Loans And Allowance For Loan Losses (Summary Of Activity In The Allowance For Loan Losses) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	$ 159,532	$ 155,932
Provision	10,396	11,128
Loans charged off	13,731	12,876
Less recoveries on loans	3,335	3,648
Net loan charge-offs (recoveries)	10,396	9,228
Balance at end of period	159,532	157,832
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	93,704	91,361
Provision	(894)	1,113
Loans charged off	366	546
Less recoveries on loans	621	1,023
Net loan charge-offs (recoveries)	(255)	(477)
Balance at end of period	93,065	92,951
Personal Banking Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	65,828	64,571
Provision	11,290	10,015
Loans charged off	13,365	12,330
Less recoveries on loans	2,714	2,625
Net loan charge-offs (recoveries)	10,651	9,705
Balance at end of period	$ 66,467	$ 64,881