USE OF SPECIAL PURPOSE ENTITIES AND VARIABLE INTEREST ENTITIES - Summary of Loan and Borrowing Characteristics (Details)		3 Months Ended	12 Months Ended
		Mar. 31, 2025 USD ($) contract instrument mortgageLoan	Dec. 31, 2024 USD ($) instrument mortgageLoan contract
Variable Interest Entity [Line Items]
Collateralized loan obligations and secured financings	[1]	$ 772,285,071	$ 828,390,189
One month SOFR rate ( as a percent)		4.31%	4.51%
Weighted average LIBOR floor rate (as a percent)		0.94%	0.63%
SOFR spread rate (as a percent)		3.55%	3.53%
Basis spread on one-month LIBOR (percent)		2.26%
30-Day SOFR
Variable Interest Entity [Line Items]
30-day SOFR rate		0.0432	0.0440
Commercial Real Estate Portfolio Segment
Variable Interest Entity [Line Items]
Collateral (loan investments) (Count) | mortgageLoan		61	65
Carrying Value		$ 1,005,841,618	$ 1,060,123,298
Net of purchase discounts		$ 2,978,218	$ 3,466,214
2021-FL1 CLO and LMF 2023-1
Variable Interest Entity [Line Items]
Financings provided, (Count) | instrument		2	2
Collateralized loan obligations and secured financings		$ 772,285,071	$ 828,390,189
2021-FL1 CLO and LMF 2023-1 | Secured Overnight Financing Rate (SOFR)
Variable Interest Entity [Line Items]
Weighted average yield (percent)		7.86%	8.08%
Weighted average yield (percent)		6.58%	6.66%
2021-FL1 CLO and LMF 2023-1 | Commercial Real Estate Portfolio Segment
Variable Interest Entity [Line Items]
Collateral (loan investments) (Count) | contract		61	65
Principal Value | 2021-FL1 CLO and LMF 2023-1
Variable Interest Entity [Line Items]
Carrying Value		$ 1,010,888,938	$ 1,065,563,646
Collateralized loan obligations and secured financings		774,342,955	830,698,696
Principal Value | LFT CRE 2021-FL1, Ltd.
Variable Interest Entity [Line Items]
Net of purchase discounts		3,076,726	3,577,207
Carrying Value | 2021-FL1 CLO and LMF 2023-1
Variable Interest Entity [Line Items]
Carrying Value		989,668,838	1,049,886,009
Collateralized loan obligations and secured financings		772,285,071	828,390,189
Carrying Value | LMF 2023-1 Financing
Variable Interest Entity [Line Items]
Debt issuance costs		$ 2,057,885	$ 2,308,507

[1] Our consolidated balance sheets include assets and liabilities of consolidated variable interest entities ("VIEs") as the Company was the primary beneficiary of these VIEs. As of March 31, 2025 and December 31, 2024, assets of consolidated VIEs totaled $996,233,424 and $1,058,138,406, respectively and the liabilities of consolidated VIEs totaled $774,692,458 and $831,001,605 respectively. See Note 4 for further discussion.