Loans And Allowance For Loan Losses (Aging Information On Past Due And Accruing Loans) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	$ 12,997,717	$ 12,344,207
30 - 89 Days Past Due	53,755	49,443
90 Days Past Due and Still Accruing	15,892	16,467
Non-accrual loans	24,524	26,575
Total	13,091,888	12,436,692
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	4,840,248	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	4,815,328	4,384,149
30 - 89 Days Past Due	11,924	2,306
90 Days Past Due and Still Accruing	280	564
Non-accrual loans	12,716	10,874
Total	4,840,248	4,397,893
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	819,896	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	815,890	617,838
30 - 89 Days Past Due	1,836	3,142
90 Days Past Due and Still Accruing	0	0
Non-accrual loans	2,170	3,090
Total	819,896	624,070
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,399,271	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	2,388,292	2,340,919
30 - 89 Days Past Due	3,743	6,762
90 Days Past Due and Still Accruing	2,000	0
Non-accrual loans	5,236	7,863
Total	2,399,271	2,355,544
Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	1,927,340	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	1,913,469	1,901,330
30 - 89 Days Past Due	7,083	7,117
90 Days Past Due and Still Accruing	2,495	3,081
Non-accrual loans	4,293	4,425
Total	1,927,340	1,915,953
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	1,939,486	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	1,919,044	1,903,389
30 - 89 Days Past Due	17,896	18,273
90 Days Past Due and Still Accruing	2,546	2,703
Non-accrual loans	0	0
Total	1,939,486	1,924,365
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	408,301	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	403,831	427,998
30 - 89 Days Past Due	2,993	2,641
90 Days Past Due and Still Accruing	1,368	2,019
Non-accrual loans	109	323
Total	408,301	432,981
Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	753,166	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	737,946	762,750
30 - 89 Days Past Due	8,017	8,894
90 Days Past Due and Still Accruing	7,203	8,100
Non-accrual loans	0	0
Total	753,166	779,744
Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	4,180	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	3,917	5,834
30 - 89 Days Past Due	263	308
90 Days Past Due and Still Accruing	0	0
Non-accrual loans	0	0
Total	$ 4,180	$ 6,142