| 
           FAIR VALUE OF FINANCIAL INSTRUMENTS - Recurring Basis (Details 2) (USD $) 
        In Thousands, unless otherwise specified  | 
        
           Dec. 31, 2013 
         | 
        
           Dec. 31, 2012 
         | 
      ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | $ 984,263 | [1] | $ 1,691,575 | [1] | ||||||||||
| Derivative assets: | ||||||||||||||
| Derivative assets | 43,662 | 165 | ||||||||||||
| 
           Principal Balance 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 1,170,905 | [2] | ||||||||||||
| Derivative assets: | ||||||||||||||
| Derivative assets | 116,806 | [2],[3],[4] | ||||||||||||
| Derivative Liabilities: | ||||||||||||||
| Interest rate swaps, treated as hedges | 105,031 | [2],[4],[5] | ||||||||||||
| Interest rate swaps, not treated as hedges | 185,871 | [2],[3],[4] | ||||||||||||
| 
           Carrying Amount 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 984,263 | [2] | 1,691,575 | [2] | ||||||||||
| Derivative assets: | ||||||||||||||
| Derivative assets | 43,662 | [2],[3],[4] | 165 | [2],[3],[4] | ||||||||||
| Derivative Liabilities: | ||||||||||||||
| Interest rate swaps, treated as hedges | 6,203 | [2],[4],[5] | 12,175 | [2],[4],[5] | ||||||||||
| Interest rate swaps, not treated as hedges | 7,592 | [2],[3],[4] | 19,401 | [2],[3],[4] | ||||||||||
| 
           Estimated Fair Value 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 984,263 | [2] | 1,691,575 | [2] | ||||||||||
| Derivative assets: | ||||||||||||||
| Derivative assets | 43,662 | [2],[3],[4] | 165 | [2],[3],[4] | ||||||||||
| Derivative Liabilities: | ||||||||||||||
| Interest rate swaps, treated as hedges | 6,203 | [2],[4],[5] | 12,175 | [2],[4],[5] | ||||||||||
| Interest rate swaps, not treated as hedges | 7,592 | [2],[3],[4] | 19,401 | [2],[3],[4] | ||||||||||
| 
           Measured on a Recurring Basis | Level 2 Inputs 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 582,456 | |||||||||||||
| Derivative assets: | ||||||||||||||
| Linked transactions at fair value | ||||||||||||||
| Derivative assets | ||||||||||||||
| Derivative Liabilities: | ||||||||||||||
| Interest rate swaps, treated as hedges | 6,203 | |||||||||||||
| Interest rate swaps, not treated as hedges | 7,592 | |||||||||||||
| Derivative liabilities | 13,795 | |||||||||||||
| 
           Measured on a Recurring Basis | Level 2 Inputs | CMBS 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | ||||||||||||||
| 
           Measured on a Recurring Basis | Level 2 Inputs | REIT Debt 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 31,186 | |||||||||||||
| 
           Measured on a Recurring Basis | Level 2 Inputs | Non-Agency RMBS 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | ||||||||||||||
| 
           Measured on a Recurring Basis | Level 2 Inputs | ABS Franchise 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | ||||||||||||||
| 
           Measured on a Recurring Basis | Level 2 Inputs | FNMA/FHLMC Securities 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 551,270 | |||||||||||||
| 
           Measured on a Recurring Basis | Level 2 Inputs | CDOs 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | ||||||||||||||
| 
           Measured on a Recurring Basis | Level 3 Inputs 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 401,807 | |||||||||||||
| Derivative assets: | ||||||||||||||
| Linked transactions at fair value | 43,662 | |||||||||||||
| Derivative assets | 43,662 | |||||||||||||
| Derivative Liabilities: | ||||||||||||||
| Interest rate swaps, treated as hedges | ||||||||||||||
| Interest rate swaps, not treated as hedges | ||||||||||||||
| Derivative liabilities | ||||||||||||||
| 
           Measured on a Recurring Basis | Level 3 Inputs | CMBS 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 284,469 | |||||||||||||
| 
           Measured on a Recurring Basis | Level 3 Inputs | REIT Debt 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | ||||||||||||||
| 
           Measured on a Recurring Basis | Level 3 Inputs | Non-Agency RMBS 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 57,581 | |||||||||||||
| 
           Measured on a Recurring Basis | Level 3 Inputs | ABS Franchise 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | ||||||||||||||
| 
           Measured on a Recurring Basis | Level 3 Inputs | FNMA/FHLMC Securities 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | ||||||||||||||
| 
