Allowance For Loan Losses (Schedule Of Aging Analysis Of Accruing And Non-Accruing Loans) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 3,134,226	$ 3,106,150
Non-accrual	13,078	10,297
Gross loans	3,155,468	3,127,410
Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,463,135	1,458,746
Non-accrual	3,783	2,814
Gross loans	1,472,916	1,468,278
Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	138,495	138,480
Non-accrual	168	168
Gross loans	139,245	139,499
Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	212,200	206,447
Non-accrual	863	1,345
Gross loans	213,687	208,484
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,286,381	1,269,520
Non-accrual	7,707	5,970
Gross loans	1,294,489	1,277,576
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	30,546	29,108
Non-accrual	557	0
Gross loans	31,137	29,162
DDA overdrafts
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	3,469	3,849
Non-accrual	0	0
Gross loans	3,994	4,411
30-59 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	6,892	9,631
30-59 days | Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	5,097	5,990
30-59 days | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	447	671
30-59 days | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	624	549
30-59 days | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	188	1,841
30-59 days | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	31	39
30-59 days | DDA overdrafts
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	505	541
60-89 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	1,127	1,070
60-89 days | Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	820	709
60-89 days | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	71	88
60-89 days | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	1
60-89 days | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	213	245
60-89 days | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	3	13
60-89 days | DDA overdrafts
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	20	14
Over 90 days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	145	262
Over 90 days | Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	81	19
Over 90 days | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	64	92
Over 90 days | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	142
Over 90 days | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	0
Over 90 days | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	0	2
Over 90 days | DDA overdrafts
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, past due	$ 0	$ 7