Debt Financing Debt Financing (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	$ 118,297,232		$ 118,342,000
TEB Facility [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	103,332,167		103,516,998
TEB Facility [Member] | Ashley Square [Member] | Mortgage revenue bonds [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	5,144,000		5,159,000
TEB Facility [Member] | Bella Vista [Member] | Mortgage revenue bonds [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	6,490,000		6,490,000
TEB Facility [Member] | Bent Tree [Member] | Consolidated VIEs [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	7,444,000		7,465,000
TEB Facility [Member] | Bridle Ridge [Member] | Mortgage revenue bonds [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	7,625,000		7,655,000
TEB Facility [Member] | Brookstone [Member] | Mortgage revenue bonds [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	9,234,633		9,256,001
TEB Facility [Member] | Cross Creek [Member] | Mortgage revenue bonds [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	8,403,534		8,422,997
TEB Facility [Member] | Fairmont Oaks [Member] | Consolidated VIEs [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	7,242,000		7,266,000
TEB Facility [Member] | Lake Forest [Member] | Mortgage revenue bonds [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	8,856,000		8,886,000
TEB Facility [Member] | Runnymede [Member] | Mortgage revenue bonds [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	10,440,000		10,440,000
TEB Facility [Member] | Southpark [Member] | Mortgage revenue bonds [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	13,680,000		13,680,000
TEB Facility [Member] | Woodlynn Village [Member] | Mortgage revenue bonds [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	4,390,000		4,390,000
TEB Facility [Member] | Series A [Member] | Ohio Properties [Member] | Mortgage revenue bonds [Member]
Debt Instrument [Line Items]
Available for Sale Securities at Par Value	$ 14,383,000	[1]	$ 14,407,000	[1]

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