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           FAIR VALUE OF FINANCIAL INSTRUMENTS - Net Assets of Linked Transactions (Details 11) (USD $) 
        In Thousands, unless otherwise specified  | 
        
           Dec. 31, 2013 
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           Dec. 31, 2012 
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|---|---|---|---|---|---|---|---|---|---|---|
| Real estate securities, available-for-sale | $ 984,263 | [1] | $ 1,691,575 | [1] | ||||||
| Repurchase agreements | (556,347) | (929,435) | ||||||||
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           Linked Transactions 
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| Real estate securities, available-for-sale | 104,308 | [2] | [2] | |||||||
| Repurchase agreements | (60,646) | [3] | [3] | |||||||
| Net Assets recognized as linked transactions | $ 43,662 | |||||||||
          
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- Definition 
          The net asset value of assets and liabilities identified as linked transactions. No definition available. 
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- Definition 
          Amount of debt securities categorized neither as held-to-maturity nor trading. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security resale agreement between the entity and another party for the purchase and resale of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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