Property Transactions Property Transactions (Discontinued Operations) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Discontinued Operations [Line Items]
Document Fiscal Year Focus			2013
Income (Loss) from Discontinued Operations	$ 803	$ 4,724	$ 1,394	$ (1,087)
Gain (Loss) on Disposal of Discontinued Operation	8,346	7,444	8,527	8,204
Segment, Discontinued Operations [Member]
Discontinued Operations [Line Items]
Rental property revenues	1,237	6,522	3,924	23,468
Fee Income	0	4,789	76	15,529
Other Income	10	3,242	10	3,447
Rental property operating expenses	(423)	(1,962)	(1,470)	(7,280)
Reimbursed Expenses	0	(2,477)	0	(7,133)
General and Administrative Expense	(15)	(1,782)	(94)	(6,035)
Depreciation and amortization	0	(3,600)	(1,033)	(10,810)
Impairment of Real Estate	0	0	0	(12,233)
Discontinued Operations Other Expense	(6)	(8)	(19)	(40)
Income (Loss) from Discontinued Operations	803	4,724	1,394	(1,087)
Third Party Management [Member]
Discontinued Operations [Line Items]
Gain (Loss) on Disposal of Discontinued Operation	4,531	7,384	4,531	7,384
Tiffany Springs MarketCenter Kansas City [Member]
Discontinued Operations [Line Items]
Gain (Loss) on Disposal of Discontinued Operation	3,715	0	3,715	0
Lakeside Ranch Business Park Dallas [Member]
Discontinued Operations [Line Items]
Gain (Loss) on Disposal of Discontinued Operation	62	(9)	62	(60)
King Mill Distribution Park Building Three [Member]
Discontinued Operations [Line Items]
Gain (Loss) on Disposal of Discontinued Operation	38	89	246	264
Galleria 75 [Member]
Discontinued Operations [Line Items]
Gain (Loss) on Disposal of Discontinued Operation	0	0	0	546
The Avenue Collierville [Member]
Discontinued Operations [Line Items]
Gain (Loss) on Disposal of Discontinued Operation	0	(20)	0	66
Other Discontinued Operations [Member]
Discontinued Operations [Line Items]
Gain (Loss) on Disposal of Discontinued Operation	$ 0	$ 0	$ (27)	$ 4