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Marketable Securities (Details) - USD ($) $ / shares in Units, $ in Thousands | Sep. 30, 2015 | Dec. 31, 2014
--- | --- | ---
Investment Holdings [Line Items] |  |
Fair Value | $ 41,119 | $ 44,646
Macerich interest [Member] |  |
Investment Holdings [Line Items] |  |
Macerich Common Shares | 535,265 | 535,265
Economic basis per share (in dollars per share) | $ 56.05 |
GAAP Cost | $ 30,000 |
Fair Value | $ 41,119 | $ 44,646
Closing share price (in dollars per share) | $ 76.82 | $ 83.41

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