Consolidated Statements of Partners' Capital - USD ($)	Total	General Partner	Number of Units	Limited Partner [Member]	Unallocated Deficit of Consolidated VIEs	Noncontrolling Interest	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2014	$ 309,927,904	$ 578,238		$ 330,457,117	$ (21,091,456)	$ (15,995)	$ 51,698,418
Partners' Capital Account, Units at Dec. 31, 2014			60,252,928
Distributions paid or accrued	(7,607,693)	(76,077)		(7,531,616)
Net income (loss) allocated to Partners and noncontrolling interests:
Net income (loss)	2,523,588	26,706		2,643,939	(146,166)	(891)	2,523,588
Unrealized gain (loss) on securities	(1,057,235)	(10,572)		(1,046,663)			(1,057,235)
Unrealized gain (loss) on bond purchase commitment	(576,225)	(5,762)		(570,463)			(576,225)
Balance at Mar. 31, 2015	303,210,339	512,533		323,952,314	$ (21,237,622)	(16,886)	50,064,958
Partners' Capital Account, Units at Mar. 31, 2015			60,252,928
Balance at Dec. 31, 2015	313,124,827	399,077		312,720,264		5,486	60,963,687
Partners' Capital Account, Units at Dec. 31, 2015			60,252,928
Reversal of net unrealized gain on sale of securities	(236,439)	(2,364)		(234,075)			(236,439)
Distributions paid or accrued	(7,607,693)	(76,077)		(7,531,616)
Net income (loss) allocated to Partners and noncontrolling interests:
Redeemable Series A Preferred Unit distribution accrued and accretion	(1,684)	(17)		(1,667)
Net income (loss)	2,531,688	67,172		2,464,528		(12)	2,531,688
Unrealized gain (loss) on securities	12,337,427	123,374		12,214,053			12,337,427
Unrealized gain (loss) on bond purchase commitment	1,587,813	15,878		1,571,935			1,587,813
Balance at Mar. 31, 2016	$ 321,735,939	$ 527,043		$ 321,203,422		$ 5,474	$ 74,652,488
Partners' Capital Account, Units at Mar. 31, 2016			60,252,928