Property Transactions (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Components of Income (Loss) from Discontinued Operations
Rental property revenues	$ 5,055,000	$ 10,519,000	$ 18,969,000	$ 31,720,000
Third Party Management and Leasing Revenues	4,789,000	5,398,000	15,528,000	14,091,000
Discontinued Operations Other Income	267,000	1,000	472,000	115,000
Rental property operating expenses	(1,508,000)	(4,391,000)	(6,001,000)	(12,237,000)
Third Party Management and Leasing Expenses	(4,260,000)	(4,241,000)	(13,167,000)	(12,414,000)
Depreciation and amortization	(2,575,000)	(4,650,000)	(8,622,000)	(14,721,000)
Impairment of Real Estate			(12,233,000)
Discontinued Operations Other Expense	(8,000)	(17,000)	(39,000)	(51,000)
Income from discontinued operations	1,760,000	2,619,000	(5,093,000)	6,503,000
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	7,444,000	2,821,000	8,204,000	2,437,000
The Avenue Collierville [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price of Property Sold Discontinued Operations			55,000,000
Area of Real Estate Property	511,000		511,000
Galleria 75 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price of Property Sold Discontinued Operations			9,200,000
Area of Real Estate Property	111,000		111,000
Components of Income (Loss) from Discontinued Operations
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	0	0	547,000	0
One Georgia Center Atlanta [Member]
Components of Income (Loss) from Discontinued Operations
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	0	2,821,000	0	2,821,000
Cosmopolitan Center [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price of Property Sold Discontinued Operations			7,000,000
Jefferson Mill Business Park Building A [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price of Property Sold Discontinued Operations				22,000,000
Area of Real Estate Property		459,000		459,000
Components of Income (Loss) from Discontinued Operations
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	0	0	0	(394,000)
Third Party Management [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Potential Proceeds from Sale	15,400,000
Percentage of Sales Proceeds Received at Closing	63.50%
Components of Income (Loss) from Discontinued Operations
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	7,384,000	0	7,384,000	0
Other [Member]
Components of Income (Loss) from Discontinued Operations
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	$ 60,000	$ 0	$ 273,000	$ 10,000