COMMERCIAL MORTGAGE LOANS HELD-FOR-INVESTMENT - Summary of Commercial Loan Risk Ratings (Details)	6 Months Ended	12 Months Ended
Jun. 30, 2022 USD ($) mortgage_loan	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) mortgage_loan
Financing Receivable, Credit Quality Indicator [Line Items]
Average risk rating, moderate			2.3
Purchase of commercial loans held for investment	$ 222,142,167	$ 338,386,251
Risk rating, 2
Financing Receivable, Credit Quality Indicator [Line Items]
Average risk rating, moderate	2.3
Commercial Real Estate Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans \| mortgage_loan	69		66
Unpaid Principal Balance	$ 1,033,971,397		$ 1,001,869,994
Net Carrying Value	1,033,649,358		$ 1,001,825,294
Purchase of commercial loans held for investment	$ 222,142,167
Commercial Real Estate Portfolio Segment \| Risk rating, 1
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans \| mortgage_loan	0		0
Unpaid Principal Balance	$ 0		$ 0
Net Carrying Value	$ 0		$ 0
Commercial Real Estate Portfolio Segment \| Risk rating, 2
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans \| mortgage_loan	45		40
Unpaid Principal Balance	$ 667,068,717		$ 634,438,386
Net Carrying Value	667,068,717		$ 634,438,386
Commercial loans that paid off	83,000,000
Purchase of commercial loans held for investment	119,000,000
Transition of commercial loans held for sale	$ 76,700,000
Commercial Real Estate Portfolio Segment \| Risk rating, 3
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans \| mortgage_loan	23		23
Unpaid Principal Balance	$ 355,154,481		$ 342,350,405
Net Carrying Value	$ 355,184,356		$ 342,305,705
Average risk rating, percentage	98.90%		97.50%
Commercial loans that paid off	$ 99,000,000
Purchase of commercial loans held for investment	103,200,000
Transition of commercial loans held for sale	$ 80,000,000.0
Commercial Real Estate Portfolio Segment \| Risk rating, 4
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans \| mortgage_loan	0		3
Unpaid Principal Balance	$ 0		$ 25,081,203
Net Carrying Value	0		$ 25,081,203
Commercial loans that paid off	8,000,000
Transition of commercial loans held for sale	$ 5,300,000
Commercial Real Estate Portfolio Segment \| Risk rating, 5
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans \| mortgage_loan	1		0
Unpaid Principal Balance	$ 11,748,199		$ 0
Net Carrying Value	11,396,285		$ 0
Transition of commercial loans held for sale	$ 11,700,000

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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

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

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
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The cash inflow from collection of repayments from borrowers on loans that are held with the intention to resell in the near future; includes mortgages and other types of loans.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 16
-Subparagraph (a)
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-Name Accounting Standards Codification
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-Section 45
-Paragraph 21
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