Summary of Activity Related to Level 3 Assets and Liabilities (Details) - Fair Value, Inputs, Level 3 [Member] - USD ($)		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Schedule of Available-for-sale Securities [Line Items]
Assets at Fair Value, beginning balance		$ 820,480,265	$ 666,958,282	$ 742,897,488	$ 653,875,949
Total gains (losses) (realized/unrealized) [Abstract]
Total gain (losses) included in earnings (interest income and interest expense)		(142,314)	(531,389)	(227,896)	(1,641,796)
Total gain (losses) included in other comprehensive (loss) income		10,771,467	69,830,975	29,972,777	83,756,215
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		496,800		60,081,800	11,500,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sale of securities					(9,747,523)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		(1,350,194)	(5,782,483)	(2,468,145)	(7,267,459)
Assets at Fair Value, ending balance		830,256,024	730,475,386	830,256,024	730,475,386
Total amount of losses for the period included in earnings attributable to the change in unrealized losses relating to assets or liabilities held		(181,420)	(531,389)	(302,769)	(1,641,796)
Interest rate derivatives [Member]
Schedule of Available-for-sale Securities [Line Items]
Liabilities at Fair value, beginning balance	[1]	(1,077,028)	(2,083,704)	(955,679)	(972,898)
Total gains (losses) (realized/unrealized) [Abstract]
Total gain (losses) included in earnings (interest income and interest expense)	[1]	(181,420)	(531,389)	(302,769)	(1,641,796)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	496,800		496,800
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sale of securities	[1]				(399)
Liabilities at Fair value, ending balance	[1]	(761,648)	(2,615,093)	(761,648)	(2,615,093)
Total amount of losses for the period included in earnings attributable to the change in unrealized losses relating to assets or liabilities held	[1]	(181,420)	(531,389)	(302,769)	(1,641,796)
Bond Purchase Commitment [Member]
Schedule of Available-for-sale Securities [Line Items]
Assets at Fair Value, beginning balance		2,620,393	7,222,173	2,399,449	5,634,360
Total gains (losses) (realized/unrealized) [Abstract]
Total gain (losses) included in other comprehensive (loss) income		544,779	9,996,646	765,723	11,584,459
Assets at Fair Value, ending balance		3,165,172	17,218,819	3,165,172	17,218,819
Taxable Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Assets at Fair Value, beginning balance		4,179,205	4,938,104	4,084,599	4,824,060
Total gains (losses) (realized/unrealized) [Abstract]
Total gain (losses) included in other comprehensive (loss) income		(223,758)	378,861	(125,264)	495,317
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		(23,976)	(22,736)	(27,864)	(25,148)
Assets at Fair Value, ending balance		3,931,471	5,294,229	3,931,471	5,294,229
Public housing capital fund trusts [Member]
Schedule of Available-for-sale Securities [Line Items]
Assets at Fair Value, beginning balance		55,851,799	60,505,340	57,158,068	60,707,290
Total gains (losses) (realized/unrealized) [Abstract]
Total gain (losses) included in earnings (interest income and interest expense)		(14,129)		(31,717)
Total gain (losses) included in other comprehensive (loss) income		390,701	1,688,370	(897,980)	2,557,714
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		(437,000)	(13,651)	(437,000)	(1,084,945)
Assets at Fair Value, ending balance		55,791,371	62,180,059	55,791,371	62,180,059
Mortgage Revenue Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Assets at Fair Value, beginning balance	[2]	758,905,896	596,376,369	680,211,051	583,683,137
Total gains (losses) (realized/unrealized) [Abstract]
Total gain (losses) included in earnings (interest income and interest expense)	[2]	53,235		106,590
Total gain (losses) included in other comprehensive (loss) income	[2]	10,059,745	57,767,098	30,230,298	69,118,725
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[2]			59,585,000	11,500,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sale of securities	[2]				(9,747,124)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[2]	(889,218)	(5,746,096)	(2,003,281)	(6,157,366)
Assets at Fair Value, ending balance	[2]	$ 768,129,658	$ 648,397,372	$ 768,129,658	$ 648,397,372

[1] Interest rate derivatives include derivative contracts reported in other assets as well as derivative swap liabilities.

[2] Mortgage revenue bonds includes both bonds held in trust as well as those held by the Partnership.