Segments - Summary of Partnership Reportable Segment Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Total revenues
Total revenues	$ 26,001,115	$ 16,234,830	$ 58,244,314	$ 48,509,518
Interest expense
Interest expense	5,985,263	5,714,181	16,786,435	16,997,761
Depreciation expense
Depreciation expense	849,516	1,256,202	2,672,925	3,876,768
Partnership net income (loss)
Partnership net income (loss)	17,883,055	3,545,483	27,225,480	14,943,745
Total assets
Total assets	1,001,216,917		1,001,216,917		$ 1,069,767,999
Operating Segments [Member] | Mortgage Revenue Bond Investments Segment [Member]
Total revenues
Total revenues	21,440,970	11,035,530	44,609,666	32,683,968
Interest expense
Interest expense	5,225,938	4,786,151	15,008,698	14,295,635
Partnership net income (loss)
Partnership net income (loss)	12,039,700	2,604,989	18,647,585	7,426,810
Total assets
Total assets	882,106,195		882,106,195		937,565,390
Operating Segments [Member] | MF Properties [Member]
Total revenues
Total revenues	2,285,736	3,257,174	7,099,690	10,356,311
Interest expense
Interest expense	420,950	556,200	1,219,782	1,616,032
Depreciation expense
Depreciation expense	849,516	1,256,202	2,672,925	3,876,768
Partnership net income (loss)
Partnership net income (loss)	4,228,494	(626,827)	3,770,339	3,136,765
Total assets
Total assets	71,664,933		71,664,933		83,514,758
Operating Segments [Member] | Public Housing Capital Fund Trusts [Member]
Total revenues
Total revenues	617,661	711,823	1,860,728	2,139,791
Interest expense
Interest expense	338,375	371,830	557,955	1,086,094
Partnership net income (loss)
Partnership net income (loss)	(30,672)	339,993	161,753	1,053,697
Total assets
Total assets	49,099,991		49,099,991		49,918,434
Operating Segments [Member] | Other Investments [Member]
Total revenues
Total revenues	1,656,748	1,230,303	4,674,230	3,329,448
Partnership net income (loss)
Partnership net income (loss)	1,645,533	$ 1,227,328	4,645,803	$ 3,326,473
Total assets
Total assets	95,948,632		95,948,632		55,573,834
Consolidation, Eliminations [Member]
Total assets
Total assets	$ (97,602,834)		$ (97,602,834)		$ (56,804,417)