Allowance For Loan Losses (Schedule Of Aging Analysis Of Accruing And Non-Accruing Loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 3,087,670	$ 3,024,215
Purchased-Credit Impaired	147	0
Non-accrual	10,673	13,701
Gross loans	3,105,912	3,046,226
Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,458,091	1,441,086
Purchased-Credit Impaired	0	0
Non-accrual	2,556	4,302
Gross loans	1,465,942	1,451,462
Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	138,737	141,192
Purchased-Credit Impaired	0	0
Non-accrual	92	100
Gross loans	139,702	141,965
Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	203,093	183,615
Purchased-Credit Impaired	0	0
Non-accrual	1,325	1,958
Gross loans	204,722	185,667
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,253,686	1,221,344
Purchased-Credit Impaired	147	0
Non-accrual	6,700	7,341
Gross loans	1,260,906	1,229,516
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	30,298	32,506
Purchased-Credit Impaired	0	0
Non-accrual	0	0
Gross loans	30,323	32,545
DDA overdrafts
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	3,765	4,472
Purchased-Credit Impaired	0	0
Non-accrual	0	0
Gross loans	4,317	5,071
Commercial Industrial Loans And Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Gross loans	1,465,628	1,415,183
30-59 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	6,590	7,067
30-59 days | Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	4,684	5,364
30-59 days | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	797	423
30-59 days | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	304	94
30-59 days | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	240	553
30-59 days | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	23	38
30-59 days | DDA overdrafts
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	542	595
60-89 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	810	861
60-89 days | Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	611	637
60-89 days | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	57	219
60-89 days | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	0
60-89 days | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	133	0
60-89 days | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	2	1
60-89 days | DDA overdrafts
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	7	4
Over 90 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	22	382
Over 90 days | Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	73
Over 90 days | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	19	31
Over 90 days | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	0
Over 90 days | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	278
Over 90 days | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	0
Over 90 days | DDA overdrafts
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	$ 3	$ 0