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Arrangements with Navient Corporation (Details) - USD ($) | 3 Months Ended |
--- | --- | ---
Mar. 31, 2016 | Mar. 31, 2015 | Dec. 31, 2015
Related Party Transaction [Line Items] |  |  |
Minimum days past due that company may required spin-off company to purchase loans | 90 days |  |
Period of hardship forbearance | 6 months |  |
Split loans, net | $ 12,021,022,000 |  | $ 10,515,505,000
Interest income from related party | 100,000 | $ 200,000 |
Gains on loans to related party | 0 | 0 |
Write-down to fair value for loans sold to related party | 2,100,000 | 2,200,000 |
Split Loans |  |  |
Related Party Transaction [Line Items] |  |  |
Split loans, net | 82,000,000 |  |
Participated loans |  |  |
Related Party Transaction [Line Items] |  |  |
Loans sold to related party | $ 5,500,000 | $ 8,700,000 |

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