Derivative Instruments (Fair Value Of Derivative Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Customer Counterparties Loan Interest Rate Swap Assets | Non-hedging interest rate derivatives: | Other Assets
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 318,072	$ 234,806
Derivative, Fair Value	7,570	7,352
Customer Counterparties Loan Interest Rate Swap Liabilities | Non-hedging interest rate derivatives: | Other Liabilities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	225,990	207,201
Derivative, Fair Value	6,881	8,111
Financial Institution Counterparties Loan Interest Rate Swap Asset | Non-hedging interest rate derivatives: | Other Assets
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	232,665	207,201
Derivative, Fair Value	6,903	8,111
Financial Institution Counterparties Loan Interest Rate Swap Liabilities | Non-hedging interest rate derivatives: | Other Liabilities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	311,484	241,995
Derivative, Fair Value	7,575	7,360
Financial Institution Counterparties Loan Interest Rate Swap Liabilities | Derivatives designated as hedges of fair value: | Other Liabilities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	4,326	4,626
Derivative, Fair Value	$ 2	$ 12