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Summary of Significant Accounting Policies - Dividend (Details) - USD ($) | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Jan. 17, 2017 | Dec. 31, 2015 | Dec. 31, 2014
90-Days or Greater Past Due Loans |  |  |  |  |
Period from due date after which accrual of interest income is discontinued | 90 days |  |  |  |
Accumulated other comprehensive income (loss) breakdown |  |  |  |  |
Unrealized gains on securities | $ 2,200,000 |  |  |  |
Unrealized losses on securities |  | $ 8,200,000 |  |  |
Unrealized Loss on Price Risk Cash Flow Derivatives, before Tax | 760,000 | 596,000 |  |  |
Allowance for Loan Losses |  |  |  |  |
Loans and Leases Receivable, Allowance | 17,461,000 | 16,158,000 |  | $ 16,223,000 | $ 21,637,000
Dividends Payable, Amount Per Share |  |  | $ 0.01 |  |
All other |  |  |  |  |
Allowance for Loan Losses |  |  |  |  |
Loans and Leases Receivable, Allowance | $ 542,000 | $ 435,000 |  | $ 1,965,000 | $ 2,506,000

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