Retirement Plans, Summary of Funded Status at End of Year (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pension Plan [Member]
Funded status at end of year [Abstract]
Fair value of plan assets	$ 411,449	$ 375,917	$ 341,061
Benefit obligations	(321,210)	(342,749)	(339,509)
Funded status and amount recognized at end of year	90,239	33,168
SERP [Member]
Funded status at end of year [Abstract]
Fair value of plan assets	0	0	0
Benefit obligations	(752)	(814)	(833)
Funded status and amount recognized at end of year	(752)	(814)
Other Postretirement Benefits [Member]
Funded status at end of year [Abstract]
Fair value of plan assets	0	0	0
Benefit obligations	(396)	(415)	$ (432)
Funded status and amount recognized at end of year	$ (396)	$ (415)