COMMERCIAL MORTGAGE LOANS HELD-FOR-INVESTMENT - Summary of Commercial Mortgage Loans (Details)	9 Months Ended
Sep. 30, 2018 USD ($) mortgage_loan	Dec. 31, 2017 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial mortgage loans held-for-investment, at amortized cost	$ 544,586,537	$ 0
Commercial real estate portfolio segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	544,586,537	0
Commercial mortgage loans held-for-investment, at amortized cost	544,586,537	$ 0
Carrying Value	$ 544,586,537
Number of Loans \| mortgage_loan	43
Weighted average, floating rate loan, percentage	100.00%
Weighted average coupon rate, percentage	6.50%
Weighted average, life (in years)	3 years 10 months 24 days
Outstanding senior secured loans from loan participations	$ 4,054,577
Commercial real estate portfolio segment \| Hunt CMT
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial mortgage loans held-for-investment, at amortized cost	$ 540,531,960

Financing Receivable, Coupon Rate

No definition available.

Name:	oaks_FinancingReceivableCouponRate
Namespace Prefix:	oaks_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Financing Receivable, Floating Rate, Percentage

+ References

No definition available.

+ Details

Name:	oaks_FinancingReceivableFloatingRatePercentage
Namespace Prefix:	oaks_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Financing Receivable, Number Of Loans

+ References

No definition available.

+ Details

Name:	oaks_FinancingReceivableNumberOfLoans
Namespace Prefix:	oaks_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Financing Receivable, Outstanding, Face Amount

+ References

No definition available.

+ Details

Name:	oaks_FinancingReceivableOutstandingFaceAmount
Namespace Prefix:	oaks_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Financing Receivable, Outstanding Loan Participants

+ References

No definition available.

+ Details

Name:	oaks_FinancingReceivableOutstandingLoanParticipants
Namespace Prefix:	oaks_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Financing Receivable, Weighted Average Life

+ References

No definition available.

+ Details

Name:	oaks_FinancingReceivableWeightedAverageLife
Namespace Prefix:	oaks_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

+ Details

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

- Definition

Net amount of the investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, credit card receivables, notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets. Excludes trade accounts receivable with contractual maturity of one year or less and arose from the sale of goods or services.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.3)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Details

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

- Details

Name:	us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis=oaks_HuntCMTEquityLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: