Investments in Mortgage Revenue Bonds Investments in Mortgage Revenue Bonds(Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	$ 386,280,003		$ 338,861,752
Cost adjusted for pay-downs	76,919,779		65,538,068
Unrealized Gain, held in trust	39,742,844		39,561,340
Unrealized Gain	4,973,588		5,082,559
Unrealized Loss, held in trust	0		0
Unrealized Loss	(17,516)		(19,582)
Estimated Fair Value, held in trust	426,022,847		378,423,092
Estimated Fair Value	81,875,851		70,601,045
Arbors at Hickory Ridge [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	11,569,614	[1]	11,570,933	[1]
Unrealized Gain, held in trust	1,239,453	[1]	1,792,303	[1]
Unrealized Loss, held in trust	0	[1]	0	[1]
Estimated Fair Value, held in trust	12,809,067	[1]	13,363,236	[1]
Ashley Square [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	5,144,000	[2]	5,159,000	[2]
Unrealized Gain, held in trust	498,269	[2]	486,559	[2]
Unrealized Loss, held in trust	0	[2]	0	[2]
Estimated Fair Value, held in trust	5,642,269	[2]	5,645,559	[2]
Avistar on the Hills [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust			5,389,000	[1]
Unrealized Gain, held in trust			743,520	[1]
Unrealized Loss, held in trust			0	[1]
Estimated Fair Value, held in trust			6,132,520	[1]
Bella Vista [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	6,490,000	[2]	6,490,000	[2]
Unrealized Gain, held in trust	573,067	[2]	625,571	[2]
Unrealized Loss, held in trust	0	[2]	0	[2]
Estimated Fair Value, held in trust	7,063,067	[2]	7,115,571	[2]
Bridle Ridge [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	7,625,000	[2]	7,655,000	[2]
Unrealized Gain, held in trust	595,665	[2]	659,249	[2]
Unrealized Loss, held in trust	0	[2]	0	[2]
Estimated Fair Value, held in trust	8,220,665	[2]	8,314,249	[2]
Brookstone [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	7,469,357	[2]	7,468,888	[2]
Unrealized Gain, held in trust	1,652,619	[2]	1,360,589	[2]
Unrealized Loss, held in trust	0	[2]	0	[2]
Estimated Fair Value, held in trust	9,121,976	[2]	8,829,477	[2]
Bruton Apts [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust			18,145,000	[3]
Unrealized Gain, held in trust			1,455,955	[3]
Unrealized Loss, held in trust			0	[3]
Estimated Fair Value, held in trust			19,600,955	[3]
Bruton Apartments [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	18,145,000	[3]
Unrealized Gain, held in trust	1,298,819	[3]
Unrealized Loss, held in trust	0	[3]
Estimated Fair Value, held in trust	19,443,819	[3]
Glenview Apts [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	6,723,000		6,723,000
Unrealized Gain	132,286		0
Unrealized Loss	0		0
Estimated Fair Value	6,855,286		6,723,000
Copper Gate [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	5,220,000	[1]	5,220,000	[1]
Unrealized Gain, held in trust	390,143	[1]	563,656	[1]
Unrealized Loss, held in trust	0	[1]	0	[1]
Estimated Fair Value, held in trust	5,610,143	[1]	5,783,656	[1]
Cross Creek [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	6,082,064	[2]	6,074,817	[2]
Unrealized Gain, held in trust	2,465,384	[2]	2,542,262	[2]
Unrealized Loss, held in trust	0	[2]	0	[2]
Estimated Fair Value, held in trust	8,547,448	[2]	8,617,079	[2]
Decatur-Angle [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	23,000,000	[3]	23,000,000	[3]
Unrealized Gain, held in trust	727,260	[3]	919,540	[3]
Unrealized Loss, held in trust	0	[3]	0	[3]
Estimated Fair Value, held in trust	23,727,260	[3]	23,919,540	[3]
Heritage Square [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	11,705,000		11,705,000
Unrealized Gain	295,073		1,109,125
Unrealized Loss	0		0
Estimated Fair Value	12,000,073		12,814,125
Montclair Apts [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	3,458,000		3,458,000
Unrealized Gain	148,478		0
Unrealized Loss	0		0
Estimated Fair Value	3,606,478		3,458,000
Lake Forest [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	8,856,000	[2]	8,886,000	[2]
Unrealized Gain, held in trust	1,037,354	[2]	1,003,614	[2]
Unrealized Loss, held in trust	0	[2]	0	[2]
Estimated Fair Value, held in trust	9,893,354	[2]	9,889,614	[2]
Live 929 Apartments [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	40,874,690	[3]	40,895,739	[3]
Unrealized Gain, held in trust	4,154,777	[3]	3,797,745	[3]
Unrealized Loss, held in trust	0	[3]	0	[3]
Estimated Fair Value, held in trust	45,029,467	[3]	44,693,484	[3]
Pro Nova [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	20,092,423	[3]	20,095,169	[3]
Unrealized Gain, held in trust	889,777	[3]	1,043,431	[3]
Unrealized Loss, held in trust	0	[3]	0	[3]
Estimated Fair Value, held in trust	20,982,200	[3]	21,138,600	[3]
