
/ us-gaap_FinancialInstrumentAxis
= us-gaap_LetterOfCreditMember 		11,862,000us-gaap_ConcentrationRiskCreditRiskFinancialInstrumentMaximumExposure
/ us-gaap_FinancialInstrumentAxis
= us-gaap_LetterOfCreditMember
Unused Lines of Credit [Member]    
Summary of the contractual amounts of financial instruments with off-balance-sheet risk [Abstract]    
Contractual amounts of financial instruments with off-balance-sheet risk $ 361,626,000us-gaap_ConcentrationRiskCreditRiskFinancialInstrumentMaximumExposure
/ us-gaap_FinancialInstrumentAxis
= us-gaap_UnusedLinesOfCreditMember 		$ 389,099,000us-gaap_ConcentrationRiskCreditRiskFinancialInstrumentMaximumExposure
/ us-gaap_FinancialInstrumentAxis
= us-gaap_UnusedLinesOfCreditMember