Employee Benefit and Deferred Compensation Plans - Plan Expense for Non-Contributory Benefit Pension Plan and Post-Retirement Health and Life Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Pension Benefits
Plan expense for noncontributory benefit pension plan and post-retirement health and life plans
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	248	185	497	369
Expected return on plan assets	(309)	(421)	(618)	(842)
Recognized actuarial loss (gain)	131	61	262	122
Net periodic benefit cost (return)	70	(175)	141	(351)
Other Benefits
Plan expense for noncontributory benefit pension plan and post-retirement health and life plans
Service cost	0	1	0	2
Interest cost	5	3	11	6
Expected return on plan assets	0	0	0	0
Recognized actuarial loss (gain)	(16)	(19)	(31)	(38)
Net periodic benefit cost (return)	$ (11)	$ (15)	$ (20)	$ (30)