XML 50 R40.htm IDEA: XBRL DOCUMENT
v3.20.2

Note 3 - Loans and Allowance for Loan Losses - Impaired Loans (Details) - USD ($) | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2020 | Jun. 30, 2019 | Jun. 30, 2020 | Jun. 30, 2019 | Dec. 31, 2019
With no related allowance recorded, unpaid principal balance | $ 19,722,000 |  | $ 19,722,000 |  | $ 13,687,000
With no related allowance recorded, principal balance | 17,451,000 |  | 17,451,000 |  | 12,245,000
With no related allowance recorded, average recorded principal balance | 18,016,000 | $ 16,212,000 | 16,092,000 | $ 15,518,000 |
With related allowance recorded, unpaid principal balance | 2,809,000 |  | 2,809,000 |  | 2,398,000
With related allowance recorded, principal balance | 2,789,000 |  | 2,789,000 |  | 2,377,000
Related allowance | 1,512,000 |  | 1,512,000 |  | 1,623,000
With related allowance recorded, average recorded principal balance | 3,278,000 | 12,394,000 | 2,978,000 | 11,568,000 |
Total unpaid principal balance | 22,531,000 |  | 22,531,000 |  | 16,085,000
Total principal balance | 20,240,000 |  | 20,240,000 |  | 14,622,000
Total average recorded principal balance | 21,294,000 | 28,606,000 | 19,070,000 | 27,086,000 |
Commercial Portfolio Segment [Member] |  |  |  |  |
With no related allowance recorded, unpaid principal balance | 13,802,000 |  | 13,802,000 |  | 9,136,000
With no related allowance recorded, principal balance | 13,606,000 |  | 13,606,000 |  | 9,068,000
With no related allowance recorded, average recorded principal balance | 14,116,000 | 12,651,000 | 12,433,000 | 12,082,000 |
With related allowance recorded, unpaid principal balance | 1,551,000 |  | 1,551,000 |  | 1,538,000
With related allowance recorded, principal balance | 1,550,000 |  | 1,550,000 |  | 1,536,000
Related allowance | 1,011,000 |  | 1,011,000 |  | 1,184,000
With related allowance recorded, average recorded principal balance | 2,154,000 | 11,183,000 | 1,948,000 | 10,233,000 |
Total unpaid principal balance | 15,353,000 |  | 15,353,000 |  | 10,674,000
Total principal balance | 15,156,000 |  | 15,156,000 |  | 10,604,000
Total average recorded principal balance | 16,270,000 | 23,834,000 | 14,381,000 | 22,315,000 |
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] |  |  |  |  |
With no related allowance recorded, unpaid principal balance | 8,784,000 |  | 8,784,000 |  | 8,129,000
With no related allowance recorded, principal balance | 8,753,000 |  | 8,753,000 |  | 8,129,000
With no related allowance recorded, average recorded principal balance | 9,460,000 | 10,214,000 | 9,016,000 | 9,810,000 |
With related allowance recorded, unpaid principal balance | 1,331,000 |  | 1,331,000 |  | 460,000
With related allowance recorded, principal balance | 1,330,000 |  | 1,330,000 |  | 458,000
Related allowance | 1,006,000 |  | 1,006,000 |  | 202,000
With related allowance recorded, average recorded principal balance | 1,751,000 | 9,687,000 | 1,320,000 | 8,184,000 |
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] |  |  |  |  |
With no related allowance recorded, unpaid principal balance | 538,000 |  | 538,000 |  | 85,000
With no related allowance recorded, principal balance | 453,000 |  | 453,000 |  | 85,000
With no related allowance recorded, average recorded principal balance | 326,000 | 90,000 | 246,000 | 91,000 |
With related allowance recorded, unpaid principal balance | 0 |  | 0 |  | 0
With related allowance recorded, principal balance | 0 |  | 0 |  | 0
Related allowance | 0 |  | 0 |  | 0
With related allowance recorded, average recorded principal balance | 192,000 | 0 | 128,000 | 0 |
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] |  |  |  |  |
With no related allowance recorded, unpaid principal balance | 4,434,000 |  | 4,434,000 |  | 715,000
With no related allowance recorded, principal balance | 4,375,000 |  | 4,375,000 |  | 667,000
With no related allowance recorded, average recorded principal balance | 4,316,000 | 2,083,000 | 3,100,000 | 1,996,000 |
With related allowance recorded, unpaid principal balance | 49,000 |  | 49,000 |  | 1,078,000
With related allowance recorded, principal balance | 49,000 |  | 49,000 |  | 1,078,000
Related allowance | 2,000 |  | 2,000 |  | 982,000
With related allowance recorded, average recorded principal balance | 126,000 | 1,384,000 | 443,000 | 1,858,000 |
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] |  |  |  |  |
With no related allowance recorded, unpaid principal balance | 25,000 |  | 25,000 |  | 178,000
With no related allowance recorded, principal balance | 25,000 |  | 25,000 |  | 178,000
With no related allowance recorded, average recorded principal balance | 12,000 | 175,000 | 67,000 | 117,000 |
With related allowance recorded, unpaid principal balance | 170,000 |  | 170,000 |  | 0
With related allowance recorded, principal balance | 170,000 |  | 170,000 |  | 0
Related allowance | 3,000 |  | 3,000 |  | 0
With related allowance recorded, average recorded principal balance | 85,000 | 47,000 | 57,000 | 101,000 |
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] |  |  |  |  |
With no related allowance recorded, unpaid principal balance | 21,000 |  | 21,000 |  | 29,000
With no related allowance recorded, principal balance | 0 |  | 0 |  | 9,000
With no related allowance recorded, average recorded principal balance | 2,000 | 89,000 | 4,000 | 68,000 |
With related allowance recorded, unpaid principal balance | 1,000 |  | 1,000 |  | 0
With related allowance recorded, principal balance | 1,000 |  | 1,000 |  | 0
Related allowance | 0 |  | 0 |  | 0
With related allowance recorded, average recorded principal balance | 0 | 65,000 | 0 | 90,000 |
Retail Portfolio Segment [Member] |  |  |  |  |
With no related allowance recorded, unpaid principal balance | 5,920,000 |  | 5,920,000 |  | 4,551,000
With no related allowance recorded, principal balance | 3,845,000 |  | 3,845,000 |  | 3,177,000
With no related allowance recorded, average recorded principal balance | 3,900,000 | 3,561,000 | 3,659,000 | 3,436,000 |
With related allowance recorded, unpaid principal balance | 1,258,000 |  | 1,258,000 |  | 860,000
With related allowance recorded, principal balance | 1,239,000 |  | 1,239,000 |  | 841,000
Related allowance | 501,000 |  | 501,000 |  | 439,000
With related allowance recorded, average recorded principal balance | 1,124,000 | 1,211,000 | 1,030,000 | 1,335,000 |
Total unpaid principal balance | 7,178,000 |  | 7,178,000 |  | 5,411,000
Total principal balance | 5,084,000 |  | 5,084,000 |  | 4,018,000
Total average recorded principal balance | 5,024,000 | 4,772,000 | 4,689,000 | 4,771,000 |
Retail Portfolio Segment [Member] | Home Equity and Other [Member] |  |  |  |  |
With no related allowance recorded, unpaid principal balance | 1,359,000 |  | 1,359,000 |  | 1,279,000
With no related allowance recorded, principal balance | 1,274,000 |  | 1,274,000 |  | 1,209,000
With no related allowance recorded, average recorded principal balance | 1,273,000 | 1,360,000 | 1,252,000 | 1,222,000 |
With related allowance recorded, unpaid principal balance | 596,000 |  | 596,000 |  | 502,000
With related allowance recorded, principal balance | 577,000 |  | 577,000 |  | 485,000
Related allowance | 339,000 |  | 339,000 |  | 356,000
With related allowance recorded, average recorded principal balance | 486,000 | 572,000 | 486,000 | 672,000 |
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member] |  |  |  |  |
With no related allowance recorded, unpaid principal balance | 4,561,000 |  | 4,561,000 |  | 3,272,000
With no related allowance recorded, principal balance | 2,571,000 |  | 2,571,000 |  | 1,968,000
With no related allowance recorded, average recorded principal balance | 2,627,000 | 2,201,000 | 2,407,000 | 2,214,000 |
With related allowance recorded, unpaid principal balance | 662,000 |  | 662,000 |  | 358,000
With related allowance recorded, principal balance | 662,000 |  | 662,000 |  | 356,000
Related allowance | 162,000 |  | 162,000 |  | $ 83,000
With related allowance recorded, average recorded principal balance | $ 638,000 | $ 639,000 | $ 544,000 | $ 663,000 |

X
- 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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition 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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953550-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of allowance for credit losses related to recorded investment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableRelatedAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of average investment of impaired financing receivables for which there is no related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of investment in impaired financing receivables for which there is no related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953550-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of average investment of impaired financing receivables for which there is a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of investment in impaired financing receivables for which there is a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953550-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbwm_CommercialAndIndustrialMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbwm_VacantLandAndLandDevelopmentAndResidentialConstructionLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbwm_RealEstateOwnerOccupiedLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbwm_RealEstateNonOwnerOccupiedLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbwm_RealEstateMultiFamilyAndResidentialRentalLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbwm_HomeEquityAndOtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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