FAIR VALUE OF FINANCIAL INSTRUMENTS - Fair Value of Financial Instruments Not Recorded at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Carrying Amount
Liabilities:
Mortgage payable	$ 96,946	$ 96,926
Junior subordinated notes	25,365	25,299
Carrying Amount \| SBA 7(a) loans receivable, subject to credit risk
Assets:
Loans receivable	31,911	26,149
Carrying Amount \| SBA 7(a) loans receivable, subject to loan-backed notes
Assets:
Loans receivable	24,232	27,595
Carrying Amount \| SBA 7(a) loans receivable, paycheck protection program
Assets:
Loans receivable	15,504	0
Carrying Amount \| SBA 7(a) loans receivable, subject to secured borrowings
Assets:
Loans receivable	8,925	12,682
Carrying Amount \| SBA 7(a) loans receivable, held for sale
Assets:
Loans receivable	8,742	1,653
Fair Value, Measurements, Nonrecurring \| Estimated Fair Value \| Level 3
Liabilities:
Mortgage payable	106,067	99,764
Junior subordinated notes	24,200	24,406
Fair Value, Measurements, Nonrecurring \| Estimated Fair Value \| Level 3 \| SBA 7(a) loans receivable, subject to credit risk
Assets:
Loans receivable	33,296	28,041
Fair Value, Measurements, Nonrecurring \| Estimated Fair Value \| Level 3 \| SBA 7(a) loans receivable, subject to loan-backed notes
Assets:
Loans receivable	26,001	30,076
Fair Value, Measurements, Nonrecurring \| Estimated Fair Value \| Level 3 \| SBA 7(a) loans receivable, paycheck protection program
Assets:
Loans receivable	16,016	0
Fair Value, Measurements, Nonrecurring \| Estimated Fair Value \| Level 3 \| SBA 7(a) loans receivable, subject to secured borrowings
Assets:
Loans receivable	9,018	12,780
Fair Value, Measurements, Nonrecurring \| Estimated Fair Value \| Level 3 \| SBA 7(a) loans receivable, held for sale
Assets:
Loans receivable	$ 9,695	$ 1,753

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611

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- Definition

Fair value of subordinated debt obligations including, but not limited to, subordinated loan, subordinated bond, subordinated debenture or junior debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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- 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

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