Fair Value Measurements - Nonrecurring Basis (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended				3 Months Ended	12 Months Ended		12 Months Ended			12 Months Ended	3 Months Ended	12 Months Ended		12 Months Ended					3 Months Ended			12 Months Ended	3 Months Ended
	Dec. 31, 2013 Properties	Dec. 31, 2012 Properties	Dec. 31, 2011	Dec. 31, 2013 Corporate Airplane [Member]	Dec. 31, 2013 Madison Square Mall [Member]	Dec. 31, 2013 Madison Square Mall [Member]	Dec. 31, 2012 Madison Square Mall [Member]	Dec. 31, 2012 Imperial Valley Commons, L.P. [Member]	Dec. 31, 2013 Imperial Valley Commons, L.P. [Member]	Sep. 30, 2012 Imperial Valley Commons, L.P. [Member]	Dec. 31, 2012 Courtyard at Hickory Hollow [Member]	Jun. 30, 2013 Citadel Mall [Member]	Dec. 31, 2013 Citadel Mall [Member]	Mar. 31, 2013 Citadel Mall [Member]	Dec. 31, 2013 Madison Square and Citadel Mall [Member]	Dec. 31, 2012 Imperial Valley Commons and The Courtyard at Hickory Hollow [Member]	Dec. 31, 2013 Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2013 Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Courtyard at Hickory Hollow [Member]	Sep. 30, 2012 Fair Value, Measurements, Nonrecurring [Member] Courtyard at Hickory Hollow [Member]	Sep. 30, 2011 Fair Value, Measurements, Nonrecurring [Member] Outparcel Sale [Member]	Dec. 31, 2013 Fair Value, Measurements, Nonrecurring [Member] Outparcel Sale [Member]	Sep. 30, 2011 Fair Value, Measurements, Nonrecurring [Member] Columbia Place [Member]	Dec. 31, 2012 Minimum [Member]	Dec. 31, 2012 Maximum [Member]	Dec. 31, 2012 Imperial Valley Mall [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate		20.00%
Fair value assumptions, expected holding period	10 years
Assumed capitalization rate used to determine fair value																									10.00%	12.00%
Fair value assumptions, estimated cost of sale	1.00%
Long-lived assets fair value disclosure									$ 5,330	$ 25,645							$ 8,173		$ 31,900
Loss on impairment				(1,799)	47,212	47,212						20,453					67,665	23,315				(621)	(1,064)	50,683
Number of properties written down	2	2
Joint venture, ownership percentage																											60.00%
Property Carrying Values [Roll Forward]
Long-lived assets, beginning carrying value						57,231		25,403			5,754		45,178		102,409	31,157
Capital expenditures						5		264			644		262		267	908
Depreciation expense						(2,024)		(22)			(124)		(1,380)		(3,404)	(146)
Loss on impairment of real estate						(47,212)		(20,315)			(3,000)		(20,453)		(67,665)	(23,315)				2,843	5,843
Long-lived assets, ending carrying value					8,000	8,000		5,330			3,274		23,607		31,607	8,604
Concentration risk, percent of total revenue						0.70%					0.03%		0.60%
Non-cash impairment of long-lived asset				585
Net proceeds from sale of real estate	220,425	67,594	35,125	4,292																		1,477	1,186
Real estate investment property, net				$ 6,091	$ 8,000	$ 8,000	$ 55,212					$ 23,900		$ 44,353								$ 2,098	$ 2,250	$ 6,063