XML 72 R63.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Note 9 - Commitments and Off-balance-sheet Risk (Details) - Exposure to Credit Losses (USD $) | Mar. 31, 2015 | Dec. 31, 2014
--- | --- | ---
Note 9 - Commitments and Off-balance-sheet Risk (Details) - Exposure to Credit Losses [Line Items] |  |
Contractual amounts of financial instruments with off-balance sheet risk | $ 763,190,000 us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability | $ 781,748,000 us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability
Commercial Portfolio Segment [Member] | Unused lines of Credit [Member] |  |
Note 9 - Commitments and Off-balance-sheet Risk (Details) - Exposure to Credit Losses [Line Items] |  |
Contractual amounts of financial instruments with off-balance sheet risk | 518,801,000 us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability / us-gaap_FinancialInstrumentAxis = us-gaap_UnusedLinesOfCreditMember / us-gaap_FinancingReceivablePortfolioSegmentAxis = us-gaap_CommercialPortfolioSegmentMember | 554,856,000 us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability / us-gaap_FinancialInstrumentAxis = us-gaap_UnusedLinesOfCreditMember / us-gaap_FinancingReceivablePortfolioSegmentAxis = us-gaap_CommercialPortfolioSegmentMember
1-4 Family Mortgages [Member] | Unused lines of Credit [Member] |  |
Note 9 - Commitments and Off-balance-sheet Risk (Details) - Exposure to Credit Losses [Line Items] |  |
Contractual amounts of financial instruments with off-balance sheet risk | 62,029,000 us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability / us-gaap_FinancialInstrumentAxis = us-gaap_UnusedLinesOfCreditMember / us-gaap_FinancingReceivablePortfolioSegmentAxis = mbwm_OneToFourFamilyMortgagesMember | 60,983,000 us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability / us-gaap_FinancialInstrumentAxis = us-gaap_UnusedLinesOfCreditMember / us-gaap_FinancingReceivablePortfolioSegmentAxis = mbwm_OneToFourFamilyMortgagesMember
Consumer Portfolio Segment [Member] | Unused lines of Credit [Member] |  |
Note 9 - Commitments and Off-balance-sheet Risk (Details) - Exposure to Credit Losses [Line Items] |  |
Contractual amounts of financial instruments with off-balance sheet risk | 12,085,000 us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability / us-gaap_FinancialInstrumentAxis = us-gaap_UnusedLinesOfCreditMember / us-gaap_FinancingReceivablePortfolioSegmentAxis = us-gaap_ConsumerPortfolioSegmentMember | 11,649,000 us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability / us-gaap_FinancialInstrumentAxis = us-gaap_UnusedLinesOfCreditMember / us-gaap_FinancingReceivablePortfolioSegmentAxis = us-gaap_ConsumerPortfolioSegmentMember
Consumer Other Financing Receivable 1 [Member] | Unused lines of Credit [Member] |  |
Note 9 - Commitments and Off-balance-sheet Risk (Details) - Exposure to Credit Losses [Line Items] |  |
Contractual amounts of financial instruments with off-balance sheet risk | 7,681,000 us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability / us-gaap_FinancialInstrumentAxis = us-gaap_UnusedLinesOfCreditMember / us-gaap_FinancingReceivablePortfolioSegmentAxis = mbwm_ConsumerOtherFinancingReceivable1Member | 8,673,000 us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability / us-gaap_FinancialInstrumentAxis = us-gaap_UnusedLinesOfCreditMember / us-gaap_FinancingReceivablePortfolioSegmentAxis = mbwm_ConsumerOtherFinancingReceivable1Member
Loan Origination Commitments [Member] |  |
Note 9 - Commitments and Off-balance-sheet Risk (Details) - Exposure to Credit Losses [Line Items] |  |
Contractual amounts of financial instruments with off-balance sheet risk | 131,561,000 us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability / us-gaap_FinancialInstrumentAxis = us-gaap_LoanOriginationCommitmentsMember | 110,126,000 us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability / us-gaap_FinancialInstrumentAxis = us-gaap_LoanOriginationCommitmentsMember
Standby Letters of Credit [Member] |  |
Note 9 - Commitments and Off-balance-sheet Risk (Details) - Exposure to Credit Losses [Line Items] |  |
Contractual amounts of financial instruments with off-balance sheet risk | $ 31,033,000 us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability / us-gaap_CreditFacilityAxis = us-gaap_StandbyLettersOfCreditMember | $ 35,461,000 us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability / us-gaap_CreditFacilityAxis = us-gaap_StandbyLettersOfCreditMember

X
- Details
Name: | mbwm_Note9CommitmentsandOffbalancesheetRiskDetailsExposuretoCreditLossesLineItems
Namespace Prefix: | mbwm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The fair value of financial liabilities, which are not recognized in the financial statements (off-balance sheet) because they fail to meet some other criterion for recognition. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13433-108611 + Details
Name: | us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_CreditFacilityAxis=us-gaap_StandbyLettersOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_LoanOriginationCommitmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=mbwm_ConsumerOtherFinancingReceivable1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=mbwm_OneToFourFamilyMortgagesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |