XML 69 R56.htm IDEA: XBRL DOCUMENT
v3.25.3

Note 7 - Loans and Related Allowance for Credit Losses - Troubled Debt Restructurings Past Due (Details) - USD ($) $ in Thousands | Sep. 30, 2025 | Sep. 30, 2024
--- | --- | ---
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | $ 7,088 | $ 15,302
Financial Asset, Not Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 7,088 | 15,302
Financial Asset, 30 to 59 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 | 0
Financial Asset, 60 to 89 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 | 0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 | 0
Financial Asset, Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 | 0
Commercial Real Estate Portfolio Segment [Member] | Owner Occupied Loan [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 2,224 |
Commercial Real Estate Portfolio Segment [Member] | Owner Occupied Loan [Member] | Financial Asset, Not Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 2,224 |
Commercial Real Estate Portfolio Segment [Member] | Owner Occupied Loan [Member] | Financial Asset, 30 to 59 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 |
Commercial Real Estate Portfolio Segment [Member] | Owner Occupied Loan [Member] | Financial Asset, 60 to 89 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 |
Commercial Real Estate Portfolio Segment [Member] | Owner Occupied Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 |
Commercial Real Estate Portfolio Segment [Member] | Owner Occupied Loan [Member] | Financial Asset, Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 |
Commercial Real Estate Portfolio Segment [Member] | Non-owner occupied Loan [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 1,763 | 13,483
Commercial Real Estate Portfolio Segment [Member] | Non-owner occupied Loan [Member] | Financial Asset, Not Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 1,763 | 13,483
Commercial Real Estate Portfolio Segment [Member] | Non-owner occupied Loan [Member] | Financial Asset, 30 to 59 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 | 0
Commercial Real Estate Portfolio Segment [Member] | Non-owner occupied Loan [Member] | Financial Asset, 60 to 89 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 | 0
Commercial Real Estate Portfolio Segment [Member] | Non-owner occupied Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 | 0
Commercial Real Estate Portfolio Segment [Member] | Non-owner occupied Loan [Member] | Financial Asset, Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 | 0
Construction and Other [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 2,055 | 1,819
Construction and Other [Member] | Financial Asset, Not Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 2,055 | 1,819
Construction and Other [Member] | Financial Asset, 30 to 59 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 | 0
Construction and Other [Member] | Financial Asset, 60 to 89 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 | 0
Construction and Other [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 | 0
Construction and Other [Member] | Financial Asset, Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 | $ 0
Residential Portfolio Segment [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 57 |
Residential Portfolio Segment [Member] | Financial Asset, Not Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 57 |
Residential Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 |
Residential Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 |
Residential Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 |
Residential Portfolio Segment [Member] | Financial Asset, Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 |
Commercial And Industrial [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 889 |
Commercial And Industrial [Member] | Financial Asset, Not Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 889 |
Commercial And Industrial [Member] | Financial Asset, 30 to 59 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 |
Commercial And Industrial [Member] | Financial Asset, 60 to 89 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 |
Commercial And Industrial [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 |
Commercial And Industrial [Member] | Financial Asset, Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 |
Home Equity Lines of Credit [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 100 |
Home Equity Lines of Credit [Member] | Financial Asset, Not Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 100 |
Home Equity Lines of Credit [Member] | Financial Asset, 30 to 59 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 |
Home Equity Lines of Credit [Member] | Financial Asset, 60 to 89 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 |
Home Equity Lines of Credit [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | 0 |
Home Equity Lines of Credit [Member] | Financial Asset, Past Due [Member] |  |
Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months | $ 0 |

X
- Definition Amortized cost excluding accrued interest, of financing receivable 12 months after modification for debtor experiencing financial difficulty. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 42 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-42 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestModifiedPast12Months
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancialAssetNotPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables30To59DaysPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables60To89DaysPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancialAssetPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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

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

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

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