Consolidated Statement of Comprehensive Income (Loss) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net income	$ 23,783,684	$ 26,606,222	$ 15,029,188
Reversal of net unrealized gain on sale of securities	(236,439)
Unrealized gain (loss) on bond purchase commitments	(3,234,911)	(146,053)	10,632,590
Comprehensive income	1,715,481	36,502,410	86,855,920
Comprehensive (loss) allocated to noncontrolling interest	(823)	(2,801)	(4,673)
Partnership comprehensive income	1,716,304	36,505,211	86,860,593
Accumulated Other Comprehensive Income (Loss) [Member]
Net income	23,783,684	26,606,222	15,029,188
Reversal of net unrealized gain on sale of securities	(236,439)
Unrealized gain (loss) on securities	(18,596,853)	10,042,241	62,852,308
Net realized (loss) on securities			(1,658,166)
Unrealized gain (loss) on bond purchase commitments	(3,234,911)	(146,053)	10,632,590
Commitments [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Unrealized gain (loss) on bond purchase commitments	$ (3,234,911)	$ (146,053)	$ 10,632,590