Retirement Plans, Schedule of Change in Benefit Obligation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	$ 339,509	$ 495,272
Service cost	3,695	6,538	$ 7,961
Interest cost	18,356	14,779	14,239
Actuarial (gain) loss	13,241	(158,816)
Gross benefits paid	(32,052)	(12,665)
Settlements	0	(5,599)
Benefit obligation at end of year	342,749	339,509	495,272
Accumulated benefit obligation at end of year	326,987	325,274
SERP [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	833	1,033
Service cost	0	0	0
Interest cost	43	29	31
Actuarial (gain) loss	91	(74)
Gross benefits paid	(153)	(155)
Settlements	0	0
Benefit obligation at end of year	814	833	1,033
Accumulated benefit obligation at end of year	814	833
Other Postretirement Benefits [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	432	582
Service cost	0	0
Interest cost	22	17	17
Actuarial (gain) loss	65	(58)
Gross benefits paid	(104)	(109)
Settlements	0	0
Benefit obligation at end of year	415	432	$ 582
Accumulated benefit obligation at end of year	$ 415	$ 432