Benefit Plans (Schedule Of Plan's Funded Status) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Benefit Plans [Abstract]
Benefit obligation at beginning of measurement year	$ 17,881	$ 18,609	$ 19,679
Service cost	317	337	377
Interest cost	667	701	695
Actuarial loss	2,260	632	(906)
Settlement loss		(1,590)
Benefits paid	(1,236)	(808)	(1,236)
Benefit obligation at end of measurement year	19,889	17,881	18,609
Fair value of plan assets at beginning of measurement year	17,062	18,301	19,677
Actual return on plan assets net of expenses	1,366	1,159	(140)
Settlement loss		(1,590)
Benefits paid	(1,236)	(808)	(1,236)
Fair value of plan assets at end of measurement year	17,192	17,062	18,301
Defined Benefit Plan, Funded Status of Plan, Total	$ (2,697)	$ (819)	$ (308)