Allowance For Loan Losses (Schedule Of Non-Commercial Loans By Payment Performance) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Total	$ 3,083,767	$ 3,046,226
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	1,455,578	1,451,462
Residential Real Estate [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	1,453,930	1,447,087
Residential Real Estate [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	1,648	4,375
Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	139,534	141,965
Home Equity [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	139,381	141,834
Home Equity [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	153	131
Consumer Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	30,860	32,545
Consumer Loan [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	30,860	32,545
Consumer Loan [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	0	0
Demand Deposit Account Overdrafts [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	3,630	5,071
Demand Deposit Account Overdrafts [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	3,630	5,071
Demand Deposit Account Overdrafts [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	0	0
Noncommercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	1,629,602	1,631,043
Noncommercial Loans [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	1,627,801	1,626,537
Noncommercial Loans [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	$ 1,801	$ 4,506