Debt and Foreign Currency Transactions and Translations -- Additional Information (Details) - USD ($)						3 Months Ended			9 Months Ended	12 Months Ended
	Feb. 24, 2025	Dec. 13, 2023	Apr. 19, 2023	Jul. 16, 2021	Mar. 03, 2015	Mar. 31, 2025		Mar. 31, 2024	Sep. 30, 2024	Dec. 31, 2023		Dec. 31, 2024	Dec. 23, 2024	Dec. 22, 2024	Oct. 17, 2024	Nov. 02, 2023	Apr. 04, 2019	Apr. 04, 2018
Debt Instrument [Line Items]
Aggregate principal amount						$ 2,496,000,000				$ 2,447,000,000
Interest Rate						6.83%		7.65%
MFIC Bethesda CLO 1 LLC Debt Securitization
Debt Instrument [Line Items]
Term debt securitization																$ 402,360,000
MFIC Bethesda CLO 2 LLC Debt Securitization
Debt Instrument [Line Items]
Aggregate principal amount						$ 529,600,000
Term debt securitization	$ 529,600,000
Senior Secured Facility
Debt Instrument [Line Items]
Required assets coverage percentage																	150.00%	200.00%
Final Maturity Date						Oct. 17, 2029				Oct. 17, 2029
Aggregate principal amount						$ 1,660,000,000	[1]			$ 1,660,000,000	[2]
Date of first required payment to repay						Oct. 17, 2028
Frequency of payment and payment terms						Commencing October 17, 2028, the Company is required to repay, the outstanding amount under the Senior Secured Facility as of October 17, 2028
Commitment fee per annum						0.375%
Base amount considered for covenants									$ 1,000,000,000
Considered percentage of net proceeds from sale of equity interest for covenants									25.00%
Credit facility expiration date			Oct. 17, 2029
Maximum borrowing capacity						$ 1,660,000,000						$ 1,660,000,000	$ 1,660,000,000	$ 1,815,000,000	$ 1,705,000,000
Maximum borrowing capacity under accordian feature						2,722,500,000
Available remaining capacity						$ 547,803,000						682,024,000
2025 Notes
Debt Instrument [Line Items]
Final Maturity Date					Mar. 03, 2025					Mar. 03, 2025
Aggregate principal amount					$ 350,000,000					$ 350,000,000
Date of first required payment to repay					Sep. 03, 2015
Frequency of payment and payment terms						The 2025 Notes will mature on March 3, 2025. Interest on the 2025 Notes is due semi-annually on March 3 and September 3, at an annual rate of 5.25%, commencing on September 3, 2015.
Frequency of periodic payment					semi-annually
Net proceeds from senior unsecured notes					$ 343,650,000
Annual interest rate					5.25%
2026 Notes
Debt Instrument [Line Items]
Final Maturity Date				Jul. 16, 2026		Jul. 16, 2026				Jul. 16, 2026
Aggregate principal amount				$ 125,000,000		$ 125,000,000				$ 125,000,000
Date of first required payment to repay				Jan. 16, 2022
Frequency of payment and payment terms						The 2026 Notes will mature on July 16, 2026. Interest on the 2026 Notes is due semi-annually on January 16 and July 16, at an annual rate of 4.50%, commencing on January 16, 2022.
Frequency of periodic payment				semi-annually
Net proceeds from senior unsecured notes				$ 122,965,000
Annual interest rate				4.50%
2028 Notes
Debt Instrument [Line Items]
Final Maturity Date		Dec. 15, 2028				Dec. 15, 2028				Dec. 15, 2028
Aggregate principal amount		$ 80,000,000				$ 80,000,000				$ 80,000,000
Redemption period, start date		Dec. 15, 2025
Debt instrument redemption rate per note		$ 25,000
Frequency of payment and payment terms						The 2028 Notes will mature on December 15, 2028. The 2028 Notes bear interest at a rate of 8.00% per year, commencing December 13, 2023.
