Benefit Plans (Schedule Of Benefit Plans) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Pension Costs
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 622	$ 575
Interest cost	1,033	1,316
Expected return on plan assets	(1,284)	(1,338)
Net cost	371	553
Postretirement Costs
Defined Benefit Plan Disclosure [Line Items]
Interest cost	191	242
Net cost	$ 191	$ 242