Allowance For Loan Losses (Schedule Of Aging Analysis Of Accruing And Non-Accruing Loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, Past Due [Line Items]
Current	$ 3,557,167	$ 3,559,926
Non-accrual	15,197	14,551
Gross loans	3,582,571	3,587,608
Residential real estate
Financing Receivable, Past Due [Line Items]
Current	1,633,987	1,621,073
Non-accrual	2,570	4,275
Gross loans	1,643,416	1,635,338
Home equity
Financing Receivable, Past Due [Line Items]
Current	149,544	152,083
Non-accrual	469	138
Gross loans	150,808	153,496
Commercial and industrial
Financing Receivable, Past Due [Line Items]
Current	294,341	284,140
Non-accrual	2,059	1,676
Gross loans	296,927	286,314
Commercial real estate
Financing Receivable, Past Due [Line Items]
Current	1,420,608	1,445,896
Non-accrual	10,099	8,461
Gross loans	1,431,983	1,454,942
Consumer
Financing Receivable, Past Due [Line Items]
Current	54,675	50,894
Non-accrual	0	1
Gross loans	54,799	51,190
DDA overdrafts
Financing Receivable, Past Due [Line Items]
Current	4,012	5,840
Non-accrual	0	0
Gross loans	4,638	6,328
30-59 days
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	8,994	11,451
30-59 days | Residential real estate
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	5,817	8,607
30-59 days | Home equity
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	749	1,240
30-59 days | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	415	397
30-59 days | Commercial real estate
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	1,276	487
30-59 days | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	124	253
30-59 days | DDA overdrafts
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	613	467
60-89 days
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	761	1,423
60-89 days | Residential real estate
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	692	1,213
60-89 days | Home equity
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	6	11
60-89 days | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	50	49
60-89 days | Commercial real estate
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	94
60-89 days | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	41
60-89 days | DDA overdrafts
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	13	15
Over 90 days
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	452	257
Over 90 days | Residential real estate
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	350	170
Over 90 days | Home equity
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	40	24
Over 90 days | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	62	52
Over 90 days | Commercial real estate
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	4
Over 90 days | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	1
Over 90 days | DDA overdrafts
Financing Receivable, Past Due [Line Items]
Financing receivable, recorded investment, past due	$ 0	$ 6