Governmental Issuer Loans - Summary of Partnership's Investments and Remaining Funding Commitments Related to Governmental Issuer Loans (Details)		9 Months Ended		12 Months Ended
		Sep. 30, 2021 USD ($) Unit		Dec. 31, 2020 USD ($) Unit
Governmental Issuer Loans [Line Items]
Units | Unit		4,332
Maximum Remaining Commitment		$ 152,121,106
SIFMA [Member]
Governmental Issuer Loans [Line Items]
Variable Interest Rate		2.25%		2.25%
Scharbauer Flats Apartments [Member]
Governmental Issuer Loans [Line Items]
Maturity Date	[1]	Jan. 01, 2023
Maximum Remaining Commitment		$ 20,850,387
Oasis at Twin Lakes [Member]
Governmental Issuer Loans [Line Items]
Maturity Date	[1]	Aug. 01, 2023
Maximum Remaining Commitment		$ 13,755,209
Centennial Crossings [Member]
Governmental Issuer Loans [Line Items]
Maturity Date	[1]	Sep. 01, 2023
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
Legacy Commons at Signal Hills [Member] | SOFR [Member]
Governmental Issuer Loans [Line Items]
Variable Interest Rate	[2]	3.07%
Hilltop at Signal Hills [Member]
Governmental Issuer Loans [Line Items]
Maturity Date	[1]	Aug. 01, 2023
Maximum Remaining Commitment		$ 20,197,939
Hilltop at Signal Hills [Member] | SOFR [Member]
Governmental Issuer Loans [Line Items]
Variable Interest Rate	[2]	3.07%
Osprey Village [Member]
Governmental Issuer Loans [Line Items]
Maturity Date	[1]	Aug. 01, 2024
Maximum Remaining Commitment		$ 24,500,000
Osprey Village [Member] | SOFR [Member]
Governmental Issuer Loans [Line Items]
Variable Interest Rate	[2]	3.07%
Willow Place Apartments [Member]
Governmental Issuer Loans [Line Items]
Maturity Date	[1]	Oct. 01, 2024
Maximum Remaining Commitment		$ 20,351,328
Willow Place Apartments [Member] | SOFR [Member]
Governmental Issuer Loans [Line Items]
Variable Interest Rate	[3]	3.30%
Governmental Issuer Loans [Member] | TOB Trust [Member]
Governmental Issuer Loans [Line Items]
Amortized Cost		$ 165,986,438		$ 64,863,657
Maximum Remaining Commitment		$ 120,659,185
Governmental Issuer Loans [Member] | Scharbauer Flats Apartments [Member] | TOB Trust [Member] | Midland, TX [Member]
Governmental Issuer Loans [Line Items]
Month Acquired		June 2020	[4]	June 2020	[5]
Units | Unit		300	[4]	300	[5]
Maturity Date		Jan. 01, 2023	[4],[6]	Jan. 01, 2023	[5],[7]
Current Interest Rate		3.15%	[4]	3.19%	[5]
Amortized Cost		$ 40,000,000	[4]	$ 40,000,000	[5]
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%	[4]	3.10%	[5]
Governmental Issuer Loans [Member] | Oasis at Twin Lakes [Member] | TOB Trust [Member] | Roseville, MN [Member]
Governmental Issuer Loans [Line Items]
Month Acquired		July 2020	[4]	July 2020	[5]
Units | Unit		228	[4]	228	[5]
Maturity Date		Aug. 01, 2023	[4],[6]	Aug. 01, 2023	[5],[7]
Current Interest Rate		3.75%	[4]	3.75%	[5]
Amortized Cost		$ 34,000,000	[4]	$ 14,403,000	[5]
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	[8],[9]	3.25%	[4]	3.25%	[5]
Governmental Issuer Loans [Member] | Centennial Crossings [Member] | TOB Trust [Member] | Centennial, CO [Member]
Governmental Issuer Loans [Line Items]
Month Acquired		August 2020	[4]	August 2020	[5]
Units | Unit		209	[4]	209	[5]
Maturity Date		Sep. 01, 2023	[4],[6]	Sep. 01, 2023	[5],[7]
Current Interest Rate		3.25%	[4]	3.25%	[5]
Amortized Cost		$ 31,894,945	[4]	$ 10,460,657	[5]
Maximum Remaining Commitment	[4]	$ 1,185,055
