Consolidated Statements of Partners' Capital - USD ($)	Total	Tier 2 [Member]	Tier 3 [Member]	General Partner [Member]	General Partner [Member] Tier 2 [Member]	BUCs - Restricted and Unrestricted [Member]	BUCs - Restricted and Unrestricted [Member] Tier 2 [Member]	BUCs - Restricted and Unrestricted [Member] Tier 3 [Member]	Number of BUCs - Restricted and Unrestricted [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2019	$ 341,938,263			$ 735,128		$ 341,203,135				$ 99,308,677
Partners' Capital Account, Units at Dec. 31, 2019									60,835,204
Distributions paid or accrued:
Regular distribution	(19,110,367)			(191,104)		(18,919,263)
Distribution of (income) loss (Note 3)		$ 445,719			$ 80,501		$ 365,218
Net income (loss) allocable to Partners	4,337,777			(32,666)		4,370,443
Repurchase of BUCs, Value	(2,106,673)					(2,106,673)
Repurchase of BUCs, Units									(290,000)
Restricted units awarded									290,000
Restricted unit compensation expense	1,017,938			10,179		1,007,759
Restricted units forfeited									(2,802)
BUCs surrendered to pay tax withholding on vested restricted units	(35,945)					(35,945)
BUCs surrendered to pay tax withholding on vested restricted units, Units									(8,728)
Unrealized gain (loss) on securities	33,609,375			336,094		33,273,281				33,609,375
Unrealized gain on bond purchase commitments	431,879			4,319		427,560				431,879
Reversal of net unrealized gains on sale of securities	(1,408,804)			(14,088)		(1,394,716)				(1,408,804)
Reversal of net unrealized loss on securities to provision for credit loss	652,880			6,529		646,351				652,880
Balance at Dec. 31, 2020	359,772,042			934,892		358,837,150				132,594,007
Partners' Capital Account, Units at Dec. 31, 2020									60,823,674
Distributions paid or accrued:
Regular distribution	(17,782,023)			(177,820)		(17,604,203)
Distribution of (income) loss (Note 3)		$ (10,596,968)	$ (6,507,605)		$ (2,649,242)		$ (7,947,726)	$ (6,507,605)
Net income (loss) allocable to Partners	35,228,437			2,830,481		32,397,956
Sale of BUCs, net of issuance costs, Value	31,239,495					31,239,495
Sale of BUCs, net of issuance costs, Units									5,462,500
Repurchase of BUCs, Value	(1,363,736)					(1,363,736)
Repurchase of BUCs, Units									(222,459)
Restricted units awarded									266,324
Restricted unit compensation expense	1,277,694			12,777		1,264,917
BUCs surrendered to pay tax withholding on vested restricted units	(301,562)					(301,562)
BUCs surrendered to pay tax withholding on vested restricted units, Units									(47,565)
Unrealized gain (loss) on securities	(19,086,272)			(190,863)		(18,895,409)				(19,086,272)
Unrealized gain on bond purchase commitments	532,525			5,325		527,200				532,525
Balance at Dec. 31, 2021	$ 372,412,027			$ 765,550		$ 371,646,477				$ 114,040,260
Partners' Capital Account, Units at Dec. 31, 2021									66,282,474