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           REAL ESTATE RELATED LOANS, RESIDENTIAL MORTGAGE LOANS AND SUBPRIME MORTGAGE LOANS - Subprime Characteristics (Details 9) (USD $) 
        In Thousands, unless otherwise specified  | 
        12 Months Ended | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 
           Dec. 31, 2013 
         | 
        
           Dec. 31, 2012 
         | 
      ||||||||||||||
| Loan unpaid principal balance (UPB) | $ 879,281 | [1] | |||||||||||||
| Weighted Average Coupon | 3.65% | 3.04% | |||||||||||||
| Debt Face Amount | 3,030,490 | 2,786,059 | |||||||||||||
| 
           Subprime Portfolio I 
         | 
        |||||||||||||||
| Loan unpaid principal balance (UPB) | 372,661 | [1] | |||||||||||||
| Weighted Average Coupon | 5.88% | ||||||||||||||
| Delinquencies of 60 or more days (UPB) | 110,539 | [2] | |||||||||||||
| Net credit losses | 26,388 | 27,548 | |||||||||||||
| Cumulative net credit losses | 246,805 | ||||||||||||||
| Cumulative net credit losses as a % of original UPB | 16.40% | ||||||||||||||
| Percentage of ARM loans | 51.50% | [3] | |||||||||||||
| Percentage of loans with original loan-to-value ratio >90% | 9.40% | ||||||||||||||
| Percentage of interest-only loans | 11.40% | ||||||||||||||
| Debt Face Amount | 368,661 | [4],[5] | |||||||||||||
| Weighted average funding cost of debt | 0.53% | [6] | |||||||||||||
| 
           Subprime Portfolio II 
         | 
        |||||||||||||||
| Loan unpaid principal balance (UPB) | 506,620 | [1] | |||||||||||||
| Weighted Average Coupon | 5.19% | ||||||||||||||
| Delinquencies of 60 or more days (UPB) | 204,653 | [2] | |||||||||||||
| Net credit losses | 44,855 | 34,866 | |||||||||||||
| Cumulative net credit losses | 301,574 | ||||||||||||||
| Cumulative net credit losses as a % of original UPB | 27.70% | ||||||||||||||
| Percentage of ARM loans | 57.00% | [3] | |||||||||||||
| Percentage of loans with original loan-to-value ratio >90% | 7.70% | ||||||||||||||
| Percentage of interest-only loans | 14.20% | ||||||||||||||
| Debt Face Amount | $ 506,620 | [4],[5] | |||||||||||||
| Weighted average funding cost of debt | 0.45% | [6] | |||||||||||||
          
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- Definition 
          Weighted average of all coupon rates for each asset type. No definition available. 
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- Definition 
          Cumulative credit losses on subprime securitized mortgage loans. No definition available. 
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- Definition 
          The percentage of cumulative credit losses to the original loan unpaid principal balance on subprime securitized mortgage loans. No definition available. 
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- Definition 
          Percentage of securitized subprime loans that are adjustable-rate mortgage loans (ARM loans). No definition available. 
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- Definition 
          Percentage of securitized subprime loans that are interest-only loans. No definition available. 
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- Definition 
          Percentage of securitized subprime loans with an original loan to value ratio greater than 90%.. No definition available. 
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- Definition 
          Weighted average of all funding costs for all securitized subprime mortgage loans. No definition available. 
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- Definition 
          Face (par) amount of debt instrument at time of issuance. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          This is the principal amount of loans (across all types of loans) that are overdue in payment by a set number of days. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of credit loss after recoveries for transferred financial assets that continue to be recognized in the statement of financial position. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          This is the sum of principal amount outstanding for both securitized and unsecuritized loans of all types. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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