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Basis of Accounting and Consolidation - Additional Information (Details) |  | 3 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Mar. 20, 2023 USD ($) $ / shares shares | Sep. 30, 2024 USD ($) | Jun. 30, 2024 USD ($) | Dec. 31, 2024 USD ($) Segment $ / shares shares | Dec. 31, 2023 USD ($) $ / shares shares | Dec. 31, 2022 USD ($) shares | Dec. 31, 2021 USD ($)
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Common stock, par value (in dollars per share) | $ / shares |  |  |  | $ 4 | $ 4 |  |
Number of operating segment | Segment |  |  |  | 1 |  |  |
Assets |  |  |  | $ 7,519,734,000 | $ 7,586,794,000 |  |
Loans |  |  |  | 5,595,666,000 | 5,506,910,000 |  |
Deposits |  |  |  | $ 6,057,096,000 | 6,123,659,000 |  |
Federal funds selling period |  |  |  | 1 day |  |  |
Intangible assets amortization period |  |  |  | 15 years |  |  |
Captive maximum gross premiums |  |  |  | $ 2,800,000 |  |  |
Value of trust accounts |  |  |  | $ 6,400,000,000 | $ 6,100,000,000 |  |
Stock plans, term |  |  |  | 10 years |  |  |
Maximum number of shares to be issued in stock incentive plan (in shares) | shares |  |  |  | 550,000 |  |  |
RSA/RSU, grants in period, gross | shares |  |  |  | 80,332 | 45,986 | 63,150 |
Employee discount for employee stock purchase plan |  |  |  | 15.00% |  |  |
Employee stock purchase plan, number of shares authorized | shares |  |  |  | 600,000 |  |  |
Stock issued during period, shares, employee stock purchase plans | shares |  |  |  | 32,936 | 38,989 | 23,055 |
Right of use lease assets |  |  |  | $ 13,861,000 | $ 14,306,000 |  |
Lease liability |  |  |  | 14,190,000 | 14,615,000 |  |
Cumulative change in accounting principal |  |  |  | 846,391,000 | 793,204,000 | $ 633,155,000 | $ 633,894,000
Allowance for credit losses on loans |  |  |  | $ 70,182,000 | $ 68,675,000 | $ 59,093,000 | $ 54,655,000
Employee Stock Purchase Plan |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Shares available for issuance | shares |  |  |  | 473,336 |  |  |
Minimum |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Certificates of deposit investments original maturities period |  |  |  | 3 years |  |  |
Maximum |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Certificates of deposit investments original maturities period |  |  |  | 5 years |  |  |
Mid Rivers Insurance Group, Inc. |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Purchase price |  | $ 10,100,000 |  |  |  |  |
Purdum, Gray, Ingledue, Beck, Inc. |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Purchase price |  |  | $ 10,200,000 |  |  |  |
Blackhawk Bancorp, Inc |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |
Percentage of issued and outstanding shares acquired | 100.00% |  |  |  |  |  |
Common stock, par value (in dollars per share) | $ / shares | $ 0.01 |  |  |  |  |  |
Share Price | $ / shares | $ 4 |  |  |  |  |  |
Consideration payable in cash | $ 2,000 |  |  |  |  |  |
Consideration payable in shares | shares | 3,290,222 |  |  |  |  |  |
Conversion of common stock | shares | 1.15 |  |  |  |  |  |
Common stock consideration value | $ 93,508,000 |  |  |  |  |  |
Purchase price | $ 93,510,000 |  |  |  |  |  |

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