INVESTMENT SECURITIES - Tabular Disclosure (Details) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Debt Securities, Trading, and Equity Securities, FV-NI [Abstract]
Cost	$ 38,753,230	$ 38,753,230
Equity Securities, FV-NI, Accumulated Gross Unrealized Gain, before Tax		61,195
Equity Securities, FV-NI, Accumulated Gross Unrealized Loss, before Tax	(7,036,766)
Investment in Alpine Income Property Trust, Inc.	31,716,464	38,814,425
Common Stock
Debt Securities, Trading, and Equity Securities, FV-NI [Abstract]
Cost	15,500,000	15,500,000
Equity Securities, FV-NI, Accumulated Gross Unrealized Gain, before Tax		24,484
Equity Securities, FV-NI, Accumulated Gross Unrealized Loss, before Tax	(2,814,466)
Investment in Alpine Income Property Trust, Inc.	12,685,534	15,524,484
Operating Units
Debt Securities, Trading, and Equity Securities, FV-NI [Abstract]
Cost	23,253,230	23,253,230
Equity Securities, FV-NI, Accumulated Gross Unrealized Gain, before Tax		36,711
Equity Securities, FV-NI, Accumulated Gross Unrealized Loss, before Tax	(4,222,300)
Investment in Alpine Income Property Trust, Inc.	$ 19,030,930	$ 23,289,941