Loans And Allowance For Loan Losses (Aging Information On Past Due And Accruing Loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	$ 12,138,379	$ 11,365,009
30 - 89 Days Past Due	45,409	49,796
90 Days Past Due and Still Accruing	14,707	13,658
Non-accrual	25,779	40,775
Total	12,224,274	11,469,238
Business [Member] | Commercial Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	4,391,674	3,946,144
30 - 89 Days Past Due	3,106	11,152
90 Days Past Due and Still Accruing	375	1,096
Non-accrual	11,699	11,560
Total	4,406,854	3,969,952
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	529,117	397,488
30 - 89 Days Past Due	1,262	827
90 Days Past Due and Still Accruing	0	35
Non-accrual	4,046	5,157
Total	534,425	403,507
Real Estate - Business [Member] | Commercial Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	2,277,384	2,266,688
30 - 89 Days Past Due	3,575	3,661
90 Days Past Due and Still Accruing	0	0
Non-accrual	5,054	17,866
Total	2,286,013	2,288,215
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	1,904,280	1,868,606
30 - 89 Days Past Due	8,695	6,618
90 Days Past Due and Still Accruing	2,695	1,676
Non-accrual	4,980	6,192
Total	1,920,650	1,883,092
Consumer [Member] | Personal Banking Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	1,867,657	1,687,285
30 - 89 Days Past Due	17,244	16,053
90 Days Past Due and Still Accruing	1,905	1,796
Non-accrual	0	0
Total	1,886,806	1,705,134
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	423,939	428,478
30 - 89 Days Past Due	2,512	1,552
90 Days Past Due and Still Accruing	2,489	843
Non-accrual	0	0
Total	428,940	430,873
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	740,124	764,599
30 - 89 Days Past Due	8,726	9,559
90 Days Past Due and Still Accruing	7,243	8,212
Non-accrual	0	0
Total	756,093	782,370
Overdrafts [Member] | Personal Banking Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	4,204	5,721
30 - 89 Days Past Due	289	374
90 Days Past Due and Still Accruing	0	0
Non-accrual	0	0
Total	$ 4,493	$ 6,095