Debt and Foreign Currency Transactions and Translations - Summary of Secured and Unsecured Notes Issued (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Debt Instrument [Line Items]
Principal Outstanding		$ 1,518,176		$ 1,518,176		$ 1,469,977
Total Bethesda CLO 1 Notes		$ 1,511,552		$ 1,511,552		$ 1,462,267
Interest rate		7.49%	7.04%	7.55%	6.94%
MFIC Bethesda CLO 1 LLC Debt Securitization
Debt Instrument [Line Items]
Principal Outstanding		$ 248,000		$ 248,000
Subordinated Notes	[1]	154,360		154,360
Total Bethesda CLO 1 Notes		402,360		402,360
MFIC Bethesda CLO 1 LLC Debt Securitization | Class A-1 Notes
Debt Instrument [Line Items]
Principal Outstanding		232,000		$ 232,000
Interest rate				2.40%
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]				Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
Credit Rating				AAA(sf)/ AAAsf
MFIC Bethesda CLO 1 LLC Debt Securitization | Class A-2 Notes
Debt Instrument [Line Items]
Principal Outstanding	[1]	$ 16,000		$ 16,000
Interest rate	[1]			2.90%
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]				Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
Credit Rating	[1]			AAA(sf)

[1] The Company retained (in the Bethesda CLO 1 Depositor) all of the Class A-2 Notes and the Subordinated Notes issued in the Bethesda CLO 1 Debt Securitization which are eliminated in consolidation.