Note 10 - Borrowed Funds (Details Textual) $ in Billions	Dec. 31, 2024 USD ($)
Borrowed Funds, Loans Pledged As Collateral	$ 1.6

Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered.

No definition available.

Name:	mnsb_BorrowedFundsLoansPledgedAsCollateral
Namespace Prefix:	mnsb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant