Net Periodic Benefit Costs (Schedule Of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 50	$ 55
Expected return on plan assets	(81)	(69)
Amortization of the net loss	25	24
Net periodic cost (benefit)	(6)	10
Supplemental Executive Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	39	36
Interest cost	38	50
Amortization of prior service cost	8	8
Amortization of the net loss	88	59
Net periodic cost (benefit)	$ 173	$ 153