Segments - Summary of Partnership Reportable Segment Information (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Total revenues
Total revenues									$ 70,381,545	$ 58,978,750	$ 59,953,291
Interest expense
Interest expense									22,155,443	15,469,639	14,826,217
Depreciation expense
Depreciation expense									4,949,935	5,980,483	5,888,973
Income from continuing operations
Income from continuing operations	$ 15,647,453	$ 3,545,483	$ 4,109,400	$ 7,360,515	$ 5,623,293	$ 4,622,874	$ 11,005,829	$ 2,531,688	30,662,851	23,783,684	22,884,825
Partnership Net income
Partnership Net income									30,591,198	23,784,507	26,609,023
Total assets
Total assets	1,069,767,999				944,113,674				1,069,767,999	944,113,674
Operating Segments [Member] | Mortgage Revenue Bond Investments Segment [Member]
Total revenues
Total revenues									49,100,423	36,673,232	38,772,872
Interest expense
Interest expense									18,705,398	11,904,616	10,787,252
Income from continuing operations
Income from continuing operations									15,438,583	11,755,639	17,924,037
Partnership Net income
Partnership Net income									15,438,583	11,755,639	17,924,037
Total assets
Total assets	937,565,390				764,995,675				937,565,390	764,995,675
Operating Segments [Member] | MF Properties [Member]
Total revenues
Total revenues									13,677,635	17,404,439	17,789,125
Interest expense
Interest expense									2,099,840	2,200,531	2,659,350
Depreciation expense
Depreciation expense									4,949,935	5,980,483	5,888,973
Income from continuing operations
Income from continuing operations									9,739,704	8,442,704	2,964,297
Partnership Net income
Partnership Net income									9,668,051	8,443,527	2,967,098
Total assets
Total assets	83,514,758				129,895,112				83,514,758	129,895,112
Operating Segments [Member] | Public Housing Capital Fund Trusts [Member]
Total revenues
Total revenues									2,951,735	2,888,035	2,994,482
Interest expense
Interest expense									1,350,205	1,349,800	1,221,713
Income from continuing operations
Income from continuing operations									839,570	1,538,234	1,758,022
Partnership Net income
Partnership Net income									839,570	1,538,234	1,758,022
Total assets
Total assets	49,918,434				57,461,268				49,918,434	57,461,268
Operating Segments [Member] | MBS Securities Investments [Member]
Total revenues
Total revenues										17,921	225,890
Interest expense
Interest expense										14,692	157,902
Income from continuing operations
Income from continuing operations										51,984	67,547
Partnership Net income
Partnership Net income										51,984	67,547
Operating Segments [Member] | Other Investments [Member]
Total revenues
Total revenues									4,651,752	1,995,123	170,922
Income from continuing operations
Income from continuing operations									4,644,994	1,995,123	170,922
Partnership Net income
Partnership Net income									4,644,994	1,995,123	170,922
Total assets
Total assets	55,573,834				34,540,280				55,573,834	34,540,280
Operating Segments [Member] | Discontinued Operations [Member]
Partnership Net income
Partnership Net income											$ 3,721,397
Consolidation, Eliminations [Member]
Total assets
Total assets	$ (56,804,417)				$ (42,778,661)				$ (56,804,417)	$ (42,778,661)