Discontinued Operations and Disposition of Real Estate and Real Estate Investments (Details) (USD $)	12 Months Ended
	Dec. 31, 2011 Property	Dec. 31, 2010 Property	Dec. 31, 2009 Property
Balance sheet relating to asset held for sale
Land	$ 1,089,000
Building	1,178,000
Fixtures and tenant improvements	1,000,000
Carrying amount of real estate assets held for sale	3,267,000
Less: Accumulated depreciation	(977,000)
Total assets held for sale	2,290,000	0
Operating results relating to assets sold or designated as held for sale
Revenues	27,798,000	52,027,000	87,323,000
Expenses:
Operating expenses	10,174,000	22,112,000	39,785,000
Impairment charge	24,000,000	87,100,000	142,000,000
Interest, net	7,500,000	20,989,000	33,266,000
Debt extinguishment costs, net	7,191,000	409,000	439,000
Depreciation and amortization	7,677,000	17,457,000	29,744,000
Total expenses	56,571,000	148,012,000	245,207,000
Loss from discontinued operations	(28,773,000)	(95,985,000)	(157,884,000)
Gain on deconsolidation of interests	4,716,000	5,221,000
Gain (loss) on disposition of real estate, net of tax	40,163,000	5,775,000	(24,027,000)
Net gain (loss)	16,106,000	(84,989,000)	(181,911,000)
Net gains on disposition of real estate and real estate investments
Land sales	(400,000)	1,000,000	4,800,000
Previously deferred gains and other gains and losses on dispositions	7,500,000	300,000	4,300,000
Net gains on disposition of real estate and real estate investments	$ 7,079,000	$ 1,318,000	$ 9,127,000
Discontinued Operations and Disposition of Real Estate and Real Estate Investments (Textual) [Abstract]
Number of properties sold	34	34	34
Number of assets held for sale	1
Number of properties included in discontinued operations	97
Number of disposed properties previously included in shopping center segment	96
Number of disposed properties previously included in other investments segment	1
Other properties deconsolidated for accounting purpose	26	26	26