Loans And Allowance For Loan Losses (Allowance For Loan Losses And Related Loan Balance Disaggregated On The Basis Of Impairment Methodology) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Loans And Allowance For Loan Losses [Line Items]
Loans And Leases Receivable Excluding Impaired Financing Receivables Recorded Investment	$ 14,036,550	$ 14,061,682
Impaired Financing Receivable, Recorded Investment	84,172	78,616
Loans and Leases Receivable Allowance Excluding Impaired Financing Receivable Related Allowance	158,039	157,236
Impaired Financing Receivable, Related Allowance	2,643	2,696
Commercial Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans And Leases Receivable Excluding Impaired Financing Receivables Recorded Investment	8,893,685	8,790,378
Impaired Financing Receivable, Recorded Investment	66,739	61,496
Loans and Leases Receivable Allowance Excluding Impaired Financing Receivable Related Allowance	91,923	91,089
Impaired Financing Receivable, Related Allowance	1,720	1,780
Personal Banking Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans And Leases Receivable Excluding Impaired Financing Receivables Recorded Investment	5,142,865	5,271,304
Impaired Financing Receivable, Recorded Investment	17,433	17,120
Loans and Leases Receivable Allowance Excluding Impaired Financing Receivable Related Allowance	66,116	66,147
Impaired Financing Receivable, Related Allowance	$ 923	$ 916