Governmental Issuer Loans - Summary of Partnership's Investments and Remaining Funding Commitments Related to Governmental Issuer Loans (Details)		3 Months Ended		12 Months Ended
		Mar. 31, 2021 USD ($) Unit		Dec. 31, 2020 USD ($) Unit
Governmental Issuer Loans [Line Items]
Units | Unit		3,468
Maximum Remaining Commitment		$ 121,218,749
SIFMA [Member]
Governmental Issuer Loans [Line Items]
Variable Interest Rate		2.25%		2.25%
Scharbauer Flats Apartments [Member]
Governmental Issuer Loans [Line Items]
Maximum Remaining Commitment		$ 21,850,387
Oasis at Twin Lakes [Member]
Governmental Issuer Loans [Line Items]
Maximum Remaining Commitment		26,704,180
Centennial Crossings [Member]
Governmental Issuer Loans [Line Items]
Maximum Remaining Commitment		$ 21,232,271
Legacy Commons at Signal Hills [Member]
Governmental Issuer Loans [Line Items]
Maturity Date	[1]	Feb. 01, 2024
Maximum Remaining Commitment		$ 31,233,972
Hilltop at Signal Hills [Member]
Governmental Issuer Loans [Line Items]
Maturity Date	[1]	Aug. 01, 2023
Maximum Remaining Commitment		$ 20,197,939
Governmental Issuer Loans [Member] | TOB Trust [Member]
Governmental Issuer Loans [Line Items]
Amortized Cost		103,931,256		$ 64,863,657
Maximum Remaining Commitment		$ 97,714,367
Governmental Issuer Loans [Member] | Scharbauer Flats Apartments [Member] | TOB Trust [Member] | Midland, TX [Member]
Governmental Issuer Loans [Line Items]
Month Acquired		June 2020	[2]	June 2020	[3]
Units | Unit		300	[2]	300	[3]
Maturity Date		Jan. 01, 2023	[2],[4]	Jan. 01, 2023	[3],[5]
Current Interest Rate		3.15%	[2]	3.19%	[3]
Amortized Cost		$ 40,000,000	[2]	$ 40,000,000	[3]
Governmental Issuer Loans [Member] | Scharbauer Flats Apartments [Member] | TOB Trust [Member] | SIFMA [Member] | Midland, TX [Member]
Governmental Issuer Loans [Line Items]
Variable Interest Rate		3.10%	[2]	3.10%	[3]
Governmental Issuer Loans [Member] | Oasis at Twin Lakes [Member] | TOB Trust [Member] | Roseville, MN [Member]
Governmental Issuer Loans [Line Items]
Month Acquired		July 2020	[2]	July 2020	[3]
Units | Unit		228	[2]	228	[3]
Maturity Date		Aug. 01, 2023	[2],[4]	Aug. 01, 2023	[3],[5]
Current Interest Rate		3.75%	[2]	3.75%	[3]
Amortized Cost		$ 24,733,130	[2]	$ 14,403,000	[3]
Maximum Remaining Commitment	[2]	$ 9,266,870
Governmental Issuer Loans [Member] | Oasis at Twin Lakes [Member] | TOB Trust [Member] | SIFMA [Member] | Roseville, MN [Member]
Governmental Issuer Loans [Line Items]
Variable Interest Rate	[6],[7]	3.25%	[2]	3.25%	[3]
Governmental Issuer Loans [Member] | Centennial Crossings [Member] | TOB Trust [Member] | Centennial, CO [Member]
Governmental Issuer Loans [Line Items]
Month Acquired		August 2020	[2]	August 2020	[3]
Units | Unit		209	[2]	209	[3]
Maturity Date		Sep. 01, 2023	[2],[4]	Sep. 01, 2023	[3],[5]
Current Interest Rate		3.25%	[2]	3.25%	[3]
Amortized Cost		$ 15,182,744	[2]	$ 10,460,657	[3]
Maximum Remaining Commitment	[2]	$ 17,897,256
Governmental Issuer Loans [Member] | Centennial Crossings [Member] | TOB Trust [Member] | SIFMA [Member] | Centennial, CO [Member]
Governmental Issuer Loans [Line Items]
Variable Interest Rate	[6]	2.75%	[2]	2.75%	[3]
Governmental Issuer Loans [Member] | Legacy Commons at Signal Hills [Member] | TOB Trust [Member] | St. Paul, MN [Member]
