Contingent Liabilities And Commitments (Summary Of Commitments And Contingent Liabilities) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Loss Contingencies [Line Items]
Commitments and contingent liabilities	$ 336,842		$ 336,283
Losses on commitments	0	$ 0
Reserve for commitments	0	$ 0
Commitments To Extend Credit [Member]
Loss Contingencies [Line Items]
Commitments and contingent liabilities	333,067		331,974
Standby Letters Of Credit [Member]
Loss Contingencies [Line Items]
Commitments and contingent liabilities	$ 3,775		$ 4,309