Employee Benefits And Deferred Compensation Plans (Schedule Of Defined Benefit Plans Disclosures, SERP) (Details) - Supplemental Executive Retirement Plan [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Change in benefit obligation:
Benefit obligation at the beginning of the year	$ 4,255	$ 4,349
Service cost	168	188	$ 194
Interest cost	137	144	146
Actuarial (gain) loss	175	(234)
Benefits paid	(193)	(192)
Benefit obligation at the end of the year	4,542	4,255	4,349
Change in plan assets:
Fair value of plan assets at beginning of year
Actual return on plan assets
Employer contributions	193	192
Benefits paid	(193)	(192)
Fair value of plan assets at end of year
Funded status	(4,542)	(4,255)
Accrued benefit liabilities	(4,542)	(4,255)
Net actuarial loss	841	747
Prior service cost	156	187
Net amount recognized in equity – pre-tax	997	934
Net amount recognized on Consolidated Balance Sheets in Other Liabilities	(3,545)	(3,321)
Accumulated benefit obligation at year end	$ 4,007	$ 3,902