Loans Payable - Interest accrued and accumulated amortization of capitalized issuance costs (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Accrued interest	$ 214,042	$ 219,476
Accumulated amortization of capitalized issuance costs	801,565	637,688
Amortization and preferred stock dividends on mandatorily redeemable preferred stock
Debt Instrument [Line Items]
Accrued interest	70,004	70,004
Accumulated amortization of capitalized issuance costs	589,639	366,758
Franklin Square Property
Debt Instrument [Line Items]
Accrued interest	43,448
Accumulated amortization of capitalized issuance costs	30,736	2,364
Hanover Square Property
Debt Instrument [Line Items]
Accrued interest	38,792	38,287
Accumulated amortization of capitalized issuance costs	59,880	46,990
Ashley Plaza Property
Debt Instrument [Line Items]
Accrued interest	35,296
Accumulated amortization of capitalized issuance costs	58,109	40,679
Clemson Best Western Property
Debt Instrument [Line Items]
Accrued interest		47,716
Accumulated amortization of capitalized issuance costs		134,622
Brookfield Center Property.
Debt Instrument [Line Items]
Accrued interest		15,979
Accumulated amortization of capitalized issuance costs	36,893	25,542
Lancer Center Property
Debt Instrument [Line Items]
Accrued interest		22,042
Accumulated amortization of capitalized issuance costs		17,971
Greenbrier Business Center Property
Debt Instrument [Line Items]
Accrued interest		15,482
Accumulated amortization of capitalized issuance costs		924
Parkway Center
Debt Instrument [Line Items]
Accrued interest	26,502	9,966
Accumulated amortization of capitalized issuance costs	12,864	$ 1,838
Wells Fargo Facility
Debt Instrument [Line Items]
Accumulated amortization of capitalized issuance costs	$ 13,444