COMMERCIAL MORTGAGE LOANS HELD-FOR-INVESTMENT - Loan Portfolio Activity (Details) - USD ($)	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021
Commercial Mortgage Loans Held-for-Investment
Purchases and fundings	$ 222,142,167	$ 338,386,251
Principal payments	(171,007,115)	(273,837,132)
Accretion of purchase discount	125,098	3,781
Amortization of purchase premium	(50,522)	$ (78,008)
Commercial Real Estate Portfolio Segment
Commercial Mortgage Loans Held-for-Investment
Balance at December 31, 2021	1,001,825,294
Purchases and fundings	222,142,167
Principal payments	(190,040,765)
Accretion of purchase discount	125,098
Amortization of purchase premium	(50,522)
Provision for loan losses	(351,914)
Balance at June 30, 2022	$ 1,033,649,358

Accretion of Discounts on Held-for-investment Loans

No definition available.

Name:	oaks_AccretionOfDiscountsOnHeldForInvestmentLoans
Namespace Prefix:	oaks_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Allowance For Loan Losses

+ References

No definition available.

+ Details

Name:	oaks_AllowanceForLoanLosses
Namespace Prefix:	oaks_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amortization of Premiums on Held-for-investment Loans

+ References

No definition available.

+ Details

Name:	oaks_AmortizationOfPremiumsOnHeldForInvestmentLoans
Namespace Prefix:	oaks_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Loans Receivable Held-For-Investment, Net, Reconciliation To Cash Flow [Roll Forward]

+ References

No definition available.

+ Details

Name:	oaks_LoansReceivableHeldForInvestmentNetReconciliationToCashFlowRollForward
Namespace Prefix:	oaks_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amortized cost, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919230-210447

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=124259787&loc=d3e4428-111522

+ Details

Name:	us-gaap_NotesReceivableNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cash outflow associated with purchasing loans held for investment purposes during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireLoansHeldForInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow from repayments of the balance excluding interest (principal) on loans receivable and leases held for investment purposes.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromPrincipalRepaymentsOnLoansAndLeasesHeldForInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: