Investments in Partnerships - Pending and Completed Sales (Details) (USD $)	3 Months Ended		9 Months Ended			9 Months Ended				0 Months Ended	3 Months Ended	9 Months Ended	0 Months Ended			12 Months Ended		0 Months Ended		3 Months Ended	9 Months Ended		0 Months Ended	3 Months Ended	0 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 Local Partnerships [Member]	Dec. 31, 2012 Local Partnerships [Member]	Sep. 30, 2013 Westport Village [Member]	Dec. 31, 2012 Westport Village [Member]	Sep. 10, 2013 Tradewinds West Limited Dividend Housing Association Limited Partnership [Member]	Sep. 30, 2013 Tradewinds West Limited Dividend Housing Association Limited Partnership [Member]	Sep. 30, 2013 Tradewinds West Limited Dividend Housing Association Limited Partnership [Member]	Dec. 31, 2012 Fairway Park [Member]	Dec. 20, 2012 Fairway Park [Member]	Oct. 26, 2012 Fairway Park [Member]	Dec. 31, 2012 Fairway Park [Member]	Dec. 31, 2011 Mary Allen West Tower [Member]	Aug. 26, 2013 Northridge Park [Member]	Mar. 04, 2013 Northridge Park [Member]	Sep. 30, 2013 Northridge Park [Member]	Sep. 30, 2013 Northridge Park [Member]	Dec. 31, 2012 Northridge Park [Member]	Dec. 20, 2012 CRI, Inc [Member] Fairway Park [Member]	Sep. 30, 2012 CRI, Inc [Member] Mary Allen West Tower [Member]	Aug. 26, 2013 CRI, Inc [Member] Northridge Park [Member]	Oct. 22, 2013 Subsequent Event [Member] Tradewinds West Limited Dividend Housing Association Limited Partnership [Member]
Schedule of Equity Method Investments [Line Items]
Basis in Partnership	$ 399,835		$ 399,835		$ 1,246,665	$ 399,835	$ 1,246,665	$ 0	$ 0		$ 1,174,235	$ 1,174,235						$ 0				$ 0
Impairment loss	774,400	0	774,400	0		774,400					774,400	774,400
Property sale price										399,835					8,710,000				10,250,000
Sale proceeds														8,710,000				5,891,674								399,835
Actual cash received after loan payoff																		2,406,619
Net unamortized acquisition fees and property purchase costs																		13,654
Basis in Partnership after sale													0				4,767,709
Acquisition fee	5,913		5,913		15,254								8,294			8,294
Property purchase cost	6,165		6,165		12,170								4,130			4,130
Gain on disposition of investment																8,282,016				5,673,020	5,673,020
Fee for services provided in connection with sale																							$ 415,560	$ 70,000	$ 205,000