Allowance For Loan Losses (Schedule Of Non-Commercial Loans By Payment Performance) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Total	$ 2,957,912	$ 2,862,534
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	1,445,242	1,383,133
Residential Real Estate [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	1,441,109	1,379,797
Residential Real Estate [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	4,133	3,336
Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	141,616	147,036
Home Equity [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	141,462	146,877
Home Equity [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	154	159
Consumer Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	33,614	36,083
Consumer Loan [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	33,614	36,049
Consumer Loan [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	0	34
Demand Deposit Account Overdrafts [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	2,965	3,361
Demand Deposit Account Overdrafts [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	2,691	3,361
Demand Deposit Account Overdrafts [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	274	0
Noncommercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	1,623,437	1,569,613
Noncommercial Loans [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	1,618,876	1,566,084
Noncommercial Loans [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Total	$ 4,561	$ 3,529