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Junior Subordinated Debt/Trust Preferred Securities (Details)		1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Sep. 30, 2009 USD ($)	Sep. 30, 2015 USD ($)	Aug. 31, 2015 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) quarter	Jun. 30, 2016 USD ($)	Dec. 31, 2016
Debt Instrument [Line Items]
Gain (loss) on fair value option of financial liability				$ (264,000)	$ 113,000	$ (601,000)	$ 471,000
Adjustment related to fair value calculations net of tax				(126,000)	$ 66,000	(354,000)	$ 277,000
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 rate			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				$ 3,096,000		$ 3,096,000
Junior Subordinated Debt | Significant unobservable inputs level 3 | Discounted cash flow valuation technique
Debt Instrument [Line Items]
Adjustment for difference between comparable sales						5.86%		6.46%
Junior Subordinated Debt | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate						1.29%
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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Adjustment to the amount at which a liability incurred or settled in a current transaction between willing parties, that is, other than in a forced or liquidation sale, net of tax.

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The net gain (loss) resulting from the change in the fair value estimate of liabilities elected to be measured under the adoption of FAS 159.

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The terms of the debentures and trust indentures allow for the entity to defer interest payments for a number of maximum consecutive quarters without default or penalty.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Face (par) amount of debt instrument at time of issuance.

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Gross amount of debt extinguished.

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Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

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