Loans And Allowance For Loan Losses (Aging Information On Past Due And Accruing Loans) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	$ 14,128,904	$ 14,038,417
30 - 89 Days Past Due	103,679	72,687
90 Days Past Due and Still Accruing	16,532	16,658
Non-accrual loans	11,133	12,536
Total	14,260,248	14,140,298
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	5,257,682	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	5,240,438	5,086,912
30 - 89 Days Past Due	8,279	10,057
90 Days Past Due and Still Accruing	537	473
Non-accrual loans	8,428	8,985
Total	5,257,682	5,106,427
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	909,784	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	858,371	867,692
30 - 89 Days Past Due	51,410	1,963
90 Days Past Due and Still Accruing	0	0
Non-accrual loans	3	4
Total	909,784	869,659
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,867,831	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	2,865,016	2,867,347
30 - 89 Days Past Due	1,865	6,704
90 Days Past Due and Still Accruing	0	22
Non-accrual loans	950	1,715
Total	2,867,831	2,875,788
Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,160,515	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	2,148,788	2,118,045
30 - 89 Days Past Due	7,281	6,041
90 Days Past Due and Still Accruing	2,694	1,165
Non-accrual loans	1,752	1,832
Total	2,160,515	2,127,083
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	1,927,623	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	1,900,464	1,916,320
30 - 89 Days Past Due	24,503	35,608
90 Days Past Due and Still Accruing	2,656	3,644
Non-accrual loans	0	0
Total	1,927,623	1,955,572
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	357,406	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	356,410	374,830
30 - 89 Days Past Due	413	875
90 Days Past Due and Still Accruing	583	694
Non-accrual loans	0	0
Total	357,406	376,399
Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	776,333	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	756,615	792,334
30 - 89 Days Past Due	9,656	11,140
90 Days Past Due and Still Accruing	10,062	10,660
Non-accrual loans	0	0
Total	776,333	814,134
Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	3,074	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	2,802	14,937
30 - 89 Days Past Due	272	299
90 Days Past Due and Still Accruing	0	0
Non-accrual loans	0	0
Total	$ 3,074	$ 15,236