Pensions and Other Postretirement Plans (Accumulated Other Comprehensive Income) (Details 7) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Net amount	$ (649,185)	$ (388,591)
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial gain	(865,994)	(524,709)
Unrecognized prior service cost (credit)	(11,233)	1,676
Gross amount	(877,227)	(523,033)
Deferred tax liability (asset)	236,107	145,430
Net amount	(641,120)	(377,603)
Supplemental Executive Retirement Plan (SERP) [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial gain	(1,602)	(2,511)
Unrecognized prior service cost (credit)	0	0
Gross amount	(1,602)	(2,511)
Deferred tax liability (asset)	(2)	230
Net amount	(1,604)	(2,281)
Other Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial gain	(8,988)	(12,004)
Unrecognized prior service cost (credit)	0	(5)
Gross amount	(8,988)	(12,009)
Deferred tax liability (asset)	2,527	3,302
Net amount	$ (6,461)	$ (8,707)