XML 51 R38.htm IDEA: XBRL DOCUMENT
v3.25.3

Note 5 - Fair Value Measurements (Details Textual) - USD ($) | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Dec. 31, 2024
Estimated Selling Costs of Impaired Loans | $ 1,800,000 | $ 53,000 | $ 968,000
Mandatorily Redeemable Securities | $ 8,000,000 |  |
Notes Payable, Other Payables [Member] |  |  |
Debt Instrument, Basis Spread on Variable Rate | 1.67% |  |
Other Borrowings [Member] |  |  |
Notes Payable, Total | $ 8,200,000 |  |

X
- Definition The estimated amount of selling costs that would incur when impaired loans sold. + References No definition available. + Details
Name: | mbcn_EstimatedSellingCostsOfImpairedLoans
Namespace Prefix: | mbcn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of mandatorily redeemable securities. + References No definition available. + Details
Name: | mbcn_MandatorilyRedeemableSecurities
Namespace Prefix: | mbcn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -SubTopic 10 -Topic 210 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)(a)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(17)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 + Details
Name: | us-gaap_NotesPayable
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_NotesPayableOtherPayablesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=mbcn_OtherBorrowingsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |