Short-Term Debt (Summary Of Short-Term Borrowings) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Short-term Debt [Abstract]
Federal Home Loan Bank advances	$ 54,000	$ 64,100	$ 13,000
Securities sold under agreements to repurchase	198,219	184,205	141,869
Federal Home Loan Bank advances (Avg Bal)	46,639	18,850	1,159
Securities sold under agreements to repurchase (Avg Bal)	183,890	157,215	143,847
Federal Funds purchased (Avg Bal)			193
Federal Home Loan Bank advances (Max Outstanding)	126,500	88,600	13,000
Securities sold under agreements to repurchase (Max Outstanding)	$ 257,034	$ 184,205	$ 166,507
Securities sold under agreements to repurchase (weighted average interest rate)	0.33%	0.22%	0.22%
Federal Funds purchased (weighted average interest rate)			0.64%
Federal Home Loan Bank advances (weighted average interest rate)	1.30%	0.66%	0.53%
Federal Home Loan Bank advances (end of year interest rate)	1.57%	0.77%	0.51%
Securities sold under agreements to repurchase (end of year interest rate)	0.31%	0.19%	0.20%