SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) - USD ($)		9 Months Ended	12 Months Ended
	Feb. 14, 2019	Sep. 30, 2019	Dec. 31, 2018	Jan. 15, 2019	Dec. 15, 2015
Debt and Equity Securities, FV-NI [Line Items]
Maximum exposure to loss from consolidated trusts		$ 0	$ 4,762,149
Non-accrual status		0
Recognized impairment		0
Allowance for loan losses		0
Principal amount		40,250,000
Deferred financing costs amortized		$ 1,090,372
Common stock, shares authorized (in shares)		450,000,000	450,000,000
Common stock, par value (in dollars per share)		$ 0.01	$ 0.01
Common stock, shares issued (in shares)		23,687,664	23,687,664
Common stock, shares outstanding (in shares)		23,687,664	23,687,664
Stock repurchase program, authorized amount					$ 10,000,000
Preferred stock, shares outstanding (in shares)		0	1,610,000
Preferred stock, dividend rate, percentage		8.75%	8.75%
Preferred stock, liquidation preference (in dollars per share)		$ 25	$ 25
Preferred stock, shares authorized (in shares)		50,000,000	50,000,000
Preferred stock, par value (in dollars per share)		$ 0.01	$ 0.01
Preferred stock, shares issued (in shares)		0	1,610,000
Tax liability			$ 1,960,000
Redeemable Preferred Stock
Debt and Equity Securities, FV-NI [Line Items]
Preferred stock, shares outstanding (in shares)	1,610,000
Preferred stock, dividend rate, percentage	8.75%
Preferred stock, liquidation preference (in dollars per share)	$ 25
Credit Agreement | Delayed Draw Facility
Debt and Equity Securities, FV-NI [Line Items]
Principal amount	$ 40,250,000	$ 40,250,000		$ 40,250,000
Collateralized Loan Obligations
Debt and Equity Securities, FV-NI [Line Items]
Maximum exposure to loss from consolidated trusts		$ 124,046,671	$ 124,046,671