Debt Financing (Details) (USD $)	Mar. 31, 2013		Dec. 31, 2012
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	$ 123,469,840		$ 124,648,502
Ashley Square [Member] | Tax-exempt bond investments [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	5,248,000		5,260,000
Bella Vista [Member] | Tax-exempt bond investments [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	6,600,000		6,600,000
Bent Tree [Member] | Consolidated VIEs [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	7,596,000		7,614,000
Bridle Ridge [Member] | Tax-exempt bond investments [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	7,740,000		7,765,000
Brookstone [Member] | Tax-exempt bond investments [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	9,397,647		9,416,794
Cross Creek [Member] | Tax-exempt bond investments [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	8,551,193		8,568,409
Fairmont Oaks [Member] | Consolidated VIEs [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	7,418,000		7,439,000
Lake Forest [Member] | Consolidated VIEs [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	9,078,000		9,105,000
Runnymede [Member] | Tax-exempt bond investments [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	10,605,000		10,605,000
Southpark [Member] | Tax-exempt bond investments [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	13,900,000		13,900,000
Woodlynn Village [Member] | Tax-exempt bond investments [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	4,460,000		4,460,000
Ohio Properties [Member] | Tax-exempt bond investments [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	14,561,000	[1]	14,582,000	[1]
Lost Creek [Member] | Tax-exempt bond investments [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	$ 18,315,000		$ 18,315,000

[1] llateralized by Crescent Village, Postwoods, and Willow Bend (Note 2 and Note 9)T