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Mergers and Acquisitions Pro Forma Summary (Details) - 2018 acquisitions - USD ($) $ in Thousands | 3 Months Ended
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Mar. 31, 2018 | Mar. 31, 2017
Pro Forma Information |  |
Net interest income and non-interest income | $ 130,068 | $ 120,646
Net income | $ 33,948 | $ 35,457

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