Allowance For Loan Losses (Schedule Of Aging Analysis Of Accruing And Non-Accruing Loans) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 3,106,150	$ 3,024,215
Non-accrual	10,297	13,701
Gross loans	3,127,410	3,046,226
Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,458,746	1,441,086
Non-accrual	2,814	4,302
Gross loans	1,468,278	1,451,462
Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	138,480	141,192
Non-accrual	168	100
Gross loans	139,499	141,965
Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	206,447	183,615
Non-accrual	1,345	1,958
Gross loans	208,484	185,667
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,269,520	1,221,344
Non-accrual	5,970	7,341
Gross loans	1,277,576	1,229,516
Consumer Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	29,108	32,506
Non-accrual	0	0
Gross loans	29,162	32,545
DDA Overdrafts
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	3,849	4,472
Non-accrual	0	0
Gross loans	4,411	5,071
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	9,631	7,067
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	5,990	5,364
Financing Receivables, 30 to 59 Days Past Due [Member] | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	671	423
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	549	94
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	1,841	553
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	39	38
Financing Receivables, 30 to 59 Days Past Due [Member] | DDA Overdrafts
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	541	595
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	1,070	861
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	709	637
Financing Receivables, 60 to 89 Days Past Due [Member] | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	88	219
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	1	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	245	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	13	1
Financing Receivables, 60 to 89 Days Past Due [Member] | DDA Overdrafts
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	14	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	262	382
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	19	73
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	92	31
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	142	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial real estate
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
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	2	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | DDA Overdrafts
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	$ 7	$ 0