Employee Benefits And Deferred Compensation Plans (Schedule Of Net Periodic Benefit Costs, Employee Pension Plan) (Details) - Pension Benefits [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Service cost
Interest cost	216	221	205
Expected return on plan assets	(275)	(263)	(308)
Net amortization and deferral	92	85	71
Net periodic benefit cost	$ 33	$ 43	$ (32)