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Merger Agreement (Details) $ in Thousands | Jul. 31, 2017 shares | Sep. 30, 2017 USD ($) branch | Dec. 31, 2016 USD ($)
--- | --- | --- | ---
Business Acquisition [Line Items] |  |  |
Amount of acquiree's assets |  | $ 2,155,901 | $ 2,023,493
Amount of acquiree's deposit liabilities |  | $ 1,890,970 | $ 1,772,700
Bank of Napa, N.A. (Napa) |  |  |
Business Acquisition [Line Items] |  |  |
Number of acquiree's branches | branch |  | 2 |
Amount of acquiree's assets |  | $ 255,300 |
Amount of acquiree's deposit liabilities |  | 226,100 |
Amount of acquiree's loan assets |  | $ 140,500 |
Bank of Napa, N.A. (Napa) |  |  |
Business Acquisition [Line Items] |  |  |
Shares received by Napa shareholders in merger per acquiree share | shares | 0.307 |  |

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