COMMERCIAL MORTGAGE LOANS HELD-FOR-INVESTMENT - Summary of Commercial Loan Risk Ratings (Details)		3 Months Ended		12 Months Ended
		Mar. 31, 2023 USD ($) mortgageLoan	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($) mortgageLoan
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial mortgage loans held-for-investment, at amortized cost	[1]	$ 1,019,821,199		$ 1,076,148,186
Average risk rating, moderate		3.2		3.0
Purchase of commercial loans held for investment		$ 0	$ 184,992,167
Commercial Real Estate Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | mortgageLoan		67		71
Commercial mortgage loans held-for-investment, at amortized cost		$ 1,020,479,107		$ 1,076,865,099
Year 1		200,895,674		201,852,224
Year 2		737,717,487		785,619,407
Year 4		41,532,605		42,077,193
Year 5		16,669,520		22,672,623
Before year 5		$ 19,648,386		$ 19,688,071
Commercial Real Estate Portfolio Segment | Risk rating, 1
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | mortgageLoan		0		0
Commercial mortgage loans held-for-investment, at amortized cost		$ 0		$ 0
Year 1		0		0
Year 2		0		0
Year 4		0		0
Year 5		0		0
Before year 5		$ 0		$ 0
Commercial Real Estate Portfolio Segment | Risk rating, 2
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | mortgageLoan		5		11
Commercial mortgage loans held-for-investment, at amortized cost		$ 76,325,000		$ 153,933,750
Year 1		75,233,321		85,198,084
Year 2		0		67,999,500
Year 4		0		0
Year 5		0		0
Before year 5		0		$ 0
Commercial loans that paid off		$ 46,100,000
Commercial Real Estate Portfolio Segment | Risk rating, 3
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | mortgageLoan		49		55
Commercial mortgage loans held-for-investment, at amortized cost		$ 774,200,050		$ 852,474,681
Year 1		59,470,781		101,654,140
Year 2		671,105,519		672,421,907
Year 4		4,804,061		42,077,193
Year 5		16,669,520		16,672,623
Before year 5		$ 19,648,386		$ 19,688,071
Average risk rating, percentage		83.30%		93.80%
Transition of commercial loans held for sale to a higher risk rating		$ 77,600,000
Transition of commercial loans held for sale to a lower risk rating		$ 23,300,000
Commercial Real Estate Portfolio Segment | Risk rating, 4
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | mortgageLoan		12		3
Commercial mortgage loans held-for-investment, at amortized cost		$ 157,279,802		$ 47,448,000
Year 1		66,191,572		15,000,000
Year 2		53,937,713		32,448,000
Year 4		36,728,544		0
Year 5		0		0
Before year 5		0		$ 0
Transition of commercial loans held for sale to a higher risk rating		$ 133,200,000
Commercial Real Estate Portfolio Segment | Risk rating, 5
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | mortgageLoan		1		2
Commercial mortgage loans held-for-investment, at amortized cost		$ 12,674,255		$ 23,008,668
Year 1		0		0
Year 2		12,674,255		12,750,000
Year 4		0		0
Year 5		0		6,000,000
Before year 5		0		$ 0
Commercial loans that paid off		$ 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 March 31, 2023 and December 31, 2022, assets of consolidated VIEs totaled $1,002,563,861 and $1,005,507,371, respectively and the liabilities of consolidated VIEs totaled $832,342,571 and $831,575,144 respectively. See Note 4 for further discussion.