Commitments and Contingencies Vantage at Judson (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Available-for-sale Securities, at Par Value	$ 146,806,203	$ 145,907,502
Vantage at Judson [Member]
Available-for-sale Securities, at Par Value	6,049,000
Series C [Member] \| Vantage at Judson [Member]
Available-for-sale Securities, at Par Value	6,049,000
Series B [Member] \| Vantage at Judson [Member]
Available-for-sale Securities, at Par Value	26,687,000
Available-for-sale Securities	20,638,000
Series D [Member] \| Vantage at Judson [Member]
Available-for-sale Securities, at Par Value	$ 934,000

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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+ Details