Debt Financing Footnote XBRL details (Details) (USD $)	Jun. 30, 2012	Dec. 31, 2011	Jul. 31, 2011 Autumn Pines [Member]	Jul. 31, 2011 GMF-Warren/Tulane [Member]	Jun. 30, 2012 TOB Facility-1 [Member]	Jun. 30, 2012 TEB Facility [Member] Integer	Dec. 31, 2010 Class A TEBS Certificates [Member] TEB Facility [Member]	Dec. 31, 2010 Class B TEBS Certificates [Member] TEB Facility [Member]
Debt financing	$ 104,328,000	$ 112,673,000				$ 94,400,000	$ 95,800,000	$ 20,300,000
TOB Financing	9,900,000	17,700,000	10,000,000	7,800,000
Available for Sale Securities at Par Value	$ 124,074,368	$ 124,648,502	$ 13,400,000	$ 15,600,000
Debt Instrument, Basis Spread on Variable Rate					1.77%	1.90%
Debt Instrument, Interest Rate, Stated Percentage					0.27%	0.23%
Debt, Weighted Average Interest Rate					2.04%	2.13%
Number of Available for Sale Securities, Held in a Trust						13