Governmental Issuer Loans [Member] | Centennial Crossings [Member] | TOB Trust [Member] | SIFMA [Member] | Centennial, CO [Member]
Governmental Issuer Loans [Line Items]
Variable Interest Rate	[8]	2.75%	[4]	2.75%	[5]
Governmental Issuer Loans [Member] | Legacy Commons at Signal Hills [Member] | TOB Trust [Member] | St. Paul, MN [Member]
Governmental Issuer Loans [Line Items]
Month Acquired	[4]	January 2021
Units | Unit	[4]	247
Maturity Date	[4],[6]	Feb. 01, 2024
Current Interest Rate	[4]	3.57%
Amortized Cost	[4]	$ 26,862,183
Maximum Remaining Commitment	[4]	$ 7,757,817
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	[4],[8]	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	[4]	January 2021
Units | Unit	[4]	146
Maturity Date	[4],[6]	Aug. 01, 2023
Current Interest Rate	[4]	3.57%
Amortized Cost	[4]	$ 14,995,969
Maximum Remaining Commitment	[4]	$ 9,454,031
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	[4],[8]	3.07%
Governmental Issuer Loans [Member] | Hope on Avalon [Member] | TOB Trust [Member]
Governmental Issuer Loans [Line Items]
Maturity Date	[10]	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	[6]	Feb. 01, 2023
Current Interest Rate		4.60%
Amortized Cost		$ 8,981,200
Maximum Remaining Commitment		$ 14,408,800
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	[8]	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	[6]	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	[8]	3.75%
Governmental Issuer Loans [Member] | Osprey Village [Member] | TOB Trust [Member] | Kissimmee FL [Member]
Governmental Issuer Loans [Line Items]
Month Acquired	[4]	July 2021
Units | Unit	[4]	383
Maturity Date	[4],[6]	Aug. 01, 2024
Current Interest Rate	[4]	3.57%
Amortized Cost	[4]	$ 3,589,110
Maximum Remaining Commitment	[4]	$ 56,410,890
Governmental Issuer Loans [Member] | Osprey Village [Member] | TOB Trust [Member] | SOFR [Member] | Kissimmee FL [Member]
Governmental Issuer Loans [Line Items]
Variable Interest Rate	[4],[8]	3.07%
Governmental Issuer Loans [Member] | Willow Place Apartments [Member] | TOB Trust [Member] | McDonough, GA [Member]
Governmental Issuer Loans [Line Items]
Month Acquired	[4]	September 2021
Units | Unit	[4]	182
Maturity Date	[4],[6]	Oct. 01, 2024
Current Interest Rate	[4]	3.55%
Amortized Cost	[4]	$ 1,971,786
Maximum Remaining Commitment	[4]	$ 23,028,214
Governmental Issuer Loans [Member] | Willow Place Apartments [Member] | TOB Trust [Member] | SOFR [Member] | McDonough, GA [Member]
Governmental Issuer Loans [Line Items]
Variable Interest Rate	[4],[8]	3.30%

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

[2] The index is subject to a floor of 0.5%

[3] The index is subject to a floor of 0.25%

[4] The Freddie Mac servicer that has forward committed to purchase the GIL at maturity is an affiliate of the Partnership (Note 22).

[5] The Freddie Mac servicer that has forward committed to purchase the GIL at maturity is an affiliate of the Partnership (Note 22).

[6] 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.

[7] 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.

[8] The variable index interest rate component is subject to a floor.

[9] The variable rate decreases to SIFMA plus 2.25% upon completion of construction.

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