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v2.4.1.9

Note 4 - Loans and Allowance for Loan Losses (Details) - Impaired Loans (USD $) | 12 Months Ended
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Dec. 31, 2014 | Dec. 31, 2013
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance |  | $ 12,386,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance
Commercial: |  |
Impaired loans, related allowance |  | 12,386,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance
Total impaired loans: |  |
Impaired loans, unpaid contractual principal balance |  | 41,056,000 us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
Impaired loans, recorded principal balance |  | 36,868,000 us-gaap_ImpairedFinancingReceivableRecordedInvestment
Impaired loans, related allowance |  | 12,386,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance
Impaired loans, average recorded principal balance |  | 49,961,000 us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
Originated Loan [Member] | With No Related Allowance [Member] | Commercial and Industrial [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 1,170,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember | 2,229,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember
Impaired loans with no related allowance recorded, recorded principal balance | 1,164,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember | 511,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember
Impaired loans with no related allowance recorded, average recorded principal balance | 652,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember | 1,205,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember
Originated Loan [Member] | With No Related Allowance [Member] | Commercial Vacant Land and Land Development and Residential Construction Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 540,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember | 475,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember
Impaired loans with no related allowance recorded, recorded principal balance | 209,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember | 362,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember
Impaired loans with no related allowance recorded, average recorded principal balance | 227,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember | 991,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember
Originated Loan [Member] | With No Related Allowance [Member] | Commercial Real Estate Owner Occupied Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 3,609,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember | 1,270,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember
Impaired loans with no related allowance recorded, recorded principal balance | 1,901,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember | 785,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember
Impaired loans with no related allowance recorded, average recorded principal balance | 4,365,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember | 1,084,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember
Originated Loan [Member] | With No Related Allowance [Member] | Commercial Real Estate Non Owner Occupied Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 1,210,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember | 895,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember
Impaired loans with no related allowance recorded, recorded principal balance | 1,210,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember | 733,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember
Impaired loans with no related allowance recorded, average recorded principal balance | 971,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember | 4,049,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember
Originated Loan [Member] | With No Related Allowance [Member] | Commercial Real Estate Multi Family and Residential Rental Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 375,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember | 41,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember
Impaired loans with no related allowance recorded, recorded principal balance | 317,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember | 1,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember
Impaired loans with no related allowance recorded, average recorded principal balance | 64,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember | 390,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember
Originated Loan [Member] | With No Related Allowance [Member] | Commercial Portfolio Segment [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 6,904,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 4,910,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Impaired loans with no related allowance recorded, recorded principal balance | 4,801,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 2,392,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Impaired loans with no related allowance recorded, average recorded principal balance | 6,279,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 7,719,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Originated Loan [Member] | With No Related Allowance [Member] | Retail Home Equity and Other [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 207,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember | 507,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember
Impaired loans with no related allowance recorded, recorded principal balance | 191,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember | 461,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember
Impaired loans with no related allowance recorded, average recorded principal balance | 517,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember | 471,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember
Originated Loan [Member] | With No Related Allowance [Member] | Retail 1-4 Family Mortgages [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 1,144,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember | 1,272,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember
Impaired loans with no related allowance recorded, recorded principal balance | 560,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember | 647,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember
Impaired loans with no related allowance recorded, average recorded principal balance | 585,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember | 727,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember
Originated Loan [Member] | With No Related Allowance [Member] | Retail Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 1,351,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember | 1,779,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember
Impaired loans with no related allowance recorded, recorded principal balance | 751,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember | 1,108,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember
Impaired loans with no related allowance recorded, average recorded principal balance | 1,102,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember | 1,198,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember
Originated Loan [Member] | With No Related Allowance [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 8,255,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember | 6,689,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember
Impaired loans with no related allowance recorded, recorded principal balance | 5,552,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember | 3,500,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember
Impaired loans with no related allowance recorded, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember
Impaired loans with no related allowance recorded, average recorded principal balance | 7,381,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember | 8,917,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember
