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Acquisition - Narrative (Details) - MBT $ in Thousands, shares in Millions |  | 12 Months Ended
--- | --- | ---
Sep. 01, 2019 USD ($) bank_branch shares | Dec. 31, 2019 USD ($)
Business Acquisition [Line Items] |  |
Percentage of interest acquired | 100.00% |
Number of banking centers acquired | bank_branch | 20 |
Stock issued as part of acquisition, value | $ 229,900 |
Core deposit intangible | 16,527 |
Operating revenue |  | $ 19,700
Non-recurring expenses |  | $ 19,700
Core deposit intangibles acquired |  |
Business Acquisition [Line Items] |  |
Core deposit intangible | $ 16,527 |
Acquired intangible asset, expected useful life | 10 years |
Common Stock |  |
Business Acquisition [Line Items] |  |
Number of shares of common stock | 0.275 |
Stock issued as a part of acquisition (in shares) | shares | 6.4 |

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