Annual interest rate		8.00%
2028 Notes | Over-allotment Option
Debt Instrument [Line Items]
Aggregate principal amount		$ 5,000,000
Class A1 Senior Secured Floating Rate Notes Due Two Thousand Thirty Seven | MFIC Bethesda CLO 2 LLC Debt Securitization
Debt Instrument [Line Items]
Aggregate principal amount						$ 304,500,000
Term debt securitization	$ 304,500,000
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]	SOFR					SOFR
Borrowing base interest rate	1.48%
DebtInstrument maturity year	2037
Credit Rating	AAA(sf)					AAA/AAA
Debt Instrument interest rate description	three-month SOFR plus
Interest Rate						1.48%
Class A2 Senior Secured Floating Rate Notes Due Two Thousand Thirty Seven | MFIC Bethesda CLO 2 LLC Debt Securitization
Debt Instrument [Line Items]
Aggregate principal amount						$ 21,000,000
Term debt securitization	$ 21,000,000
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]	SOFR					SOFR
Borrowing base interest rate	1.70%
DebtInstrument maturity year	2037
Credit Rating	AAA(sf)					AAA/NR
Debt Instrument interest rate description	three-month SOFR plus
Interest Rate						1.70%
Class B Senior Secured Floating Rate Notes due 2037 | MFIC Bethesda CLO 2 LLC Debt Securitization
Debt Instrument [Line Items]
Aggregate principal amount						$ 31,500,000
Term debt securitization	$ 31,500,000
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]	SOFR					SOFR
DebtInstrument maturity year	2037
Credit Rating	AA(sf)					AA/NR
Debt Instrument interest rate description	three-month SOFR plus
Interest Rate	1.85%					1.85%
Class C Senior Secured Floating Rate Notes due 2037 | MFIC Bethesda CLO 2 LLC Debt Securitization
Debt Instrument [Line Items]
Aggregate principal amount						$ 42,000,000
Term debt securitization	$ 42,000,000
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]	SOFR					SOFR
DebtInstrument maturity year	2037
Credit Rating	A(sf)					A/NR
Debt Instrument interest rate description	three-month SOFR plus
Interest Rate	2.30%					2.30%
Class D Senior Secured Floating Rate Notes due 2037 | MFIC Bethesda CLO 2 LLC Debt Securitization
Debt Instrument [Line Items]
Aggregate principal amount						$ 31,500,000
Term debt securitization	$ 31,500,000
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]	SOFR					SOFR
DebtInstrument maturity year	2037
Credit Rating						BBB-/NR
Debt Instrument interest rate description	three-month SOFR plus
Interest Rate	3.75%					3.75%
Subordinated notes due 2125 | MFIC Bethesda CLO 2 LLC Debt Securitization
Debt Instrument [Line Items]
Aggregate principal amount	$ 99,100					$ 99,100,000
DebtInstrument maturity year	2125
Maximum | Senior Secured Facility
Debt Instrument [Line Items]
Fronting fees on letters of credit issued						0.25%
Maximum | Senior Secured Facility | SOFR
Debt Instrument [Line Items]
Borrowing base interest rate						1.85%
Maximum | Senior Secured Facility | Alternate Base Rate
Debt Instrument [Line Items]
Borrowing base interest rate						0.875%
Minimum | Senior Secured Facility
Debt Instrument [Line Items]
Required indebtedness ratio for covenants									1.5
Minimum | Senior Secured Facility | SOFR
Debt Instrument [Line Items]
Borrowing base interest rate						1.975%
Minimum | Senior Secured Facility | Alternate Base Rate
Debt Instrument [Line Items]
Borrowing base interest rate						0.75%
Standby Letters of Credit | Senior Secured Facility
Debt Instrument [Line Items]
Maximum borrowing capacity									$ 150,000,000
Line of credit						$ 6,215,000						$ 7,828,000

[1] Between October 17, 2024 and December 22, 2024, total lender commitments were $1,815,000. As of March 31, 2025, total lender commitments were $1,660,000.

[2] Between October 17, 2024 and December 22, 2024, total lender commitments were $1,815,000. As of December 31, 2024, total lender commitments were $1,660,000.