Commercial: |  |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember
Total impaired loans: |  |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember
Originated Loan [Member] | With An Allowance Recorded [Member] | Commercial and Industrial [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 1,578,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 5,299,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Impaired loans with an allowance recorded, recorded principal balance | 5,226,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Impaired loans, related allowance | 1,578,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Impaired loans with an allowance recorded, average recorded principal balance | 2,759,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Total impaired loans: |  |
Impaired loans, related allowance | 1,578,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Originated Loan [Member] | With An Allowance Recorded [Member] | Commercial Vacant Land and Land Development and Residential Construction Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 151,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 2,000,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Impaired loans with an allowance recorded, recorded principal balance | 2,000,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Impaired loans, related allowance | 151,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Impaired loans with an allowance recorded, average recorded principal balance | 3,229,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Total impaired loans: |  |
Impaired loans, related allowance | 151,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Originated Loan [Member] | With An Allowance Recorded [Member] | Commercial Real Estate Owner Occupied Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 2,200,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 15,745,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Impaired loans with an allowance recorded, recorded principal balance | 15,674,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Impaired loans, related allowance | 2,200,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Impaired loans with an allowance recorded, average recorded principal balance | 4,630,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Total impaired loans: |  |
Impaired loans, related allowance | 2,200,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Originated Loan [Member] | With An Allowance Recorded [Member] | Commercial Real Estate Non Owner Occupied Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 4,779,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 16,033,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Impaired loans with an allowance recorded, recorded principal balance | 15,949,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Impaired loans, related allowance | 4,779,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Impaired loans with an allowance recorded, average recorded principal balance | 18,245,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Total impaired loans: |  |
Impaired loans, related allowance | 4,779,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Originated Loan [Member] | With An Allowance Recorded [Member] | Commercial Real Estate Multi Family and Residential Rental Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 666,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 1,371,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Impaired loans with an allowance recorded, recorded principal balance | 1,371,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Impaired loans, related allowance | 666,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Impaired loans with an allowance recorded, average recorded principal balance | 1,700,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Total impaired loans: |  |
Impaired loans, related allowance | 666,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Originated Loan [Member] | With An Allowance Recorded [Member] | Commercial Portfolio Segment [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 9,374,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 40,448,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Impaired loans with an allowance recorded, recorded principal balance | 40,220,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Impaired loans, related allowance | 9,374,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Impaired loans with an allowance recorded, average recorded principal balance | 30,563,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Total impaired loans: |  |
Impaired loans, related allowance | 9,374,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Originated Loan [Member] | With An Allowance Recorded [Member] | Retail Home Equity and Other [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 84,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 115,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Impaired loans with an allowance recorded, recorded principal balance | 84,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Impaired loans, related allowance | 84,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Impaired loans with an allowance recorded, average recorded principal balance | 128,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Total impaired loans: |  |
Impaired loans, related allowance | 84,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Originated Loan [Member] | With An Allowance Recorded [Member] | Retail 1-4 Family Mortgages [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 694,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 2,194,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Impaired loans with an allowance recorded, recorded principal balance | 2,000,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Impaired loans, related allowance | 694,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Impaired loans with an allowance recorded, average recorded principal balance | 2,115,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Total impaired loans: |  |
Impaired loans, related allowance | 694,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Originated Loan [Member] | With An Allowance Recorded [Member] | Retail Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 778,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 2,309,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Impaired loans with an allowance recorded, recorded principal balance | 2,084,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Impaired loans, related allowance | 778,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Impaired loans with an allowance recorded, average recorded principal balance | 2,243,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Total impaired loans: |  |
Impaired loans, related allowance | 778,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Originated Loan [Member] | With An Allowance Recorded [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 10,152,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 42,757,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember |
Impaired loans with an allowance recorded, recorded principal balance | 42,304,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember |
Impaired loans, related allowance | 10,152,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember |
Impaired loans with an allowance recorded, average recorded principal balance | 32,806,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember |
Total impaired loans: |  |
Impaired loans, related allowance | 10,152,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember |
Originated Loan [Member] | Commercial Portfolio Segment [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 9,374,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Commercial: |  |
Impaired loans, related allowance | 9,374,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Total impaired loans: |  |
