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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance at beginning of period	$ 161,182	$ 159,532	$ 159,932	$ 159,532
Provision	10,963	9,999	35,232	30,438
Loans charged off	14,480	13,000	43,669	40,416
Less recoveries on loans	3,017	3,201	9,187	10,178
Net loan charge-offs (recoveries)	11,463	9,799	34,482	30,238
Balance at end of period	160,682	159,732	160,682	159,732
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance at beginning of period	91,808	93,851	92,869	93,704
Provision	553	411	55	2
Loans charged off	490	485	1,436	1,213
Less recoveries on loans	199	314	582	1,598
Net loan charge-offs (recoveries)	291	171	854	(385)
Balance at end of period	92,070	94,091	92,070	94,091
Personal Banking Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance at beginning of period	69,374	65,681	67,063	65,828
Provision	10,410	9,588	35,177	30,436
Loans charged off	13,990	12,515	42,233	39,203
Less recoveries on loans	2,818	2,887	8,605	8,580
Net loan charge-offs (recoveries)	11,172	9,628	33,628	30,623
Balance at end of period	$ 68,612	$ 65,641	$ 68,612	$ 65,641