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Marketable Securities (Details) (USD $) | 12 Months Ended
--- | ---
Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2010
Marketable Securities [Abstract] |  |  |
Marketable securities received in connection with the sale of real estate | $ 30,000,000 | $ 0 | $ 0
Macerich Interest [Member] |  |  |
Marketable Securities [Abstract] |  |  |
Fair Value | 31,206,000 |  |
GAAP Cost | 30,000,000 |  |
Unrealized Gain | $ 1,206,000 |  |
Economic basis per share | $ 56.05 |  |
Closing share price | $ 58.30 |  |
Percentage of outstanding common shares owned | 0.39% |  |
Macerich common shares | 535,265 |  |

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