Investments in Mortgage Revenue Bonds Certain Terms of Mortgage Revenue Bonds (Details) (USD $)			6 Months Ended	12 Months Ended																																																		12 Months Ended										3 Months Ended	12 Months Ended											12 Months Ended				12 Months Ended				3 Months Ended	12 Months Ended		3 Months Ended	12 Months Ended			3 Months Ended	12 Months Ended						12 Months Ended			12 Months Ended			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2012 Arbors at Hickory Ridge [Member]	Dec. 31, 2013 Arbors at Hickory Ridge [Member]		Dec. 31, 2012 Arbors at Hickory Ridge [Member]		Dec. 31, 2013 Ashley Square [Member]		Dec. 31, 2012 Ashley Square [Member]		Dec. 31, 2013 Autumn Pines [Member]		Dec. 31, 2012 Autumn Pines [Member]		Dec. 31, 2013 Bella Vista [Member]		Dec. 31, 2012 Bella Vista [Member]		Dec. 31, 2013 Bridle Ridge [Member]		Dec. 31, 2012 Bridle Ridge [Member]		Dec. 31, 2013 Brookstone [Member]		Dec. 31, 2012 Brookstone [Member]		Dec. 31, 2013 Copper Gate [Member]	Dec. 31, 2012 Cross Creek [Member]		Dec. 31, 2013 Greens of Pine Glen [Member]	Dec. 31, 2012 Greens of Pine Glen [Member]	Dec. 31, 2012 Iona Lakes [Member]		Dec. 31, 2013 Lake Forest [Member]		Dec. 31, 2013 Runnymede [Member]		Dec. 31, 2012 Runnymede [Member]	Dec. 31, 2013 Southpark [Member]		Dec. 31, 2012 Southpark [Member]		Dec. 31, 2013 The Palms at Premier Park [Member]	Dec. 31, 2013 The Suites on Paseo [Member]		Dec. 31, 2013 Vantage at Judson [Member]	Dec. 31, 2012 Vantage at Judson [Member]		Dec. 31, 2013 Vantage at Harlingen [Member]	Dec. 31, 2012 Lost Creek [Member]		Sep. 30, 2013 Woodland Park [Member]	Dec. 31, 2013 Woodlynn Village [Member]		Dec. 31, 2012 Woodlynn Village [Member]		Dec. 31, 2013 Series A [Member] Avistar on the Boulevard [Member]		Dec. 31, 2013 Series A [Member] Avistar at Chase Hill [Member]		Dec. 31, 2013 Series A [Member] Avistar at the Crest [Member]		Mar. 31, 2013 Series A [Member] Avistar Portfolio [Member]	Dec. 31, 2013 Series A [Member] Avistar at the Oaks [Member]		Dec. 31, 2013 Series A [Member] Avistar in 09 [Member]		Dec. 31, 2013 Series A [Member] Avistar on the Hills [Member]		Dec. 31, 2013 Series A [Member] Cross Creek [Member]		Dec. 31, 2013 Series A [Member] Greens of Pine Glen [Member]		Dec. 31, 2012 Series A [Member] Greens of Pine Glen [Member]	Dec. 31, 2013 Series A [Member] Ohio Properties [Member]		Dec. 31, 2013 Series A [Member] Rennaisance [Member]	Jun. 30, 2013 Series A [Member] Rennaisance [Member]	Dec. 31, 2013 Series A [Member] Tyler Park Apartments [Member]	Dec. 31, 2013 Series A [Member] Lost Creek [Member]	Dec. 31, 2012 Series A [Member] Woodland Park [Member]	Dec. 31, 2013 Series A [Member] Westside Village Market [Member]	Mar. 31, 2013 Series C [Member] Avistar Portfolio [Member]	Dec. 31, 2013 Series C [Member] Avistar Portfolio [Member]	Dec. 31, 2013 Series C [Member] Avistar Portolio-2 [Member]	Jun. 30, 2013 Series C [Member] Rennaisance [Member]	Dec. 31, 2013 Series C [Member] Rennaisance [Member]	Dec. 31, 2012 Series C [Member] Vantage at Judson [Member]	Dec. 31, 2013 Series C [Member] Vantage at Harlingen [Member]	Mar. 31, 2013 Series B [Member] Avistar Portfolio [Member]	Dec. 31, 2013 Series B [Member] Avistar Portfolio [Member]	Dec. 31, 2013 Series B [Member] Avistar Portolio-2 [Member]		Dec. 31, 2013 Series B [Member] Greens