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Junior Subordinated Debt/Trust Preferred Securities (Details) |  | 1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | ---
Sep. 30, 2009 USD ($) | Aug. 31, 2015 USD ($) | Sep. 30, 2015 USD ($) | Sep. 30, 2014 USD ($) | Sep. 30, 2015 USD ($) quarter | Sep. 30, 2014 USD ($) | Dec. 31, 2014
Debt Instrument [Line Items] |  |  |  |  |  |  |
Gain on redemption of Jr subordinated debentures |  |  | $ 78,000 | $ 0 | $ 78,000 | $ 0 |
Gain (loss) on fair value option of financial liability |  |  | 148,000 | 95,000 | 346,000 | (34,000) |
Adjustment related to fair value calculations net of tax |  |  | 86,000 | $ 56,000 | 204,000 | $ 20,000 |
Junior Subordinated Debt |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt instrument, frequency of periodic payment | quarterly |  |  |  |  |  |
Amount of junior subordinated debentures relating to trust preferred securities | $ 15,000,000 |  | 12,000,000.0 |  | $ 12,000,000.0 |  |
Maximum number of consecutive quarters the entity defer interest payments without default or penalty | quarter |  |  |  |  | 20 |  |
Debt instrument, unamortized discount |  | 40.00% |  |  |  |  |
Debt instrument, repurchased face amount |  | $ 3,000,000 |  |  |  |  |
Gain on redemption of Jr subordinated debentures |  |  |  |  | $ 78,000 |  |
Life of debt instrument |  |  |  |  | 30 years |  |
Fair value measurement option, gain (loss) on long-term debt instruments |  |  | $ 4,632,000 |  | $ 4,632,000 |  |
Junior Subordinated Debt | Significant Unobservable Inputs Level 3 | Discounted Cash Flow Valuation Technique |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Discount rate used in the valuation of debt instrument (in hundredths) |  |  |  |  | 6.90% |  | 6.87%
Junior Subordinated Debt | London Interbank Offered Rate (LIBOR) |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Basis spread on variable rate |  |  |  |  | 129.00% |  |
Junior Subordinated Debt | United Security Bank |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Amount of junior subordinated debentures relating to trust preferred securities |  | $ 3,000,000.0 |  |  |  |  |

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