Pension Plans And Other Postretirement Benefits (Components Of Net Periodic Benefit Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 775	$ 992	$ 2,728	$ 2,783
Interest cost	3,351	3,642	9,667	10,003
Expected return on plan assets	(5,733)	(5,676)	(17,432)	(15,573)
Amortization of prior service cost (credit)	140	148	419	444
Amortization of actuarial loss	555	1,992	2,352	5,976
Net periodic benefit cost	(912)	1,098	(2,266)	3,633
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	698	662	2,094	1,614
Interest cost	840	989	2,520	2,707
Expected return on plan assets	(1,039)	(1,111)	(3,117)	(2,969)
Amortization of prior service cost (credit)	(108)	(116)	(324)	(348)
Amortization of actuarial loss	55	156	165	468
Net periodic benefit cost	$ 446	$ 580	$ 1,338	$ 1,472