Impaired loans, unpaid contractual principal balance | 47,352,000 us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Impaired loans, recorded principal balance | 45,021,000 us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Impaired loans, related allowance | 9,374,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Impaired loans, average recorded principal balance | 36,842,000 us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Originated Loan [Member] | Retail Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 778,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Commercial: |  |
Impaired loans, related allowance | 778,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Total impaired loans: |  |
Impaired loans, unpaid contractual principal balance | 3,660,000 us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Impaired loans, recorded principal balance | 2,835,000 us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Impaired loans, related allowance | 778,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Impaired loans, average recorded principal balance | 3,345,000 us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Originated Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 10,152,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember |
Commercial: |  |
Impaired loans, related allowance | 10,152,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember |
Total impaired loans: |  |
Impaired loans, unpaid contractual principal balance | 51,012,000 us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember |
Impaired loans, recorded principal balance | 47,856,000 us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember |
Impaired loans, related allowance | 10,152,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember |
Impaired loans, average recorded principal balance | 40,187,000 us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember |
Acquired Loan [Member] | With No Related Allowance [Member] | Commercial and Industrial [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 1,586,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Impaired loans with no related allowance recorded, recorded principal balance | 1,579,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Impaired loans with no related allowance recorded, average recorded principal balance | 563,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Acquired Loan [Member] | With No Related Allowance [Member] | Commercial Vacant Land and Land Development and Residential Construction Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 0 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Impaired loans with no related allowance recorded, recorded principal balance | 0 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Impaired loans with no related allowance recorded, average recorded principal balance | 0 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Acquired Loan [Member] | With No Related Allowance [Member] | Commercial Real Estate Owner Occupied Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 113,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Impaired loans with no related allowance recorded, recorded principal balance | 113,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Impaired loans with no related allowance recorded, average recorded principal balance | 52,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Acquired Loan [Member] | With No Related Allowance [Member] | Commercial Real Estate Non Owner Occupied Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 326,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Impaired loans with no related allowance recorded, recorded principal balance | 326,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Impaired loans with no related allowance recorded, average recorded principal balance | 260,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Acquired Loan [Member] | With No Related Allowance [Member] | Commercial Real Estate Multi Family and Residential Rental Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 487,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Impaired loans with no related allowance recorded, recorded principal balance | 487,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Impaired loans with no related allowance recorded, average recorded principal balance | 166,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Acquired Loan [Member] | With No Related Allowance [Member] | Commercial Portfolio Segment [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 2,512,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Impaired loans with no related allowance recorded, recorded principal balance | 2,505,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Impaired loans with no related allowance recorded, average recorded principal balance | 1,041,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Acquired Loan [Member] | With No Related Allowance [Member] | Retail Home Equity and Other [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 641,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Impaired loans with no related allowance recorded, recorded principal balance | 639,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Impaired loans with no related allowance recorded, average recorded principal balance | 262,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Acquired Loan [Member] | With No Related Allowance [Member] | Retail 1-4 Family Mortgages [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 866,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Impaired loans with no related allowance recorded, recorded principal balance | 866,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Impaired loans with no related allowance recorded, average recorded principal balance | 458,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Acquired Loan [Member] | With No Related Allowance [Member] | Retail Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 1,507,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Impaired loans with no related allowance recorded, recorded principal balance | 1,505,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Impaired loans with no related allowance recorded, average recorded principal balance | 720,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Acquired Loan [Member] | With No Related Allowance [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, unpaid contractual principal balance | 4,019,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Impaired loans with no related allowance recorded, recorded principal balance | 4,010,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Impaired loans with no related allowance recorded, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Impaired loans with no related allowance recorded, average recorded principal balance | 1,761,000 us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Commercial: |  |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Total impaired loans: |  |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithNoRelatedAllowanceMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Acquired Loan [Member] | With An Allowance Recorded [Member] | Commercial and Industrial [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Impaired loans with an allowance recorded, recorded principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Impaired loans with an allowance recorded, average recorded principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Total impaired loans: |  |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Acquired Loan [Member] | With An Allowance Recorded [Member] | Commercial Vacant Land and Land Development and Residential Construction Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Impaired loans with an allowance recorded, recorded principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Impaired loans with an allowance recorded, average recorded principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Total impaired loans: |  |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Acquired Loan [Member] | With An Allowance Recorded [Member] | Commercial Real Estate Owner Occupied Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 605,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 1,516,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Impaired loans with an allowance recorded, recorded principal balance | 1,502,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Impaired loans, related allowance | 605,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Impaired loans with an allowance recorded, average recorded principal balance | 501,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Total impaired loans: |  |