Governmental Issuer Loans [Line Items]
Month Acquired	[2]	January 2021
Units | Unit	[2]	247
Maturity Date	[2],[4]	Feb. 01, 2024
Current Interest Rate	[2]	3.57%
Amortized Cost	[2]	$ 9,917,887
Maximum Remaining Commitment	[2]	$ 24,702,113
Governmental Issuer Loans [Member] | Legacy Commons at Signal Hills [Member] | TOB Trust [Member] | SOFR [Member] | St. Paul, MN [Member]
Governmental Issuer Loans [Line Items]
Variable Interest Rate	[2],[6]	3.07%
Governmental Issuer Loans [Member] | Hilltop at Signal Hills [Member] | TOB Trust [Member] | St. Paul, MN [Member]
Governmental Issuer Loans [Line Items]
Month Acquired	[2]	January 2021
Units | Unit	[2]	146
Maturity Date	[2],[4]	Aug. 01, 2023
Current Interest Rate	[2]	3.57%
Amortized Cost	[2]	$ 4,075,050
Maximum Remaining Commitment	[2]	$ 20,374,950
Governmental Issuer Loans [Member] | Hilltop at Signal Hills [Member] | TOB Trust [Member] | SOFR [Member] | St. Paul, MN [Member]
Governmental Issuer Loans [Line Items]
Variable Interest Rate	[2],[6]	3.07%
Governmental Issuer Loans [Member] | Hope on Avalon [Member] | TOB Trust [Member]
Governmental Issuer Loans [Line Items]
Maturity Date	[8]	Feb. 01, 2023
Governmental Issuer Loans [Member] | Hope on Avalon [Member] | TOB Trust [Member] | Los Angeles, CA [Member]
Governmental Issuer Loans [Line Items]
Month Acquired		January 2021
Units | Unit		88
Maturity Date	[4]	Feb. 01, 2023
Current Interest Rate		4.60%
Amortized Cost		$ 6,331,200
Maximum Remaining Commitment		$ 17,058,800
Governmental Issuer Loans [Member] | Hope on Avalon [Member] | TOB Trust [Member] | SIFMA [Member] | Los Angeles, CA [Member]
Governmental Issuer Loans [Line Items]
Variable Interest Rate	[6]	3.75%
Governmental Issuer Loans [Member] | Hope on Broadway [Member] | TOB Trust [Member] | Los Angeles, CA [Member]
Governmental Issuer Loans [Line Items]
Month Acquired		January 2021
Units | Unit		49
Maturity Date	[4]	Feb. 01, 2023
Current Interest Rate		4.60%
Amortized Cost		$ 3,691,245
Maximum Remaining Commitment		$ 8,414,378
Governmental Issuer Loans [Member] | Hope on Broadway [Member] | TOB Trust [Member] | SIFMA [Member] | Los Angeles, CA [Member]
Governmental Issuer Loans [Line Items]
Variable Interest Rate	[6]	3.75%

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

[2] ^{An affiliate of the Partnership has forward committed to purchase the GIL at maturity if the property has reached stabilization and other conditions are met (Note 21).}

[3] ^{An affiliate of the Partnership has forward committed to purchase the GILs at maturity if the property has reached stabilization and other conditions are met (Note 21).}

[4] ^{The borrower may elect to extend the maturity date to for a period ranging between six and twelve months upon meeting certain conditions, including payment of a non-refundable extension fee.}

[5] The borrower may elect to extend the maturity date to for a period ranging between six and twelve months upon payment of a non-refundable extension fee.

[6] ^{The variable index interest rate component is subject to a floor.}

[7] ^{The variable rate decreases to SIFMA plus 2.25% upon completion of construction.}

[8] The borrower has the option to extend the maturity up to six months upon payment of a non-refundable extension fee.