Retirement Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
RAP
Retirements Plans [Line Items]
Defined Benefit Plan, Description	The Corporation has a noncontributory defined benefit RAP, covering substantially all employees who meet participation requirements. The benefits are based primarily on years of service and the employee’s compensation paid. Employees of acquired entities generally participate in the RAP after consummation of the business combinations. Any retirement plans of acquired entities are typically merged into the RAP after completion of the mergers, and credit is usually given to employees for years of service at the acquired institution for vesting and eligibility purposes.
Actual return on plan assets percentage	15.80%	(15.03%)
Employer contributions	$ 0	$ 0
Interest crediting rate	3.77%	3.46%
Postretirement Plan
Retirements Plans [Line Items]
Defined Benefit Plan, Description	The Corporation also provides legacy healthcare access to a limited group of retired employees from a previous acquisition in the Postretirement Plan. There are no other active retiree healthcare plans.
Employer contributions	$ 171	$ 193
Defined Benefit Plan, Health Care Cost Trend, Reduction in Trend Rate Minimum	4.00%
Ultimate future rate	5.00%
401(k) plan
Retirements Plans [Line Items]
Total expense related to 401(k)	$ 16,000	$ 15,000	$ 13,000
Minimum [Member] | RAP | Equity securities
Retirements Plans [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	50.00%
Minimum [Member] | RAP | Fixed-income securities
Retirements Plans [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	30.00%
Minimum [Member] | RAP | Other Cash Equivalents
Retirements Plans [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	0.00%
Minimum [Member] | RAP | Alternative securities
Retirements Plans [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	0.00%
Maximum [Member] | RAP | Equity securities
Retirements Plans [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	70.00%
Maximum [Member] | RAP | Fixed-income securities
Retirements Plans [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	50.00%
Maximum [Member] | RAP | Other Cash Equivalents
Retirements Plans [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	10.00%
Maximum [Member] | RAP | Alternative securities
Retirements Plans [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	15.00%