Impaired loans, related allowance | 605,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Acquired Loan [Member] | With An Allowance Recorded [Member] | Commercial Real Estate Non Owner Occupied Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Impaired loans with an allowance recorded, recorded principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Impaired loans with an allowance recorded, average recorded principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Total impaired loans: |  |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Acquired Loan [Member] | With An Allowance Recorded [Member] | Commercial Real Estate Multi Family and Residential Rental Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Impaired loans with an allowance recorded, recorded principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Impaired loans with an allowance recorded, average recorded principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Total impaired loans: |  |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Acquired Loan [Member] | With An Allowance Recorded [Member] | Commercial Portfolio Segment [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 605,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 1,516,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Impaired loans with an allowance recorded, recorded principal balance | 1,502,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Impaired loans, related allowance | 605,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Impaired loans with an allowance recorded, average recorded principal balance | 501,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Total impaired loans: |  |
Impaired loans, related allowance | 605,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Acquired Loan [Member] | With An Allowance Recorded [Member] | Retail Home Equity and Other [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Impaired loans with an allowance recorded, recorded principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Impaired loans with an allowance recorded, average recorded principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Total impaired loans: |  |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Acquired Loan [Member] | With An Allowance Recorded [Member] | Retail 1-4 Family Mortgages [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Impaired loans with an allowance recorded, recorded principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Impaired loans with an allowance recorded, average recorded principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Total impaired loans: |  |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Acquired Loan [Member] | With An Allowance Recorded [Member] | Retail Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Impaired loans with an allowance recorded, recorded principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Impaired loans with an allowance recorded, average recorded principal balance | 0 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Total impaired loans: |  |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Acquired Loan [Member] | With An Allowance Recorded [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 605,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance | 1,516,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Impaired loans with an allowance recorded, recorded principal balance | 1,502,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Impaired loans, related allowance | 605,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Impaired loans with an allowance recorded, average recorded principal balance | 501,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Total impaired loans: |  |
Impaired loans, related allowance | 605,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Acquired Loan [Member] | Commercial Portfolio Segment [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 605,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Commercial: |  |
Impaired loans, related allowance | 605,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Total impaired loans: |  |
Impaired loans, unpaid contractual principal balance | 4,028,000 us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Impaired loans, recorded principal balance | 4,007,000 us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Impaired loans, related allowance | 605,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Impaired loans, average recorded principal balance | 1,542,000 us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Acquired Loan [Member] | Retail Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Commercial: |  |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Total impaired loans: |  |
Impaired loans, unpaid contractual principal balance | 1,507,000 us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Impaired loans, recorded principal balance | 1,505,000 us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Impaired loans, related allowance | 0 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Impaired loans, average recorded principal balance | 720,000 us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Acquired Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance | 605,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Commercial: |  |
Impaired loans, related allowance | 605,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Total impaired loans: |  |
Impaired loans, unpaid contractual principal balance | 5,535,000 us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Impaired loans, recorded principal balance | 5,512,000 us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Impaired loans, related allowance | 605,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Impaired loans, average recorded principal balance | 2,262,000 us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
With An Allowance Recorded [Member] | Commercial and Industrial [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance |  | 792,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance |  | 1,517,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember
Impaired loans with an allowance recorded, recorded principal balance |  | 1,440,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember
Impaired loans, related allowance |  | 792,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember
Impaired loans with an allowance recorded, average recorded principal balance |  | 1,880,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember
Total impaired loans: |  |
Impaired loans, related allowance |  | 792,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember
With An Allowance Recorded [Member] | Commercial Vacant Land and Land Development and Residential Construction Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance |  | 844,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance |  | 4,436,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember
Impaired loans with an allowance recorded, recorded principal balance |  | 4,139,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember
Impaired loans, related allowance |  | 844,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember
Impaired loans with an allowance recorded, average recorded principal balance |  | 3,354,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember
Total impaired loans: |  |
Impaired loans, related allowance |  | 844,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember
