Short-Term Borrowings (Schedule Of Short-Term Debt) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Short-term Debt [Line Items]
Maximum outstanding at any month end	$ 58,747	$ 98,568	$ 63,916
Average outstanding	35,243	37,559	28,673
Overnight Borrowings [Member]
Short-term Debt [Line Items]
Maximum outstanding at any month end	58,747	76,366	46,737
Average outstanding	$ 35,243	$ 27,893	$ 18,399
Weighted-average rate during the year	2.49%	2.38%	1.09%
Rate at year-end	1.81%	2.62%	1.56%
Repurchase Agreements [Member]
Short-term Debt [Line Items]
Maximum outstanding at any month end		$ 22,202	$ 17,179
Average outstanding		$ 9,666	$ 10,274
Weighted-average rate during the year		0.16%	0.20%
Rate at year-end			0.18%