Rennaisance [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	12,675,000		12,675,000
Unrealized Gain	762,823		1,055,807
Unrealized Loss	0		0
Estimated Fair Value	13,437,823		13,730,807
Santa Fe Apts [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	4,736,000		4,736,000
Unrealized Gain	120,631		0
Unrealized Loss	0		0
Estimated Fair Value	4,856,631		4,736,000
Runnymede [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	10,440,000	[2]	10,440,000	[2]
Unrealized Gain, held in trust	1,297,483	[2]	1,385,910	[2]
Unrealized Loss, held in trust	0	[2]	0	[2]
Estimated Fair Value, held in trust	11,737,483	[2]	11,825,910	[2]
Southpark [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	11,861,623	[2]	11,842,206	[2]
Unrealized Gain, held in trust	3,599,239	[2]	3,743,692	[2]
Unrealized Loss, held in trust	0	[2]	0	[2]
Estimated Fair Value, held in trust	15,460,862	[2]	15,585,898	[2]
The Palms at Premier Park [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	20,125,232	[1]	20,152,000	[1]
Unrealized Gain, held in trust	2,005,005	[1]	2,680,619	[1]
Unrealized Loss, held in trust	0	[1]	0	[1]
Estimated Fair Value, held in trust	22,130,237	[1]	22,832,619	[1]
The Suites on Paseo [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	35,450,000	[3]	35,450,000	[3]
Unrealized Gain, held in trust	2,901,583	[3]	3,193,691	[3]
Unrealized Loss, held in trust	0	[3]	0	[3]
Estimated Fair Value, held in trust	38,351,583	[3]	38,643,691	[3]
Vantage at Harlingen [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	6,692,000		6,692,000
Unrealized Gain	260,386		707,813
Unrealized Loss	0		0
Estimated Fair Value	6,952,386		7,399,813
Vantage at Judson [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	6,049,000		6,049,000
Unrealized Gain	485,432		717,230
Unrealized Loss	0		0
Estimated Fair Value	6,534,432		6,766,230
Woodlynn Village [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	4,390,000	[2]	4,390,000	[2]
Unrealized Gain, held in trust	244,962	[2]	376,706	[2]
Unrealized Loss, held in trust	0	[2]	0	[2]
Estimated Fair Value, held in trust	4,634,962	[2]	4,766,706	[2]
Series A [Member] | Avistar at Chase Hill [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	10,000,000	[1]	10,000,000	[1]
Unrealized Gain, held in trust	1,226,837	[1]	1,196,800	[1]
Unrealized Loss, held in trust	0	[1]	0	[1]
Estimated Fair Value, held in trust	11,226,837	[1]	11,196,800	[1]
Series A [Member] | Avistar at the Crest [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	9,700,000	[1]	9,700,000	[1]
Unrealized Gain, held in trust	1,054,230	[1]	1,419,692	[1]
Unrealized Loss, held in trust	0	[1]	0	[1]
Estimated Fair Value, held in trust	10,754,230	[1]	11,119,692	[1]
Series A [Member] | Avistar at the Oaks [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	7,800,000	[1]	7,800,000	[1]
Unrealized Gain, held in trust	802,611	[1]	869,622	[1]
Unrealized Loss, held in trust	0	[1]	0	[1]
Estimated Fair Value, held in trust	8,602,611	[1]	8,669,622	[1]
Series A [Member] | Avistar in 09 [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	6,735,000	[1]	6,735,000	[1]
Unrealized Gain, held in trust	787,493	[1]	750,885	[1]
Unrealized Loss, held in trust	0	[1]	0	[1]
Estimated Fair Value, held in trust	7,522,493	[1]	7,485,885	[1]
Series A [Member] | Avistar on the Boulevard [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	16,525,000	[1]	16,525,000	[1]
Unrealized Gain, held in trust	1,795,997	[1]	2,418,599	[1]
Unrealized Loss, held in trust	0	[1]	0	[1]
Estimated Fair Value, held in trust	18,320,997	[1]	18,943,599	[1]
Series A [Member] | Avistar on the Hills [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	5,389,000	[1]
Unrealized Gain, held in trust	554,521	[1]
Unrealized Loss, held in trust	0	[1]
Estimated Fair Value, held in trust	5,943,521	[1]
Series A [Member] | Concord at Gulfgate [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	17,060,000	[3]
Cost adjusted for pay-downs	17,100,000
Unrealized Gain, held in trust	1,417,004	[3]
Unrealized Loss, held in trust	0	[3]
Estimated Fair Value, held in trust	18,477,004	[3]
Series A [Member] | Concord at Little York [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	12,480,000	[3]
Cost adjusted for pay-downs	12,500,000
Unrealized Gain, held in trust	820,061	[3]
Unrealized Loss, held in trust	0	[3]
Estimated Fair Value, held in trust	13,300,061	[3]
Series A [Member] | Concord at Williamcrest [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	18,020,000	[3]
Cost adjusted for pay-downs	18,000,000
Unrealized Gain, held in trust	1,184,094	[3]
Unrealized Loss, held in trust	0	[3]
Estimated Fair Value, held in trust	19,204,094	[3]
Series A [Member] | Greens of Pine Glen [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	8,348,000	[1]	8,366,000	[1]
Unrealized Gain, held in trust	943,736	[1]	1,005,119	[1]
Unrealized Loss, held in trust	0	[1]	0	[1]
Estimated Fair Value, held in trust	9,291,736	[1]	9,371,119	[1]
Series A [Member] | Harden Ranch [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	6,960,000	[1]	6,960,000	[1]
Unrealized Gain, held in trust	623,129	[1]	511,421	[1]
Unrealized Loss, held in trust	0	[1]	0	[1]
Estimated Fair Value, held in trust	7,583,129	[1]	7,471,421	[1]
Series A [Member] | Ohio Properties [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	14,383,000	[2]	14,407,000	[2]
Unrealized Gain, held in trust	2,328,438	[2]	2,444,034	[2]
Unrealized Loss, held in trust	0	[2]	0	[2]
Estimated Fair Value, held in trust	16,711,438	[2]	16,851,034	[2]
Series A [Member] | Tyler Park Apartments [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	6,075,000	[1]	6,075,000	[1]
Unrealized Gain, held in trust	383,329	[1]	345,060	[1]
Unrealized Loss, held in trust	0	[1]	0	[1]
Estimated Fair Value, held in trust	6,458,329	[1]	6,420,060	[1]
Series A [Member] | Westside Village Market [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs, held in trust	3,970,000	[1]	3,970,000	[1]
Unrealized Gain, held in trust	250,505	[1]	225,496	[1]
Unrealized Loss, held in trust	0	[1]	0	[1]
Estimated Fair Value, held in trust	4,220,505	[1]	4,195,496	[1]
Series B [Member] | Avistar at Chase Hill [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	965,000		965,000
Unrealized Gain	88,486		144,769
Unrealized Loss	0		0
Estimated Fair Value	1,053,486		1,109,769
Series B [Member] | Avistar at the Crest [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	759,000		759,000
Unrealized Gain	69,600		124,286
Unrealized Loss	0		0
Estimated Fair Value	828,600		883,286
Series B [Member] | Avistar at the Oaks [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	554,000		554,000
Unrealized Gain	50,841		54,325
Unrealized Loss	0		0
Estimated Fair Value	604,841		608,325
Series B [Member] | Avistar in 09 [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	457,000		457,000
Unrealized Gain	41,939		50,608
Unrealized Loss	0		0
Estimated Fair Value	498,939		507,608
Series B [Member] | Avistar on the Boulevard [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	451,000		451,000
Unrealized Gain	41,357		73,851
Unrealized Loss	0		0
Estimated Fair Value	492,357		524,851
Series B [Member] | Concord at Gulfgate [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	2,125,000
Unrealized Gain	592,323
Unrealized Loss	0
Estimated Fair Value	2,717,323
Series B [Member] | Concord at Little York [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	960,000
Unrealized Gain	252,586
Unrealized Loss	0
Estimated Fair Value	1,212,586
Series B [Member] | Concord at Williamcrest [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	2,800,000
Unrealized Gain	736,708
Unrealized Loss	0
Estimated Fair Value	3,536,708
Series B [Member] | Greens of Pine Glen [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	945,059		945,638
Unrealized Gain	249,820		376,203
Unrealized Loss	0		0
Estimated Fair Value	1,194,879		1,321,841
Series B [Member] | Harden Ranch [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	2,340,000		2,340,000
Unrealized Gain	0		0
Unrealized Loss	(2,176)		(1,501)
Estimated Fair Value	2,337,824		2,338,499
Series B [Member] | Ohio Properties [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	3,570,720		3,573,430
Unrealized Gain	644,819		668,542
Unrealized Loss	0		0
Estimated Fair Value	4,215,539		4,241,972
Series B [Member] | The Suites on Paseo [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	5,500,000
Unrealized Gain	0
Unrealized Loss	0
Estimated Fair Value	5,500,000
Series B [Member] | Tyler Park Apartments [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	2,025,000		2,025,000
Unrealized Gain	0		0
Unrealized Loss	(8,991)		(17,395)
Estimated Fair Value	2,016,009		2,007,605
Series B [Member] | Westside Village Market [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost adjusted for pay-downs	1,430,000		1,430,000
Unrealized Gain	0		0
Unrealized Loss	(6,349)		(686)
Estimated Fair Value	$ 1,423,651		$ 1,429,314

[1] Mortgage revenue bonds owned by ATAX TEBS II, LLC, Note 9

[2] Mortgage revenue bonds owned by ATAX TEBS I, LLC, Note 9

[3] Mortgage revenue bonds held by Deutsche Bank in a secured financing transaction, Note 9