Loans And Allowance For Loan Losses (Aging Information On Past Due And Accruing Loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	$ 14,358,064	$ 14,038,417
30 - 89 Days Past Due	76,489	72,687
90 Days Past Due and Still Accruing	16,308	16,658
Non-accrual loans	11,733	12,536
Total	14,462,594	14,140,298
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	5,393,268	5,106,427
Business [Member] | Commercial Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	5,365,188	5,086,912
30 - 89 Days Past Due	19,334	10,057
90 Days Past Due and Still Accruing	993	473
Non-accrual loans	7,753	8,985
Total	5,393,268	5,106,427
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	932,737	869,659
Real Estate - Construction And Land [Member] | Commercial Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	925,805	867,692
30 - 89 Days Past Due	6,918	1,963
90 Days Past Due and Still Accruing	11	0
Non-accrual loans	3	4
Total	932,737	869,659
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,833,146	2,875,788
Real Estate - Business [Member] | Commercial Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	2,824,165	2,867,347
30 - 89 Days Past Due	6,622	6,704
90 Days Past Due and Still Accruing	0	22
Non-accrual loans	2,359	1,715
Total	2,833,146	2,875,788
Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,226,663	2,127,083
Real Estate - Personal [Member] | Personal Banking Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	2,216,292	2,118,045
30 - 89 Days Past Due	6,354	6,041
90 Days Past Due and Still Accruing	2,399	1,165
Non-accrual loans	1,618	1,832
Total	2,226,663	2,127,083
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	1,953,690	1,955,572
Consumer [Member] | Personal Banking Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	1,926,310	1,916,320
30 - 89 Days Past Due	25,031	35,608
90 Days Past Due and Still Accruing	2,349	3,644
Non-accrual loans	0	0
Total	1,953,690	1,955,572
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	349,111	376,399
Revolving Home Equity [Member] | Personal Banking Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	347,956	374,830
30 - 89 Days Past Due	994	875
90 Days Past Due and Still Accruing	161	694
Non-accrual loans	0	0
Total	349,111	376,399
Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	766,743	814,134
Consumer Credit Card [Member] | Personal Banking Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	745,438	792,334
30 - 89 Days Past Due	10,910	11,140
90 Days Past Due and Still Accruing	10,395	10,660
Non-accrual loans	0	0
Total	766,743	814,134
Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	7,236	15,236
Overdrafts [Member] | Personal Banking Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	6,910	14,937
30 - 89 Days Past Due	326	299
90 Days Past Due and Still Accruing	0	0
Non-accrual loans	0	0
Total	$ 7,236	$ 15,236