Loans And Allowance For Loan Losses (Aging Information On Past Due And Accruing Loans) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	$ 12,594,793	$ 12,344,207
30 - 89 Days Past Due	58,350	49,443
90 Days Past Due and Still Accruing	15,360	16,467
Non-accrual	29,367	26,575
Total	12,697,870	12,436,692
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	4,575,081	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	4,551,468	4,384,149
30 - 89 Days Past Due	6,806	2,306
90 Days Past Due and Still Accruing	709	564
Non-accrual	16,098	10,874
Total	4,575,081	4,397,893
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	745,369	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	734,547	617,838
30 - 89 Days Past Due	8,112	3,142
90 Days Past Due and Still Accruing	0	0
Non-accrual	2,710	3,090
Total	745,369	624,070
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,395,933	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	2,379,738	2,340,919
30 - 89 Days Past Due	9,961	6,762
90 Days Past Due and Still Accruing	0	0
Non-accrual	6,234	7,863
Total	2,395,933	2,355,544
Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	1,903,969	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	1,890,775	1,901,330
30 - 89 Days Past Due	6,477	7,117
90 Days Past Due and Still Accruing	2,512	3,081
Non-accrual	4,205	4,425
Total	1,903,969	1,915,953
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	1,904,320	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	1,884,817	1,903,389
30 - 89 Days Past Due	16,726	18,273
90 Days Past Due and Still Accruing	2,777	2,703
Non-accrual	0	0
Total	1,904,320	1,924,365
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	423,005	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	419,114	427,998
30 - 89 Days Past Due	2,147	2,641
90 Days Past Due and Still Accruing	1,624	2,019
Non-accrual	120	323
Total	423,005	432,981
Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	744,364	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	728,741	762,750
30 - 89 Days Past Due	7,885	8,894
90 Days Past Due and Still Accruing	7,738	8,100
Non-accrual	0	0
Total	744,364	779,744
Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	5,829	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	5,593	5,834
30 - 89 Days Past Due	236	308
90 Days Past Due and Still Accruing	0	0
Non-accrual	0	0
Total	$ 5,829	$ 6,142