RELATED PARTY TRANSACTIONS, Controlled or Affiliated Investments (Predecessor Basis) (Details) - USD ($)	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2021
MPF Pacific Gateway [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Ownership interest		15.82%
Affiliated Investments [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	$ 15,916,187
Gross additions	10,955,759
Transfers	0
Gross reductions	(13,812,455)
Net realized gains (losses)	583,331
Net change in unrealized gains/(losses)	(1,534,938)
Fair value at ending balance	12,107,884
Interest/dividend/other income	1,011,245
Affiliated Investments [Member] | 5210 Fountaingate, LP [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	552,693
Gross additions	0
Transfers	0
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	(126,897)
Fair value at ending balance	425,796
Interest/dividend/other income	0
Affiliated Investments [Member] | Arrowpoint Burlington LLC [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	1,088,910
Gross additions	0
Transfers	0
Gross reductions	(1,333,331)
Net realized gains (losses)	583,331
Net change in unrealized gains/(losses)	(338,910)
Fair value at ending balance	0
Interest/dividend/other income	0
Affiliated Investments [Member] | BP3 Affiliate, LLC [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	1,350,000
Gross additions	318,000
Transfers	0
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	0
Fair value at ending balance	1,668,000
Interest/dividend/other income	0
Affiliated Investments [Member] | BR Desota Investment Co, LLC [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	4,250,000
Gross additions	0
Transfers	0
Gross reductions	(4,250,000)
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	0
Fair value at ending balance	0
Interest/dividend/other income	46,623
Affiliated Investments [Member] | BR Everwood Investment Co, LLC [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	0
Gross additions	3,750,000
Transfers	0
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	0
Fair value at ending balance	3,750,000
Interest/dividend/other income	479,871
Affiliated Investments [Member] | BR Quinn35 Investment Co, LLC [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	4,000,000
Gross additions	0
Transfers	0
Gross reductions	(4,000,000)
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	0
Fair value at ending balance	0
Interest/dividend/other income	167,768
Affiliated Investments [Member] | BR Sunrise Parc Investment Co, LLC [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	0
Gross additions	2,720,911
Transfers	0
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	0
Fair value at ending balance	2,720,911
Interest/dividend/other income	253,410
Affiliated Investments [Member] | BR Westerly Investment Co, LLC [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	0
Gross additions	4,120,667
Transfers	0
Gross reductions	(4,120,667)
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	0
Fair value at ending balance	0
Interest/dividend/other income	0
Affiliated Investments [Member] | FSP Energy Tower I Corp. Liquidating Trust [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	57,566
Gross additions	0
Transfers	0
Gross reductions	(49,637)
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	1,881
Fair value at ending balance	9,810
Interest/dividend/other income	37,438
Affiliated Investments [Member] | FSP Satellite Place [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	712,585
Gross additions	41,693
Transfers	0
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	(221,699)
Fair value at ending balance	532,579
Interest/dividend/other income	0
Affiliated Investments [Member] | Lakemont Partners, LLC [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	1,007,700
Gross additions	0
Transfers	0
Gross reductions	(58,820)
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	(91,720)
Fair value at ending balance	857,160
Interest/dividend/other income	26,135
Affiliated Investments [Member] | MPF Pacific Gateway [Member] | Class B [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	7,316
Gross additions	0
Transfers	0
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	(152)
Fair value at ending balance	7,164
Interest/dividend/other income	0
Affiliated Investments [Member] | Secured Income L.P. [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	302,009
Gross additions	0
Transfers	0
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	(40,095)
Fair value at ending balance	261,914
Interest/dividend/other income	0
Affiliated Investments [Member] | Summit Healthcare REIT, Inc. [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	2,587,408
Gross additions	4,488
Transfers	0
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	(717,346)
Fair value at ending balance	1,874,550
Interest/dividend/other income	0
Controlled Investments [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	38,488,962
Gross additions	12,829,579
Transfers	0
Gross reductions	(5,000,000)
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	(2,803,250)
Fair value at ending balance	43,515,291
Interest/dividend/other income	2,352,153
Controlled Investments [Member] | Addison NC, LLC [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	3,600,000
Gross additions	0
Transfers	(2,000,000)
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	(1,600,000)
Fair value at ending balance	0
Interest/dividend/other income	0
Controlled Investments [Member] | Addison Property Member, LLC [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	7,314,855
Gross additions	0
Transfers	(7,316,326)
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	1,471
Fair value at ending balance	0
Interest/dividend/other income	1,176,187
Controlled Investments [Member] | Bishop Berkeley, LLC [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	4,051,013
Gross additions	0
Transfers	0
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	(196,790)
Fair value at ending balance	3,854,223
Interest/dividend/other income	69,034
Controlled Investments [Member] | Britannia Preferred Members, LLC [Member] | Class 1 [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	2,986,550
Gross additions	0
Transfers	0
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	519,400
Fair value at ending balance	3,505,950
Interest/dividend/other income	0
Controlled Investments [Member] | Britannia Preferred Members, LLC [Member] | Class 2 [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	7,758,915
Gross additions	0
Transfers	0
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	(669,316)
Fair value at ending balance	7,089,599
Interest/dividend/other income	0
Controlled Investments [Member] | Capitol Hill Partners, LLC [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	1,852,500
Gross additions	0
Transfers	0
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	(383,800)
Fair value at ending balance	1,468,700
Interest/dividend/other income	0
Controlled Investments [Member] | Citrus Park Hotel Holdings, LLC [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	0
Gross additions	5,000,000
Transfers	0
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	0
Fair value at ending balance	5,000,000
Interest/dividend/other income	287,500
Controlled Investments [Member] | Coastal Realty Business Trust, REEP, Inc. [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	39,053
Gross additions	0
Transfers	0
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	(5,063)
Fair value at ending balance	33,990
Interest/dividend/other income	0
Controlled Investments [Member] | Dimensions 28, LLP [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	10,886,076
Gross additions	0
Transfers	0
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	63,612
Fair value at ending balance	10,949,688
Interest/dividend/other income	485,321
Controlled Investments [Member] | MacKenzie Realty Operating Partnership, LP [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	0
Gross additions	2,829,579
Transfers	9,316,326
Gross reductions	0
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	(532,764)
Fair value at ending balance	11,613,141
Interest/dividend/other income	0
Controlled Investments [Member] | Sunlit Holdings, LLC [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair value at beginning balance	0
Gross additions	5,000,000
Transfers	0
Gross reductions	(5,000,000)
Net realized gains (losses)	0
Net change in unrealized gains/(losses)	0
Fair value at ending balance	0
Interest/dividend/other income	$ 334,111