Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Pension and Supplemental Executive Retirement Plans
Components of Net Periodic Benefit Cost [Abstract]
Company service cost	$ 0	$ 1,813	$ 0	$ 5,439
Interest cost	3,297	2,863	10,278	8,588
Expected return on plan assets	(3,426)	(4,907)	(10,432)	(14,723)
Net actuarial losses (gains)	529	1,266	1,656	3,798
Prior service cost (credit)	87	(57)	259	(163)
Cost of settlements and curtailments	334	5,671	9,181	5,671
Net periodic benefit cost (benefit)	821	6,649	10,942	8,610
Other Postretirement Benefit Plans
Components of Net Periodic Benefit Cost [Abstract]
Company service cost	374	327	1,122	981
Interest cost	409	173	1,225	521
Expected return on plan assets	(2,059)	(2,625)	(6,176)	(7,876)
Net actuarial losses (gains)	(38)	(776)	(113)	(2,328)
Prior service cost (credit)	465	123	1,396	367
Cost of settlements and curtailments	0	0	0	0
Net periodic benefit cost (benefit)	$ (849)	$ (2,778)	$ (2,546)	$ (8,335)