Amount retained by the Bank.

No definition available.

Name:	mfin_AmountRetainedByBank
Namespace Prefix:	mfin_
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Balance Type:	debit
Period Type:	instant

- Definition

Loan participation pool.

+ References

No definition available.

+ Details

Name:	mfin_LoanParticipationPool
Namespace Prefix:	mfin_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Sale of recreation loans.

+ References

No definition available.

+ Details

Name:	mfin_SaleOfRecreationLoans
Namespace Prefix:	mfin_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Senior unsecured notes.

+ References

No definition available.

+ Details

Name:	mfin_SeniorUnsecuredNotes
Namespace Prefix:	mfin_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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- Definition

Date when the debt instrument is scheduled to be fully repaid, in YYYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition

Amount, before valuation allowance, of financing receivable classified as held-for-sale.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cash inflow resulting from the sale of loans classified as held-for-sale, including proceeds from loans sold through mortgage securitization.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
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Period Type:	duration

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Details

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Subsequent Events - Additional Information (Detail) - USD ($) $ in Thousands			3 Months Ended
	Apr. 30, 2026	Apr. 28, 2026	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Subsequent Event [Line Items]
Loans held for sale			$ 10,786		$ 15,144
Proceeds from sale of loans held for sale			$ 174,342	$ 133,127
Subsequent Event [Member]
Subsequent Event [Line Items]
Aggregate principal amount of senior unsecured notes		$ 75,000
Maturity date		May 01, 2031
Interest Rate		8.25%
Subsequent Event [Member] \| Recreation Loan
Subsequent Event [Line Items]
Sale of recreation loans	$ 47,000
Proceeds from sale of loans held for sale	50,000
Loan participation pool	52,200
Amount retained by the Bank	$ 5,200