Pensions and Other Postretirement Plans (Accumulated Other Comprehensive Income) (Details 7) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Net amount	$ (325,921)	$ (232,836)
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial (gain) loss	(467,535)	(313,809)
Unrecognized prior service cost	10,116	7,273
Gross amount	(457,419)	(306,536)
Deferred tax liability (asset)	123,503	82,765
Net amount	(333,916)	(223,771)
Supplemental Executive Retirement Plan (SERP) [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial (gain) loss	30,500	17,270
Unrecognized prior service cost	698	1,037
Gross amount	31,198	18,307
Deferred tax liability (asset)	(8,423)	(4,943)
Net amount	22,775	13,364
Other Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial (gain) loss	(19,747)	(22,861)
Unrecognized prior service cost	(500)	(7,863)
Gross amount	(20,247)	(30,724)
Deferred tax liability (asset)	5,467	8,295
Net amount	$ (14,780)	$ (22,429)