With An Allowance Recorded [Member] | Commercial Real Estate Owner Occupied Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance |  | 528,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance |  | 1,513,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember
Impaired loans with an allowance recorded, recorded principal balance |  | 1,513,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember
Impaired loans, related allowance |  | 528,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember
Impaired loans with an allowance recorded, average recorded principal balance |  | 2,550,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember
Total impaired loans: |  |
Impaired loans, related allowance |  | 528,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember
With An Allowance Recorded [Member] | Commercial Real Estate Non Owner Occupied Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance |  | 7,969,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance |  | 21,088,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember
Impaired loans with an allowance recorded, recorded principal balance |  | 21,072,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember
Impaired loans, related allowance |  | 7,969,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember
Impaired loans with an allowance recorded, average recorded principal balance |  | 28,388,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember
Total impaired loans: |  |
Impaired loans, related allowance |  | 7,969,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember
With An Allowance Recorded [Member] | Commercial Real Estate Multi Family and Residential Rental Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance |  | 1,127,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance |  | 3,219,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember
Impaired loans with an allowance recorded, recorded principal balance |  | 2,684,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember
Impaired loans, related allowance |  | 1,127,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember
Impaired loans with an allowance recorded, average recorded principal balance |  | 2,915,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember
Total impaired loans: |  |
Impaired loans, related allowance |  | 1,127,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember
With An Allowance Recorded [Member] | Commercial Portfolio Segment [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance |  | 11,260,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance |  | 31,773,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Impaired loans with an allowance recorded, recorded principal balance |  | 30,848,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Impaired loans, related allowance |  | 11,260,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Impaired loans with an allowance recorded, average recorded principal balance |  | 39,087,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Total impaired loans: |  |
Impaired loans, related allowance |  | 11,260,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
With An Allowance Recorded [Member] | Retail Home Equity and Other [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance |  | 96,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance |  | 320,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember
Impaired loans with an allowance recorded, recorded principal balance |  | 289,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember
Impaired loans, related allowance |  | 96,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember
Impaired loans with an allowance recorded, average recorded principal balance |  | 329,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember
Total impaired loans: |  |
Impaired loans, related allowance |  | 96,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember
With An Allowance Recorded [Member] | Retail 1-4 Family Mortgages [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance |  | 1,030,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance |  | 2,274,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember
Impaired loans with an allowance recorded, recorded principal balance |  | 2,231,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember
Impaired loans, related allowance |  | 1,030,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember
Impaired loans with an allowance recorded, average recorded principal balance |  | 1,628,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember
Total impaired loans: |  |
Impaired loans, related allowance |  | 1,030,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember
With An Allowance Recorded [Member] | Retail Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance |  | 1,126,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance |  | 2,594,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember
Impaired loans with an allowance recorded, recorded principal balance |  | 2,520,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember
Impaired loans, related allowance |  | 1,126,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember
Impaired loans with an allowance recorded, average recorded principal balance |  | 1,957,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember
Total impaired loans: |  |
Impaired loans, related allowance |  | 1,126,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember
With An Allowance Recorded [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance |  | 12,386,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember
Commercial: |  |
Impaired loans with an allowance recorded, unpaid contractual principal balance |  | 34,367,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember
Impaired loans with an allowance recorded, recorded principal balance |  | 33,368,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember
Impaired loans, related allowance |  | 12,386,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember
Impaired loans with an allowance recorded, average recorded principal balance |  | 41,044,000 us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember
Total impaired loans: |  |
Impaired loans, related allowance |  | 12,386,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = mbwm_WithAnAllowanceRecordedMember
Commercial Portfolio Segment [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance |  | 11,260,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Commercial: |  |
Impaired loans, related allowance |  | 11,260,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Total impaired loans: |  |
Impaired loans, unpaid contractual principal balance |  | 36,683,000 us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Impaired loans, recorded principal balance |  | 33,240,000 us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Impaired loans, related allowance |  | 11,260,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Impaired loans, average recorded principal balance |  | 46,806,000 us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Retail Loan [Member] |  |
Financing Receivable, Impaired [Line Items] |  |
Impaired loans with no related allowance recorded, related allowance |  | 1,126,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember
Commercial: |  |
Impaired loans, related allowance |  | 1,126,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember
Total impaired loans: |  |
Impaired loans, unpaid contractual principal balance |  | 4,373,000 us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember
Impaired loans, recorded principal balance |  | 3,628,000 us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember
Impaired loans, related allowance |  | 1,126,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember
Impaired loans, average recorded principal balance |  | $ 3,155,000 us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember

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- Definition Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5212-111524 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5258-111524 + Details
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