XML 146 R69.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Note 4 - Loans and Allowance for Loan Losses (Details) - Components of Loan Portfolio (USD $) | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | $ 2,089,277,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome | $ 1,053,243,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome | $ 1,041,189,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Loans, percentage of portfolio | 100.00%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan | 100.00%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan |
Loans, percentage of change in loans | 98.40%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage |  |
Originated Loan [Member] | Commercial and Industrial [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 384,570,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember | 286,373,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Loans, percentage of portfolio | 30.80%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember | 27.20%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Loans, percentage of change in loans | 34.30%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |  |
Originated Loan [Member] | Commercial Vacant Land and Land Development and Residential Construction Loan [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 29,826,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember | 36,741,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Loans, percentage of portfolio | 2.40%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember | 3.50%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Loans, percentage of change in loans | (18.80%)mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |  |
Originated Loan [Member] | Commercial Real Estate Owner Occupied Loan [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 291,758,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember | 261,877,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Loans, percentage of portfolio | 23.40%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember | 24.90%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Loans, percentage of change in loans | 11.40%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |  |
Originated Loan [Member] | Commercial Real Estate Non Owner Occupied Loan [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 410,977,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember | 364,066,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Loans, percentage of portfolio | 33.00%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember | 34.60%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Loans, percentage of change in loans | 12.90%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |  |
Originated Loan [Member] | Commercial Real Estate Multi Family and Residential Rental Loan [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 36,058,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember | 37,639,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Loans, percentage of portfolio | 2.90%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember | 3.50%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Loans, percentage of change in loans | (4.20%)mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |  |
Originated Loan [Member] | Commercial Portfolio Segment [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 1,153,189,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 986,696,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Loans, percentage of portfolio | 92.50%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 93.70%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Loans, percentage of change in loans | 16.90%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |  |
Originated Loan [Member] | Retail Home Equity and Other [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 50,059,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember | 35,080,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Loans, percentage of portfolio | 4.00%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember | 3.30%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Loans, percentage of change in loans | 42.70%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |  |
Originated Loan [Member] | Retail 1-4 Family Mortgages [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 42,868,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember | 31,467,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Loans, percentage of portfolio | 3.50%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember | 3.00%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Loans, percentage of change in loans | 36.20%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |  |
Originated Loan [Member] | Retail Loan [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 92,927,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember | 66,547,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Loans, percentage of portfolio | 7.50%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember | 6.30%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Loans, percentage of change in loans | 39.60%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |  |
Originated Loan [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 1,246,116,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember | 1,053,243,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember |
Loans, percentage of portfolio | 100.00%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember | 100.00%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember |
Loans, percentage of change in loans | 18.30%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancialInstrumentAxis = mbwm_OriginatedLoanMember |  |
Acquired Loan [Member] | Commercial and Industrial [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 166,037,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember | 0 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Loans, percentage of portfolio | 19.70%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |  |
Loans, percentage of change in loans |  |  |
Acquired Loan [Member] | Commercial Vacant Land and Land Development and Residential Construction Loan [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 22,148,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember | 0 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Loans, percentage of portfolio | 2.60%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |  |
Loans, percentage of change in loans |  |  |
Acquired Loan [Member] | Commercial Real Estate Owner Occupied Loan [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 138,630,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember | 0 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Loans, percentage of portfolio | 16.40%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |  |
Loans, percentage of change in loans |  |  |
Acquired Loan [Member] | Commercial Real Estate Non Owner Occupied Loan [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 148,597,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember | 0 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Loans, percentage of portfolio | 17.60%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |  |
Loans, percentage of change in loans |  |  |
Acquired Loan [Member] | Commercial Real Estate Multi Family and Residential Rental Loan [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 86,702,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember | 0 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Loans, percentage of portfolio | 10.30%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |  |
Loans, percentage of change in loans |  |  |
Acquired Loan [Member] | Commercial Portfolio Segment [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 562,114,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 0 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Loans, percentage of portfolio | 66.60%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |  |
Loans, percentage of change in loans |  |  |
Acquired Loan [Member] | Retail Home Equity and Other [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 109,219,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember | 0 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Loans, percentage of portfolio | 13.00%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |  |
Loans, percentage of change in loans |  |  |
Acquired Loan [Member] | Retail 1-4 Family Mortgages [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 171,828,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember | 0 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Loans, percentage of portfolio | 20.40%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |  |
Loans, percentage of change in loans |  |  |
Acquired Loan [Member] | Retail Loan [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 281,047,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember | 0 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Loans, percentage of portfolio | 33.40%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |  |
Loans, percentage of change in loans |  |  |
Acquired Loan [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 843,161,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember | 0 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |
Loans, percentage of portfolio | 100.00%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancialInstrumentAxis = mbwm_AcquiredLoanMember |  |
Loans, percentage of change in loans |  |  |
Commercial and Industrial [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 550,607,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember | 286,373,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Loans, percentage of portfolio | 26.40%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember | 27.20%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |
Loans, percentage of change in loans | 92.30%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialAndIndustrialMember |  |
Commercial Vacant Land and Land Development and Residential Construction Loan [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 51,974,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember | 36,741,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Loans, percentage of portfolio | 2.50%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember | 3.50%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |
Loans, percentage of change in loans | 41.50%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialVacantLandAndLandDevelopmentAndResidentialConstructionLoanMember |  |
Commercial Real Estate Owner Occupied Loan [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 430,388,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember | 261,877,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Loans, percentage of portfolio | 20.50%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember | 24.90%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |
Loans, percentage of change in loans | 64.30%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateOwnerOccupiedLoanMember |  |
Commercial Real Estate Non Owner Occupied Loan [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 559,574,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember | 364,066,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Loans, percentage of portfolio | 26.80%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember | 34.60%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |
Loans, percentage of change in loans | 53.70%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateNonOwnerOccupiedLoanMember |  |
Commercial Real Estate Multi Family and Residential Rental Loan [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 122,760,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember | 37,639,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Loans, percentage of portfolio | 5.90%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember | 3.50%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |
Loans, percentage of change in loans | 226.20%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_CommercialRealEstateMultiFamilyAndResidentialRentalLoanMember |  |
Commercial Portfolio Segment [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 1,715,303,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 986,696,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 968,506,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Loans, percentage of portfolio | 82.10%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 93.70%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |
Loans, percentage of change in loans | 73.80%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember |  |
Retail Home Equity and Other [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 159,278,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember | 35,080,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Loans, percentage of portfolio | 7.60%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember | 3.30%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |
Loans, percentage of change in loans | 354.00%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailHomeEquityAndOtherMember |  |
Retail 1-4 Family Mortgages [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | 214,696,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember | 31,467,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Loans, percentage of portfolio | 10.30%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember | 3.00%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |
Loans, percentage of change in loans | 582.30%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_Retail1To4FamilyMortgagesMember |  |
Retail Loan [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans (in Dollars) | $ 373,974,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember | $ 66,547,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember | $ 72,683,000 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember
Loans, percentage of portfolio | 17.90%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember | 6.30%mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |
Loans, percentage of change in loans | 462.00%mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = mbwm_RetailLoanMember |  |

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- Definition Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5074-111524 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522 + Details
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