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Net Loss on Early Extinguishment of Debt (Details) (USD $) In Thousands, unless otherwise specified | 12 Months Ended | 3 Months Ended
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Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2009 | Mar. 31, 2010 Kings Plaza Regional Shopping Center [Member]
Extinguishment of Debt Disclosure [Line Items] |  |  |  |
Early Extinguishment of Debt |  |  |  | $ 27,500
Extinguishment Of Debt Fair Value Of Payments Made |  |  |  | 28,738
Net loss on early extinguishment of debt | $ 0 | $ 1,238 | $ 519 | $ 1,238

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