Other Assets Arbors of Hickory Ridge Loan Receivable (Details) (USD $)	Feb. 28, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Arbors at Hickory Ridge [Member]	Jun. 30, 2012 Arbors at Hickory Ridge [Member]	Dec. 31, 2012 Vantage at Judson [Member]	Dec. 31, 2012 Series D [Member] Vantage at Judson [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Discount Rate for Impairment Analysis		6.50%
Property loan receivable, outstanding balance		$ 20,328,927	$ 19,808,803	$ 191,264	$ 600,000
Debt Instrument, Interest Rate, Stated Percentage	9.00%			6.25%	7.98%	9.00%	9.00%
Available-for-sale Securities, at Par Value		$ 146,806,203	$ 145,907,502	$ 11,450,000	$ 10,000,000	$ 6,049,000	$ 934,000