Loans And Allowance For Loan Losses (Aging Information On Past Due And Accruing Loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	$ 13,148,745	$ 12,344,207
30 - 89 Days Past Due	48,935	49,443
90 Days Past Due and Still Accruing	16,916	16,467
Non-accrual loans	15,645	26,575
Total	13,230,241	12,436,692
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	4,770,883	4,397,893
Business [Member] | Commercial Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	4,758,519	4,384,149
30 - 89 Days Past Due	3,100	2,306
90 Days Past Due and Still Accruing	506	564
Non-accrual loans	8,758	10,874
Total	4,770,883	4,397,893
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	800,545	624,070
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	794,731	617,838
30 - 89 Days Past Due	2,357	3,142
90 Days Past Due and Still Accruing	2,147	0
Non-accrual loans	1,310	3,090
Total	800,545	624,070
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,520,528	2,355,544
Real Estate - Business [Member] | Commercial Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	2,513,270	2,340,919
30 - 89 Days Past Due	5,011	6,762
90 Days Past Due and Still Accruing	327	0
Non-accrual loans	1,920	7,863
Total	2,520,528	2,355,544
Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	1,968,005	1,915,953
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	1,954,889	1,901,330
30 - 89 Days Past Due	6,901	7,117
90 Days Past Due and Still Accruing	2,581	3,081
Non-accrual loans	3,634	4,425
Total	1,968,005	1,915,953
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	1,972,969	1,924,365
Consumer [Member] | Personal Banking Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	1,951,011	1,903,389
30 - 89 Days Past Due	19,510	18,273
90 Days Past Due and Still Accruing	2,448	2,703
Non-accrual loans	0	0
Total	1,972,969	1,924,365
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	417,591	432,981
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	414,251	427,998
30 - 89 Days Past Due	2,246	2,641
90 Days Past Due and Still Accruing	1,071	2,019
Non-accrual loans	23	323
Total	417,591	432,981
Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	760,022	779,744
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	742,820	762,750
30 - 89 Days Past Due	9,366	8,894
90 Days Past Due and Still Accruing	7,836	8,100
Non-accrual loans	0	0
Total	760,022	779,744
Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	19,698	6,142
Overdrafts [Member] | Personal Banking Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	19,254	5,834
30 - 89 Days Past Due	444	308
90 Days Past Due and Still Accruing	0	0
Non-accrual loans	0	0
Total	$ 19,698	$ 6,142