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, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Pension Benefits
Plan expense for noncontributory benefit pension plan and post-retirement health and life plans
Interest cost	$ 227	$ 248	$ 454	$ 497
Expected return on plan assets	(248)	(309)	(496)	(618)
Recognized actuarial loss (gain)	129	131	258	262
Net periodic benefit cost (return)	108	70	216	141
Other Benefits
Plan expense for noncontributory benefit pension plan and post-retirement health and life plans
Interest cost	6	5	11	11
Expected return on plan assets	0	0	0	0
Recognized actuarial loss (gain)	(24)	(16)	(47)	(31)
Net periodic benefit cost (return)	$ (18)	$ (11)	$ (36)	$ (20)