COMMERCIAL MORTGAGE LOANS HELD-FOR-INVESTMENT - Summary of Commercial Mortgage Loans (Details)	3 Months Ended	12 Months Ended
Mar. 31, 2019 USD ($) mortgage_loan	Dec. 31, 2018 USD ($) mortgage_loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial mortgage loans held-for-investment, at amortized cost	$ 585,770,803	$ 555,172,891
Commercial real estate portfolio segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	585,770,803	555,172,891
Commercial mortgage loans held-for-investment, at amortized cost	585,770,803	555,172,891
Carrying Value	$ 585,770,803	$ 555,172,891
Number of Loans \| mortgage_loan	45	44
Weighted average, floating rate loan, percentage	100.00%	100.00%
Weighted average coupon rate, percentage	6.50%	6.40%
Weighted average, life (in years)	4 years	4 years 1 month 6 days
Outstanding senior secured loans from loan participations	$ 3,892,119	$ 4,617,388
Commercial real estate portfolio segment \| Hunt CMT
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial mortgage loans held-for-investment, at amortized cost	$ 581,878,684	$ 550,555,503

Financing Receivable, Coupon Rate

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Financing Receivable, Floating Rate, Percentage

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Financing Receivable, Number Of Loans

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Financing Receivable, Outstanding, Face Amount

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Financing Receivable, Outstanding Loan Participants

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Financing Receivable, Weighted Average Life

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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.

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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

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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.

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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

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