of Pine Glen [Member]		Dec. 31, 2012 Series B [Member] Greens of Pine Glen [Member]	Dec. 31, 2013 Series B [Member] Ohio Properties [Member]	Dec. 31, 2013 Series B [Member] Rennaisance [Member]	Jun. 30, 2013 Series B [Member] Rennaisance [Member]	Dec. 31, 2013 Series B [Member] Tyler Park Apartments [Member]	Dec. 31, 2013 Series B [Member] Vantage at Judson [Member]	Dec. 31, 2013 Series B [Member] Vantage at Harlingen [Member]	Dec. 31, 2012 Series B [Member] Woodland Park [Member]	Dec. 31, 2013 Series B [Member] Westside Village Market [Member]	Dec. 31, 2013 Available-for-sale Securities [Member]
Available-for-sale Security, Maturity Date at a point in time			Apr. 01, 2026	Dec. 01, 2049	[1]	Dec. 01, 2049	[2]	Dec. 01, 2025	[2]	Dec. 01, 2025	[1]	Oct. 01, 2046	[1]	Oct. 01, 2046	[2]	Apr. 01, 2046	[2]	Apr. 01, 2046	[2]	Jan. 01, 2043	[2]	Jan. 01, 2043	[2]	May 01, 2040	[2]	May 01, 2040	[2]	Dec. 01, 2029	Mar. 01, 2049	[1]	Oct. 01, 2047	Oct. 01, 2047	Apr. 01, 2030	[1]	Dec. 01, 2031	[2]	Oct. 01, 2042	[2]	Oct. 01, 2042	Dec. 01, 2049	[2]	Dec. 01, 2049	[2]	Jan. 01, 2050	Dec. 01, 2048	[1]	Feb. 01, 2053	Feb. 01, 2053	[2]	Oct. 01, 2053	Jun. 01, 2041	[2]		Nov. 01, 2042	[2]	Nov. 01, 2042	[2]	Mar. 01, 2050	[1]	Mar. 01, 2050	[1]	Mar. 01, 2050	[1]	Mar. 01, 2050	Aug. 01, 2050	[1]	Aug. 01, 2050	[1]	Aug. 01, 2050	[1]	Mar. 01, 2049	[2]	Oct. 01, 2047	[1]		Jun. 01, 2050	[1]	Jun. 01, 2050		Jan. 01, 2030	Jun. 01, 2041	Nov. 01, 2047	Jan. 01, 2030	Apr. 01, 2050	Apr. 01, 2050	Sep. 01, 2050	Jun. 01, 2015	Jun. 01, 2015			Apr. 01, 2050	Apr. 01, 2050	Sep. 01, 2050	[1]	Oct. 01, 2047	[1]		Jun. 01, 2050	Jun. 01, 2050		Jan. 01, 2016			Nov. 01, 2047	Jan. 01, 2016
Debt Instrument, Interest Rate, Stated Percentage			7.98%	6.25%	[1]	6.25%	[2]	6.25%	[2]	6.25%	[1]	5.80%	[1]	5.80%	[2]	6.15%	[2]	6.15%	[2]	6.00%	[2]	6.00%	[2]	5.45%	[2]	5.45%	[2]	6.25%	6.15%	[1]			6.90%	[1]	6.25%	[2]	6.00%	[2]	6.00%	6.13%	[2]	6.13%	[2]	6.25%	6.25%	[1]	9.00%	9.00%	[2]	9.00%	6.25%	[2]	2.80%	6.00%	[2]	6.00%	[2]	6.00%	[1]	6.00%	[1]	6.00%	[1]	6.00%	6.00%	[1]	6.00%	[1]	6.00%	[1]	6.15%	[2]	6.50%	[1]	6.50%	7.00%	[1]	6.00%	6.00%	5.75%	6.25%	6.00%	5.75%	9.00%	9.00%	9.00%	12.00%	12.00%		9.00%	9.00%	9.00%	9.00%	[1]	12.00%	[1]	12.00%	10.00%	12.00%	12.00%	5.50%	0.00%	6.00%	8.00%	5.50%	6.00%
Available-for-sale Securities, at Par Value	$ 299,841,918	$ 146,806,203	$ 10,000,000	$ 11,450,000	[1]	$ 11,450,000	[2]	$ 5,212,000	[2]	$ 5,260,000	[1]	$ 13,110,000	[1]	$ 13,220,000	[2]	$ 6,545,000	[2]	$ 6,600,000	[2]	$ 7,715,000	[2]	$ 7,765,000	[2]	$ 9,338,603	[2]	$ 9,416,794	[2]	$ 5,220,000	$ 8,568,409	[1]	$ 9,500,000		$ 15,535,000	[1]	$ 8,997,000	[2]	$ 10,525,000	[2]	$ 10,605,000	$ 13,795,000	[2]	$ 13,900,000	[2]	$ 20,152,000	$ 35,750,000	[1]	$ 6,049,000	$ 6,049,000	[2]	$ 6,692,000	$ 18,315,000	[2]		$ 4,426,000	[2]	$ 4,460,000	[2]	$ 13,760,000	[1]	$ 8,960,000	[1]	$ 8,759,000	[1]		$ 5,878,000	[1]	$ 5,482,000	[1]	$ 3,091,000	[1]	$ 8,497,933	[2]	$ 8,437,501	[1]	$ 8,515,000	$ 14,498,000	[1]	$ 3,850,000		$ 6,075,000	$ 18,090,000	$ 15,013,000	$ 3,970,000	$ 804,000	$ 804,000	$ 831,000	$ 2,900,000	$ 2,875,000	$ 6,000,000	$ 6,700,000		$ 6,921,000	$ 6,484,000	[1]	$ 948,291	[1]	$ 950,000	$ 3,583,590	$ 1,250,000		$ 2,025,000	$ 26,700,000		$ 649,000	$ 1,430,000

[1] Bond held by Deutsche Bank in a secured financing transaction, Note 11

[2] Bonds owned by ATAX TEBS I, LLC, Note 11