Short-Term Borrowings (Schedule Of Short-Term Debt) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Short-term Debt [Line Items]
Maximum outstanding at any month end	$ 161,950	$ 58,747	$ 98,568
Average outstanding	$ 49,165	$ 35,243	$ 37,559
Rate at year-end
Overnight Borrowings [Member]
Short-term Debt [Line Items]
Maximum outstanding at any month end	$ 9,159	$ 58,747	$ 76,366
Average outstanding	$ 4,175	$ 35,243	$ 27,893
Weighted-average rate during the year	2.13%	2.49%	2.38%
Rate at year-end		1.81%	2.62%
Paycheck Protection Program Liquidity Facility [Member]
Short-term Debt [Line Items]
Maximum outstanding at any month end	$ 152,791
Average outstanding	$ 44,990
Weighted-average rate during the year	0.35%
Rate at year-end
Repurchase Agreements [Member]
Short-term Debt [Line Items]
Maximum outstanding at any month end			$ 22,202
Average outstanding			$ 9,666
Weighted-average rate during the year			0.16%
Rate at year-end