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Commitments and Contingencies Narrative (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2017 | Sep. 30, 2016 | Sep. 30, 2017 | Sep. 30, 2016 | Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract] |  |  |  |  |
SBA Loans, Probability of Future Losses | $ 2,700 |  | $ 2,700 |  |
SBA Recourse Provision | $ 1,315 | $ 375 | $ 2,095 | $ 449 | $ 2,068

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