Allowance For Loan Losses (Schedule Of Aging Analysis Of Accruing And Non-Accruing Loans) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Past Due [Line Items]
Current	$ 3,593,213	$ 3,559,926
Non-accrual	11,490	14,551
Gross loans	3,616,099	3,587,608
Residential real estate
Financing Receivable, Past Due [Line Items]
Current	1,629,519	1,621,073
Non-accrual	3,393	4,275
Gross loans	1,640,396	1,635,338
Home equity
Financing Receivable, Past Due [Line Items]
Current	147,441	152,083
Non-accrual	531	138
Gross loans	148,928	153,496
Commercial and industrial
Financing Receivable, Past Due [Line Items]
Current	306,375	284,140
Non-accrual	1,182	1,676
Gross loans	308,015	286,314
Commercial real estate
Financing Receivable, Past Due [Line Items]
Current	1,451,773	1,445,896
Non-accrual	6,384	8,461
Gross loans	1,459,737	1,454,942
Consumer Loan
Financing Receivable, Past Due [Line Items]
Current	54,075	50,894
Non-accrual	0	1
Gross loans	54,263	51,190
DDA Overdrafts
Financing Receivable, Past Due [Line Items]
Current	4,030	5,840
Non-accrual	0	0
Gross loans	4,760	6,328
Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	9,155	11,451
Financial Asset, 30 to 59 Days Past Due [Member] | Residential real estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	5,758	8,607
Financial Asset, 30 to 59 Days Past Due [Member] | Home equity
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	840	1,240
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	243	397
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial real estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,514	487
Financial Asset, 30 to 59 Days Past Due [Member] | Consumer Loan
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	156	253
Financial Asset, 30 to 59 Days Past Due [Member] | DDA Overdrafts
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	644	467
Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,974	1,423
Financial Asset, 60 to 89 Days Past Due [Member] | Residential real estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,643	1,213
Financial Asset, 60 to 89 Days Past Due [Member] | Home equity
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	116	11
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	31	49
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial real estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	66	94
Financial Asset, 60 to 89 Days Past Due [Member] | Consumer Loan
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	32	41
Financial Asset, 60 to 89 Days Past Due [Member] | DDA Overdrafts
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	86	15
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	267	257
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Residential real estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	83	170
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Home equity
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	24
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	184	52
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial real estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	4
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Loan
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	1
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | DDA Overdrafts
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	$ 0	$ 6