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Commitments and Contingencies (Details) | Apr. 25, 2018 USD ($) $ / shares | Jun. 30, 2018 USD ($) | Dec. 31, 2017 USD ($) | May 30, 2017 $ / shares
--- | --- | --- | --- | ---
Loss Contingencies [Line Items] |  |  |  |
Notional amount of terminated commitment |  | $ 492,100,000 | $ 433,000,000 |
Price per share (in dollars per share) | $ / shares |  |  |  | $ 34.30
Mortgage Loans Held for Sale |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Mortgage loans with recourse provision in effect |  | 600,000 |  |
Construction Contracts |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Commitments under construction contracts |  | $ 3,500,000 |  |
INB |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Business Acquisition, Date of Acquisition Agreement | Apr. 25, 2018 |  |  |
Number of banking offices acquired | 20 |  |  |
INB |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Number of banking offices acquired | 20 |  |  |
Estimate of Payments to Acquire Businesses, Gross | $ 159.7 |  |  |
Estimate value per share of Acquisition | $ / shares | $ 20.69 |  |  |

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