Loans And Allowance For Loan Losses (Summary Of Activity In The Allowance For Loan Losses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	$ 159,532	$ 157,832	$ 159,532	$ 155,932
Provision	9,999	10,704	30,438	32,590
Loans charged off	13,000	13,970	40,416	40,792
Less recoveries on loans	3,201	3,266	10,178	10,102
Net loan charge-offs (recoveries)	9,799	10,704	30,238	30,690
Balance at end of period	159,732	157,832	159,732	157,832
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	93,851	92,739	93,704	91,361
Provision	411	24	2	1,026
Loans charged off	485	378	1,213	1,455
Less recoveries on loans	314	651	1,598	2,104
Net loan charge-offs (recoveries)	171	(273)	(385)	(649)
Balance at end of period	94,091	93,036	94,091	93,036
Personal Banking Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	65,681	65,093	65,828	64,571
Provision	9,588	10,680	30,436	31,564
Loans charged off	12,515	13,592	39,203	39,337
Less recoveries on loans	2,887	2,615	8,580	7,998
Net loan charge-offs (recoveries)	9,628	10,977	30,623	31,339
Balance at end of period	$ 65,641	$ 64,796	$ 65,641	$ 64,796