Segments - Summary of Partnership Reportable Segment Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Total revenues
Total revenues	$ 16,458,034	$ 16,040,388
Interest expense
Interest expense	4,882,305	5,442,253
Depreciation expense
Depreciation expense	903,953	1,355,231
Partnership net income (loss)
Partnership net income (loss)	6,004,304	7,288,862
Total assets
Total assets	1,033,499,630		$ 1,069,767,999
Operating Segments [Member] | Mortgage Revenue Bond Investments Segment [Member]
Total revenues
Total revenues	12,070,556	10,588,498
Interest expense
Interest expense	4,517,620	4,571,455
Partnership net income (loss)
Partnership net income (loss)	4,299,595	2,229,053
Total assets
Total assets	902,402,580		937,565,390
Operating Segments [Member] | MF Properties [Member]
Total revenues
Total revenues	2,336,512	3,792,415
Interest expense
Interest expense	390,701	525,587
Depreciation expense
Depreciation expense	903,953	1,355,231
Partnership net income (loss)
Partnership net income (loss)	(362,730)	3,745,545
Total assets
Total assets	83,048,522		83,514,758
Operating Segments [Member] | Public Housing Capital Fund Trusts [Member]
Total revenues
Total revenues	620,106	708,786
Interest expense
Interest expense	(26,016)	345,211
Partnership net income (loss)
Partnership net income (loss)	646,122	363,575
Total assets
Total assets	49,302,896		49,918,434
Operating Segments [Member] | Other Investments [Member]
Total revenues
Total revenues	1,430,860	950,689
Partnership net income (loss)
Partnership net income (loss)	1,421,317	$ 950,689
Total assets
Total assets	68,615,475		55,573,834
Consolidation, Eliminations [Member]
Total assets
Total assets	$ (69,869,843)		$ (56,804,417)