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	Dec. 31, 2017	Dec. 31, 2016
Loans And Allowance For Loan Losses [Line Items]
Impaired loans, Allowance for loan losses	$ 4,243	$ 3,109
All other loans, Allowance for loan losses	155,289	152,823
Impaired loans, Loans outstanding	114,795	64,532
All other loans, Loans outstanding	13,868,879	13,348,204
Commercial Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Impaired loans, Allowance for loan losses	3,067	1,817
All other loans, Allowance for loan losses	90,637	89,544
Impaired loans, Loans outstanding	92,613	44,795
All other loans, Loans outstanding	8,532,213	8,166,180
Personal Banking Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Impaired loans, Allowance for loan losses	1,176	1,292
All other loans, Allowance for loan losses	64,652	63,279
Impaired loans, Loans outstanding	22,182	19,737
All other loans, Loans outstanding	$ 5,336,666	$ 5,182,024