FAIR VALUE - Fair Value Information on Financial Instruments (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 10,300,620	$ 7,882,862
Restricted cash	81,037,212	51,330,950
Total assets	657,351,216	679,352,035
Collateralized loan obligations	505,438,271	503,978,918
Secured Term Loan	39,275,571	0
Total liabilities	548,129,763	529,148,697
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	10,300,620	7,882,862
Restricted cash	81,037,212	51,330,950
Cash held in securitization trusts, at fair value		24,357,335
Commercial mortgage loans held-for-investment	559,521,552	555,172,891
Total assets	650,859,384	638,744,038
Collateralized loan obligations	505,438,271	503,978,918
Secured Term Loan	39,275,571
Total liabilities	544,713,842	503,978,918
Face Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	10,300,620	7,882,862
Restricted cash	81,037,212	51,330,950
Cash held in securitization trusts, at fair value		24,357,335
Commercial mortgage loans held-for-investment	559,521,552	555,172,891
Total assets	650,859,384	638,744,038
Collateralized loan obligations	510,181,000	510,181,000
Secured Term Loan	40,250,000
Total liabilities	550,431,000	510,181,000
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	10,300,620	7,882,862
Restricted cash	81,037,212	51,330,950
Cash held in securitization trusts, at fair value		24,357,335
Commercial mortgage loans held-for-investment	559,521,552	555,172,891
Total assets	650,859,384	638,744,038
Collateralized loan obligations	510,210,986	509,000,439
Secured Term Loan	41,794,352
Total liabilities	$ 552,005,338	$ 509,000,439