Property Loans, Net of Loan Loss Allowances - Summary of Outstanding Property Loans and Remaining Commitments (Details)	3 Months Ended
	Mar. 31, 2021 USD ($)
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	$ 2,000,000
Maximum Remaining Commitment	$ 121,218,749
Legacy Commons at Signal Hills [Member]
Accounts Notes And Loans Receivable [Line Items]
Date Committed	2021-01
Original Maturity Date	Feb. 01, 2024	[1]
Outstanding Balance	$ 1,000,000
Maximum Remaining Commitment	$ 31,233,972
Hilltop at Signal Hills [Member]
Accounts Notes And Loans Receivable [Line Items]
Date Committed	2021-01
Original Maturity Date	Aug. 01, 2023	[1]
Outstanding Balance	$ 1,000,000
Maximum Remaining Commitment	20,197,939
Centennial Crossings [Member]
Accounts Notes And Loans Receivable [Line Items]
Maximum Remaining Commitment	21,232,271
Oasis at Twin Lakes [Member]
Accounts Notes And Loans Receivable [Line Items]
Maximum Remaining Commitment	26,704,180
Scharbauer Flats Apartments [Member]
Accounts Notes And Loans Receivable [Line Items]
Maximum Remaining Commitment	$ 21,850,387

[1] ^{The borrower has the option to extend the maturity date up to six months.}