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Basis of Accounting and Consolidation - Additional Information (Details) - USD ($) |  | 3 Months Ended |
--- | --- | --- | ---
Mar. 20, 2023 | Mar. 31, 2024 | Mar. 31, 2023 | Dec. 31, 2023
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Common stock, par value (in dollars per share) |  | $ 4 |  | $ 4
Stock plans, term |  | 10 years |  |
Maximum number of shares to be issued in stock incentive plan (in shares) |  | 399,983 |  |
Employee discount for employee stock purchase plan |  | 15.00% |  |
Employee stock purchase plan, number of shares authorized |  | 600,000 |  |
Stock issued during period, shares, employee stock purchase plans |  | 8,612 | 7,963 |
Captive maximum gross premiums |  | $ 2,800,000 |  |
Employee Stock Option |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Common stock awarded in SI plan (in shares) |  | 0 |  |
Restricted Stock |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Common stock awarded in SI plan (in shares) |  | 53,766 | 60,550 |
Restricted Stock Units (RSUs) |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Common stock awarded in SI plan (in shares) |  | 39,150 | 37,900 |
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) | $ 0.01 |  |  |
Conversion of common stock | 1.15 |  |  |
Share Price | $ 4 |  |  |
Consideration payable in cash | $ 1,928 |  |  |
Consideration payable in shares | 3,290,222 |  |  |
Common stock consideration value | $ 93,508,000 |  |  |

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