Benefit Plans (Schedule Of Benefit Plans) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Pension Costs
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 496	$ 508
Interest cost	1,385	1,498
Expected return on plan assets	(1,389)	(1,310)
Net cost	492	696
Postretirement Costs
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1
Interest cost	241	272
Net cost	$ 242	$ 273