Allowance For Loan Losses (Schedule Of Non-Commercial Loans By Payment Performance) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 3,519,367	$ 3,587,608
Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,644,494	1,635,338
Residential real estate | Performing [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,642,063	1,630,892
Residential real estate | Non-Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,431	4,446
Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Total	150,676	153,496
Home equity | Performing [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	150,499	153,334
Home equity | Non-Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	177	162
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total	53,356	51,190
Consumer | Performing [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	53,356	51,188
Consumer | Non-Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	2
DDA overdrafts
Financing Receivable, Credit Quality Indicator [Line Items]
Total	3,922	6,328
DDA overdrafts | Performing [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	3,921	6,322
DDA overdrafts | Non-Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1	6
Total
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,852,448	1,846,352
Total | Performing [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,849,839	1,841,736
Total | Non-Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 2,609	$ 4,616