Loans And Allowance For Loan Losses (Aging Information On Past Due And Accruing Loans) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 days Past Due	$ 14,038,417	$ 13,897,272
30 – 89 Days Past Due	72,687	56,292
90 Days Past Due and Still Accruing	16,658	18,127
Non-accrual	12,536	11,983
Total	14,140,298	13,983,674
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	5,106,427	4,958,554
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	869,659	968,820
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,875,788	2,697,452
Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,127,083	2,062,787
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	1,955,572	2,104,487
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	376,399	400,587
Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	814,134	783,864
Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	15,236	7,123
Commercial Portfolio Segment [Member] | Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 days Past Due	5,086,912	4,949,148
30 – 89 Days Past Due	10,057	3,085
90 Days Past Due and Still Accruing	473	374
Non-accrual	8,985	5,947
Commercial Portfolio Segment [Member] | Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 days Past Due	867,692	967,321
30 – 89 Days Past Due	1,963	1,473
90 Days Past Due and Still Accruing	0	21
Non-accrual	4	5
Commercial Portfolio Segment [Member] | Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 days Past Due	2,867,347	2,694,234
30 – 89 Days Past Due	6,704	482
90 Days Past Due and Still Accruing	22	0
Non-accrual	1,715	2,736
Personal Banking Portfolio Segment [Member] | Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 days Past Due	2,118,045	2,050,787
30 – 89 Days Past Due	6,041	6,218
90 Days Past Due and Still Accruing	1,165	3,321
Non-accrual	1,832	2,461
Personal Banking Portfolio Segment [Member] | Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 days Past Due	1,916,320	2,067,025
30 – 89 Days Past Due	35,608	32,674
90 Days Past Due and Still Accruing	3,644	3,954
Non-accrual	0	834
Personal Banking Portfolio Segment [Member] | Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 days Past Due	374,830	397,349
30 – 89 Days Past Due	875	1,962
90 Days Past Due and Still Accruing	694	1,276
Non-accrual	0	0
Personal Banking Portfolio Segment [Member] | Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 days Past Due	792,334	764,568
30 – 89 Days Past Due	11,140	10,115
90 Days Past Due and Still Accruing	10,660	9,181
Non-accrual	0	0
Personal Banking Portfolio Segment [Member] | Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 days Past Due	14,937	6,840
30 – 89 Days Past Due	299	283
90 Days Past Due and Still Accruing	0	0
Non-accrual	$ 0	$ 0