Investment in Joint Ventures Partnership's investments (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Joint Venture Activities [Roll Forward]
Investment in Joint Ventures, beginning of year				$ 4,109,865					$ 4,109,865
Equity in income of Joint Ventures	970,663	(58,561)	(54,507)	885,403	(4,588)	3,269	79,832	75,814	1,742,998	154,327	720,494
Contributions to Joint Ventures									368,065	0	253,699
Distributions from Joint Ventures									(27,074)	(389,332)	(519,835)
Investments in Joint Ventures, end of year	0				4,109,865				0	4,109,865
Fund VIII-IX Associates
Schedule of Equity Method Investments [Line Items]
Ownership in joint venture (percent)	45.20%				45.20%				45.20%	45.20%
Joint Venture Activities [Roll Forward]
Investments in Joint Ventures, end of year	0				4,109,865				0	4,109,865
Joint Ventures
Joint Venture Activities [Roll Forward]
Investment in Joint Ventures, beginning of year				4,109,865				4,239,485	4,109,865	4,239,485
Equity in income of Joint Ventures									1,742,998	154,327
Contributions to Joint Ventures									368,065	0
Distributions from Joint Ventures									(6,220,928)	(283,947)
Investments in Joint Ventures, end of year	$ 0				$ 4,109,865				$ 0	$ 4,109,865