COMMERCIAL MORTGAGE LOANS HELD-FOR-INVESTMENT - Summary of Commercial Loan Risk Ratings (Details)		9 Months Ended		12 Months Ended
		Sep. 30, 2022 USD ($) mortgage_loan	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) mortgage_loan
Financing Receivable, Credit Quality Indicator [Line Items]
Outstanding Principal	[1]	$ 1,045,953,691		$ 1,001,825,294
Average risk rating, moderate		2.7		2.3
Purchase of commercial loans held for investment		$ 269,596,827	$ 647,459,391
Commercial Real Estate Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | mortgage_loan		70		66
Outstanding Principal		$ 1,045,929,099		$ 1,001,869,994
Year 1		132,563,390		797,454,369
Year 2		820,262,406		19,827,960
Year 3				109,327,972
Year 4		42,077,193		55,526,061
Year 5		29,504,354		$ 19,688,932
Before year 5		19,673,411
Purchase of commercial loans held for investment		$ 269,596,827
Commercial Real Estate Portfolio Segment | Risk rating, 1
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | mortgage_loan		0		0
Outstanding Principal		$ 0		$ 0
Year 1		0		0
Year 2		0		0
Year 3				0
Year 4		0		0
Year 5		0		$ 0
Before year 5		$ 0
Commercial Real Estate Portfolio Segment | Risk rating, 2
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | mortgage_loan		23		40
Outstanding Principal		$ 302,083,221		$ 634,438,386
Year 1		24,084,750		596,052,235
Year 2		273,552,471		4,920,000
Year 3				33,466,151
Year 4		0		0
Year 5		4,446,000		$ 0
Before year 5		0
Commercial loans that paid off		110,000,000
Purchase of commercial loans held for investment		69,000,000
Transition of commercial loans held for sale to a lower risk rating		$ 86,200,000
Commercial Real Estate Portfolio Segment | Risk rating, 3
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | mortgage_loan		45		23
Outstanding Principal		$ 720,837,210		$ 342,350,405
Year 1		108,478,640		201,402,134
Year 2		533,959,935		6,870,561
Year 3				70,566,216
Year 4		42,077,193		43,777,862
Year 5		16,672,623		$ 19,688,932
Before year 5		$ 19,673,411
Average risk rating, percentage		97.80%		97.50%
Commercial loans that paid off		$ 99,000,000
Purchase of commercial loans held for investment		193,600,000
Transition of commercial loans held for sale to a higher risk rating		377,600,000
Transition of commercial loans held for sale to a lower risk rating		$ 5,300,000
Commercial Real Estate Portfolio Segment | Risk rating, 4
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | mortgage_loan		1		3
Outstanding Principal		$ 12,750,000		$ 25,081,203
Year 1		0		0
Year 2		12,750,000		8,037,399
Year 3				5,295,605
Year 4		0		11,748,199
Year 5		0		$ 0
Before year 5		0
Commercial loans that paid off		9,500,000
Transition of commercial loans held for sale to a higher risk rating		$ 12,800,000
Commercial Real Estate Portfolio Segment | Risk rating, 5
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | mortgage_loan		1		0
Outstanding Principal		$ 10,258,668		$ 0
Year 1		0		0
Year 2		0		0
Year 3				0
Year 4		0		0
Year 5		8,385,731		$ 0
Before year 5		0
Transition of commercial loans held for sale to a higher risk rating		$ 10,300,000

[1] Our consolidated balance sheets include assets and liabilities of consolidated variable interest entities ("VIEs") as the Company was the primary beneficiary of these VIEs. As of September 30, 2022 and December 31, 2021, assets of consolidated VIEs totaled $1,004,040,687 and $1,003,896,995, respectively and the liabilities of consolidated VIEs totaled $830,248,911 and $827,390,435 respectively. See Note 4 for further discussion.