Allowance For Loan Losses (Schedule Of Aging Analysis Of Accruing And Non-Accruing Loans) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 3,056,585	$ 3,024,215
Financing receivable, purchase-credit impaired	250	0
Non-accrual	11,418	13,701
Gross loans	3,074,173	3,046,226
Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,438,109	1,441,086
Financing receivable, purchase-credit impaired	0	0
Non-accrual	2,810	4,302
Gross loans	1,444,795	1,451,462
Home Equity [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	138,750	141,192
Financing receivable, purchase-credit impaired	0	0
Non-accrual	114	100
Gross loans	139,165	141,965
Commercial And Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	203,046	183,615
Financing receivable, purchase-credit impaired	0	0
Non-accrual	1,353	1,958
Gross loans	205,011	185,667
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,241,951	1,221,344
Financing receivable, purchase-credit impaired	250	0
Non-accrual	7,141	7,341
Gross loans	1,250,106	1,229,516
Consumer Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	32,006	32,506
Financing receivable, purchase-credit impaired	0	0
Non-accrual	0	0
Gross loans	32,043	32,545
Demand Deposit Account Overdrafts [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,723	4,472
Financing receivable, purchase-credit impaired	0	0
Non-accrual	0	0
Gross loans	3,053	5,071
Commercial Industrial Loans And Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Gross loans	1,455,117	1,415,183
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	4,808	7,067
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	3,455	5,364
Financing Receivables, 30 to 59 Days Past Due [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	205	423
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial And Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	562	94
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	239	553
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	28	38
Financing Receivables, 30 to 59 Days Past Due [Member] | Demand Deposit Account Overdrafts [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	319	595
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	1,077	861
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	386	637
Financing Receivables, 60 to 89 Days Past Due [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	96	219
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial And Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	50	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	525	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	9	1
Financing Receivables, 60 to 89 Days Past Due [Member] | Demand Deposit Account Overdrafts [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	11	4
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	35	382
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	35	73
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	31
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial And Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	278
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Demand Deposit Account Overdrafts [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	$ 0	$ 0