Allowance For Loan Losses (Schedule of Non-Commercial Loans By Payment Performance) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Loans, Total	$ 3,127,410	$ 3,046,226
Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Loans, Total	1,468,278	1,451,462
Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans, Total	139,499	141,965
Consumer Loan
Financing Receivable, Recorded Investment [Line Items]
Loans, Total	29,162	32,545
DDA Overdrafts
Financing Receivable, Recorded Investment [Line Items]
Loans, Total	4,411	5,071
Non-commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, Total	1,641,350	1,631,043
Performing
Financing Receivable, Recorded Investment [Line Items]
Loans, Total	1,638,257	1,626,537
Performing | Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Loans, Total	1,465,445	1,447,087
Performing | Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans, Total	139,239	141,834
Performing | Consumer Loan
Financing Receivable, Recorded Investment [Line Items]
Loans, Total	29,162	32,545
Performing | DDA Overdrafts
Financing Receivable, Recorded Investment [Line Items]
Loans, Total	4,411	5,071
Non-Performing
Financing Receivable, Recorded Investment [Line Items]
Loans, Total	3,093	4,506
Non-Performing | Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Loans, Total	2,833	4,375
Non-Performing | Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans, Total	260	131
Non-Performing | Consumer Loan
Financing Receivable, Recorded Investment [Line Items]
Loans, Total	0	0
Non-Performing | DDA Overdrafts
Financing Receivable, Recorded Investment [Line Items]
Loans, Total	$ 0	$ 0