Commitments and Contingencies - Schedule of Future Minimum Payments Under Employment Agreements (Detail)	Dec. 31, 2020 USD ($)
Commitments And Contingencies [Abstract]
2021	$ 3,965,000
2022	3,081,000
2023	2,073,000
2024	2,073,000
2025	864,000
Total	$ 12,056,000

Employment agreements future minimum payments due in three years.

No definition available.

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