Allowance For Loan Losses (Schedule Of Aging Analysis Of Accruing And Non-Accruing Loans) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 3,065,233	$ 3,024,215
Financing receivable, purchase-credit impaired	148	0
Non-accrual	10,582	13,701
Gross loans	3,083,767	3,046,226
Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,448,322	1,441,086
Financing receivable, purchase-credit impaired	0	0
Non-accrual	1,608	4,302
Gross loans	1,455,578	1,451,462
Home Equity [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	138,753	141,192
Financing receivable, purchase-credit impaired	0	0
Non-accrual	153	100
Gross loans	139,534	141,965
Commercial And Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	195,599	183,615
Financing receivable, purchase-credit impaired	0	0
Non-accrual	1,571	1,958
Gross loans	197,429	185,667
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,248,666	1,221,344
Financing receivable, purchase-credit impaired	148	0
Non-accrual	7,250	7,341
Gross loans	1,256,736	1,229,516
Consumer Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	30,790	32,506
Financing receivable, purchase-credit impaired	0	0
Non-accrual	0	0
Gross loans	30,860	32,545
Demand Deposit Account Overdrafts [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	3,103	4,472
Financing receivable, purchase-credit impaired	0	0
Non-accrual	0	0
Gross loans	3,630	5,071
Commercial Industrial Loans And Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Gross loans	1,454,165	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	6,995	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	5,081	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	408	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	253	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	672	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	60	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	521	595
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	659	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	527	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	119	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	6	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	0	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	1	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	6	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	150	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	40	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	101	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	9	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