Property Transactions (Details 1) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Components of Income (Loss) from Discontinued Operations
Rental property revenues	$ 309,000	$ 3,614,000
Rental property operating expenses	(85,000)	(1,371,000)
Depreciation and amortization	(120,000)	(1,426,000)
Income from discontinued operations	104,000	817,000
Gain (loss) on sale of investment properties	86,000	(384,000)
Galleria Seventy Five Suburban Atlanta [Member]
Components of Income (Loss) from Discontinued Operations
Square Footage of Real Estate Property	111,000
Jefferson Mill Business Park Building A [Member]
Components of Income (Loss) from Discontinued Operations
Gain (loss) on sale of investment properties	0	(394,000)
Square Footage of Real Estate Property		459,000
Sales Price of Property Sold Discontinued Operations		22,000,000
Other [Member]
Components of Income (Loss) from Discontinued Operations
Gain (loss) on sale of investment properties	$ 86,000	$ 10,000