Cover - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Mar. 13, 2024	Jun. 30, 2023
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-35845
Entity Registrant Name	LUMENT FINANCE TRUST, INC.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	45-4966519
Entity Address, Address Line One	230 Park Avenue
Entity Address, Address Line Two	20th Floor
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10169
City Area Code	212
Local Phone Number	317-5700
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 52.3
Entity Common Stock, Shares Outstanding		52,248,631
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Entity Central Index Key	0001547546
Common Stock
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	LFT
Security Exchange Name	NYSE
Redeemable Preferred Stock
Entity Information [Line Items]
Title of 12(b) Security	7.875% Series A Cumulative Redeemable Preferred Stock, par value $0.01 per share
Trading Symbol	LFTPrA
Security Exchange Name	NYSE