SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, List of Investments (Details)	Dec. 31, 2020 USD ($)
Fair Value Option [Abstract]
Fair Value	$ 40,003,140
FSP Satellite Place [Member] | Corporation [Member] | Non-Traded Company [Member]
Fair Value Option [Abstract]
Ownership percentage	28.73%
Fair Value	$ 2,214,310
5210 Fountaingate, LP [Member] | Limited Partnership [Member] | LP Interest [Member]
Fair Value Option [Abstract]
Ownership percentage	9.92%
Fair Value	$ 494,442
Bishop Berkeley, LLC [Member] | Limited Liability Company [Member] | LP Interest [Member]
Fair Value Option [Abstract]
Ownership percentage	69.03%
Fair Value	$ 3,869,289
BP3 Affiliate, LLC [Member] | Limited Liability Company [Member] | LP Interest [Member]
Fair Value Option [Abstract]
Ownership percentage	12.51%
Fair Value	$ 1,668,000
BR Galleria Village Investment Co, LLC [Member] | Limited Liability Company [Member] | LP Interest [Member]
Fair Value Option [Abstract]
Ownership percentage	13.82%
Fair Value	$ 2,463,774
Britannia Preferred Members, LLC -Class 1 [Member] | Limited Liability Company [Member] | LP Interest [Member]
Fair Value Option [Abstract]
Ownership percentage	16.85%
Fair Value	$ 3,765,650
Britannia Preferred Members, LLC - Class 2 [Member] | Limited Liability Company [Member] | LP Interest [Member]
Fair Value Option [Abstract]
Ownership percentage	33.41%
Fair Value	$ 6,528,403
Capitol Hill Partners, LLC [Member] | Limited Liability Company [Member] | LP Interest [Member]
Fair Value Option [Abstract]
Ownership percentage	25.93%
Fair Value	$ 1,394,600
Citrus Park Hotel Holdings, LLC [Member] | Limited Liability Company [Member] | LP Interest [Member]
Fair Value Option [Abstract]
Ownership percentage	35.27%
Fair Value	$ 5,000,000
Dimensions 28, LLP [Member] | Limited Liability Partnership [Member] | LP Interest [Member]
Fair Value Option [Abstract]
Ownership percentage	90.00%
Fair Value	$ 11,481,048
Lakemont Partners, LLC [Member] | Limited Liability Company [Member] | LP Interest [Member]
Fair Value Option [Abstract]
Ownership percentage	17.02%
Fair Value	$ 861,710
Secured Income L.P. [Member] | Limited Partnership [Member] | LP Interest [Member]
Fair Value Option [Abstract]
Ownership percentage	6.57%
Fair Value	$ 261,914