Fair Value Measurements Fair Value Level 3 Rollforward (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				3 Months Ended		1 Months Ended	12 Months Ended		3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Mar. 31, 2014 Fair Value, Inputs, Level 3 [Member]	Mar. 31, 2014 Lakeshore Mall [Member]	Dec. 31, 2013 Lakeshore Mall [Member]	Apr. 30, 2014 Lakeshore Mall [Member] Subsequent event [Member]	Mar. 31, 2014 Lakeshore Mall [Member] Revenues [Member]	Apr. 30, 2014 Lakeshore Mall [Member] Fair Value, Inputs, Level 3 [Member] Subsequent event [Member]	Mar. 31, 2014 Chapel Hill Mall [Member]	Dec. 31, 2013 Chapel Hill Mall [Member]	Mar. 31, 2014 Chapel Hill Mall [Member] Revenues [Member]	Mar. 31, 2014 Chapel Hill Mall [Member] Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of investments In real estate	$ 67,128			$ 67,128					$ 13,780				$ 53,348
Concentration risk, percentage								0.40%				1.00%
Long-lived Assets, Real Estate [Roll Forward]
Beginning carrying value	67,128		85,189		13,780	19,127				53,348	66,062
Capital expenditures	11				11					0
Depreciation expense	(922)				(258)					(664)
Loss on impairment of real estate	(17,150)	0			(5,100)		(5,100)			(12,050)
Ending carrying value	$ 67,128		$ 85,189		$ 13,780	$ 19,127				$ 53,348	$ 66,062