           Measured on a Recurring Basis | Level 3 Inputs | CDOs 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 59,757 | |||||||||||||
| 
           Measured on a Recurring Basis | Principal Balance 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 1,170,905 | |||||||||||||
| Derivative assets: | ||||||||||||||
| Linked transactions at fair value | 116,806 | |||||||||||||
| Derivative assets | 116,806 | |||||||||||||
| Derivative Liabilities: | ||||||||||||||
| Interest rate swaps, treated as hedges | 105,031 | |||||||||||||
| Interest rate swaps, not treated as hedges | 185,871 | |||||||||||||
| Derivative liabilities | 290,902 | |||||||||||||
| 
           Measured on a Recurring Basis | Principal Balance | CMBS 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 333,121 | |||||||||||||
| 
           Measured on a Recurring Basis | Principal Balance | REIT Debt 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 29,200 | |||||||||||||
| 
           Measured on a Recurring Basis | Principal Balance | Non-Agency RMBS 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 96,762 | |||||||||||||
| 
           Measured on a Recurring Basis | Principal Balance | ABS Franchise 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 8,464 | |||||||||||||
| 
           Measured on a Recurring Basis | Principal Balance | FNMA/FHLMC Securities 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 514,994 | |||||||||||||
| 
           Measured on a Recurring Basis | Principal Balance | CDOs 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 188,364 | |||||||||||||
| 
           Measured on a Recurring Basis | Carrying Amount 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 984,263 | |||||||||||||
| Derivative assets: | ||||||||||||||
| Linked transactions at fair value | 43,662 | |||||||||||||
| Derivative assets | 43,662 | |||||||||||||
| Derivative Liabilities: | ||||||||||||||
| Interest rate swaps, treated as hedges | 6,203 | |||||||||||||
| Interest rate swaps, not treated as hedges | 7,592 | |||||||||||||
| Derivative liabilities | 13,795 | |||||||||||||
| 
           Measured on a Recurring Basis | Carrying Amount | CMBS 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 284,469 | |||||||||||||
| 
           Measured on a Recurring Basis | Carrying Amount | REIT Debt 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 31,186 | |||||||||||||
| 
           Measured on a Recurring Basis | Carrying Amount | Non-Agency RMBS 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 57,581 | |||||||||||||
| 
           Measured on a Recurring Basis | Carrying Amount | ABS Franchise 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | ||||||||||||||
| 
           Measured on a Recurring Basis | Carrying Amount | FNMA/FHLMC Securities 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 551,270 | |||||||||||||
| 
           Measured on a Recurring Basis | Carrying Amount | CDOs 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 59,757 | |||||||||||||
| 
           Measured on a Recurring Basis | Estimated Fair Value 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 984,263 | |||||||||||||
| Derivative assets: | ||||||||||||||
| Linked transactions at fair value | 43,662 | |||||||||||||
| Derivative assets | 43,662 | |||||||||||||
| Derivative Liabilities: | ||||||||||||||
| Interest rate swaps, treated as hedges | 6,203 | |||||||||||||
| Interest rate swaps, not treated as hedges | 7,592 | |||||||||||||
| Derivative liabilities | 13,795 | |||||||||||||
| 
           Measured on a Recurring Basis | Estimated Fair Value | CMBS 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 284,469 | |||||||||||||
| 
           Measured on a Recurring Basis | Estimated Fair Value | REIT Debt 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 31,186 | |||||||||||||
| 
           Measured on a Recurring Basis | Estimated Fair Value | Non-Agency RMBS 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 57,581 | |||||||||||||
| 
           Measured on a Recurring Basis | Estimated Fair Value | ABS Franchise 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | ||||||||||||||
| 
           Measured on a Recurring Basis | Estimated Fair Value | FNMA/FHLMC Securities 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | 551,270 | |||||||||||||
| 
           Measured on a Recurring Basis | Estimated Fair Value | CDOs 
         | 
        ||||||||||||||
| Assets: | ||||||||||||||
| Real estate securities, available-for-sale | $ 59,757 | |||||||||||||
          
  | 
      ||||||||||||||