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Summary of Significant Accounting Policies - Dividend (Details) | Nov. 06, 2017 USD ($) | Oct. 17, 2017 $ / shares | Sep. 30, 2017 USD ($)
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Summary of Significant Accounting Policies |  |  |
Decrease in future quarterly net interest income (in basis points) |  |  | 10.0
Debt Instrument, Unamortized Premium |  |  | $ 25,000,000
Dividends Payable, Amount Per Share | $ / shares |  | $ 0.01 |
Payments of Dividends | $ 296,000 |  |

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