Fair Value of Financial Instruments - Summary of Range of Effective Yields and Weighted Average Effective Yields of Partnership's Investments (Details)		Dec. 31, 2020	Dec. 31, 2019
Taxable Mortgage Revenue Bonds [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Weighted Average Effective Yields	[1]	7.30%	8.80%
Taxable Mortgage Revenue Bonds [Member] | Effective rate - minimum [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Range of Effective Yields		7.10%	8.70%
Taxable Mortgage Revenue Bonds [Member] | Effective rate - maximum [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Range of Effective Yields		7.40%	8.90%
Bond Purchase Commitment [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Range of Effective Yields		3.50%
Weighted Average Effective Yields	[1]	3.50%
Mortgage Revenue Bonds [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Weighted Average Effective Yields	[1]	3.00%	3.80%
Mortgage Revenue Bonds [Member] | Effective rate - minimum [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Range of Effective Yields		1.40%	2.40%
Mortgage Revenue Bonds [Member] | Effective rate - maximum [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Range of Effective Yields		13.30%	8.50%

[1] ^{Weighted by the total principal outstanding of all the respective securities as of the reporting date.}