Investment in Joint Venture (Components of Income from Discontinued Operations Recognized by Joint Ventures) (Details) (Fund VIII-IX Associates, USD $)	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Fund VIII-IX Associates
Schedule of Equity Method Investments [Line Items]
Operating Income	$ 97,707	$ 82,654
Gain on Sale	2,015,591	0
Total	$ 2,113,298	$ 82,654

This item represents the amount of gain (loss) arising from the disposal of an equity method investment.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration