Investments in Tax-Exempt Bonds Investments of Tax-Exempt Bonds Villages at Lost Creek (Details) (USD $)	12 Months Ended				6 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Feb. 28, 2013	Jun. 30, 2010 Lost Creek [Member] Unit	Dec. 31, 2012 Lost Creek [Member]		Dec. 31, 2011 Lost Creek [Member]		Dec. 31, 2010 Lost Creek [Member]
Number of Units in Real Estate Property					261
Payments to Acquire Available-for-sale Securities	$ 28,561,857	$ 20,917,500	$ 28,195,363		$ 15,900,000
Available-for-Sale Securities, Asset Ownership					100.00%
Available-for-sale Securities, at Par Value	$ 146,806,203	$ 145,907,502			$ 18,500,000	$ 18,315,000	[1]	$ 18,500,000	[1]
Debt Instrument, Interest Rate, Stated Percentage				9.00%		6.25%	[1]	6.25%	[1]
Debt Instrument, Interest Rate, Effective Percentage										7.55%
Available-for-sale Security, Maturity Date at a point in time						Jun. 01, 2041	[1]	Jun. 01, 2041	[1]

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