Governmental Issuer Loans - Summary of Partnership's Investments and Remaining Funding Commitments Related to Governmental Issuer Loans (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) Unit
Governmental Issuer Loans [Line Items]
Units | Unit	3,756
Maximum Remaining Commitment	$ 70,786,838
SIFMA [Member]
Governmental Issuer Loans [Line Items]
Variable interest rate	2.25%
Scharbauer Flats Apartments [Member]
Governmental Issuer Loans [Line Items]
Maturity Date	Jan. 01, 2023	[1]
Maximum Remaining Commitment	$ 21,850,387
Oasis at Twin Lakes [Member]
Governmental Issuer Loans [Line Items]
Maturity Date	Aug. 01, 2023	[2]
Maximum Remaining Commitment	$ 27,704,180
Centennial Crossings [Member]
Governmental Issuer Loans [Line Items]
Maturity Date	Sep. 01, 2023	[2]
Maximum Remaining Commitment	$ 21,232,271
Governmental Issuer Loans [Member] | TOB Trust [Member]
Governmental Issuer Loans [Line Items]
Amortized Cost	64,863,657
Maximum Remaining Commitment	$ 42,216,343
Governmental Issuer Loans [Member] | Scharbauer Flats Apartments [Member] | TOB Trust [Member] | Midland, TX [Member]
Governmental Issuer Loans [Line Items]
Date Acquired	June 2020
Units | Unit	300
Maturity Date	Jan. 01, 2023	[3]
Current Interest Rate	3.19%
Amortized Cost	$ 40,000,000
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%
Governmental Issuer Loans [Member] | Oasis at Twin Lakes [Member] | TOB Trust [Member] | Roseville, MN [Member]
Governmental Issuer Loans [Line Items]
Date Acquired	July 2020
Units | Unit	228
Maturity Date	Aug. 01, 2023	[4]
Current Interest Rate	3.75%
Amortized Cost	$ 14,403,000
Maximum Remaining Commitment	$ 19,597,000
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	3.25%	[5],[6]
Governmental Issuer Loans [Member] | Centennial Crossings [Member] | TOB Trust [Member] | Centennial, CO [Member]
Governmental Issuer Loans [Line Items]
Date Acquired	August 2020
Units | Unit	209
Maturity Date	Sep. 01, 2023	[4]
Current Interest Rate	3.25%
Amortized Cost	$ 10,460,657
Maximum Remaining Commitment	$ 22,619,343
Governmental Issuer Loans [Member] | Centennial Crossings [Member] | TOB Trust [Member] | SIFMA [Member] | Centennial, CO [Member]
Governmental Issuer Loans [Line Items]
Variable interest rate	2.75%	[6]

[1] ^{The borrower has the option to extend the maturity date with two six-month extensions.}

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

[3] ^{The borrower may automatically extend the maturity to July 2023 and may further extend the maturity to January 2024 upon payment of a non-refundable extension fee.}

[4] ^{The borrower may extend the maturity date to for a period not to exceed six months upon payment of a non-refundable extension fee.}

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

[6] ^{The SIFMA index interest rate component is subject to a floor of 0.50%.}