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Basis of Accounting and Consolidation - Additional Information (Details) - USD ($)			3 Months Ended		6 Months Ended
	Mar. 21, 2023	Feb. 14, 2022	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Summary Of Significant Accounting Policies [Line Items]
Common stock, par value (in dollars per share)			$ 4		$ 4		$ 4
Deposits			$ 5,219,585,000		$ 5,219,585,000		$ 5,257,001,000
Stock plans, term					10 years
Maximum number of shares to be issued in stock incentive plan (in shares)			399,983		399,983
Employee discount for employee stock purchase plan					15.00%
Employee stock purchase plan, number of shares authorized			600,000		600,000
Stock issued during period, shares, employee stock purchase plans			9,175	5,177	17,138	8,326
Captive maximum gross premiums					$ 2,650,000
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)					59,950	61,400
Restricted Stock Units (RSUs)
Summary Of Significant Accounting Policies [Line Items]
Common stock awarded in SI plan (in shares)					37,900	37,150
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 shares	3,330,176
Delta Bancshares Company
Summary Of Significant Accounting Policies [Line Items]
Percentage of issued and outstanding shares acquired		100.00%
Common stock, par value (in dollars per share)		$ 10.00
Share Price		$ 4.00
Consideration payable in cash		$ 15,150,000
Consideration payable in shares		2,292,270

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