Retirement Plans, Summary of Change in Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Pension Plan [Member]
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	$ 341,061	$ 430,821
Actual return on plan assets	58,734	(72,402)
Employer contribution	8,174	906
Gross benefits paid	(32,052)	(12,665)
Settlements	0	(5,599)
Fair value of plan assets at end of year	375,917	341,061
SERP [Member]
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contribution	153	155
Gross benefits paid	(153)	(155)
Settlements	0	0
Fair value of plan assets at end of year	0	0
Other Postretirement Benefits [Member]
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contribution	104	109
Gross benefits paid	(104)	(109)
Settlements	0	0
Fair value of plan assets at end of year	$ 0	$ 0