Loans And Allowance For Loan Losses (Aging Information On Past Due And Accruing Loans) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	$ 13,488,275	$ 13,324,515
30 - 89 Days Past Due	54,523	57,542
90 Days Past Due and Still Accruing	14,908	16,396
Non-accrual loans	14,803	14,283
Total	13,572,509	13,412,736
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	4,888,011	4,776,365
Business [Member] | Commercial Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	4,875,924	4,763,274
30 - 89 Days Past Due	3,653	3,735
90 Days Past Due and Still Accruing	499	674
Non-accrual loans	7,935	8,682
Total	4,888,011	4,776,365
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	846,904	791,236
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	841,191	789,633
30 - 89 Days Past Due	5,128	1,039
90 Days Past Due and Still Accruing	0	0
Non-accrual loans	585	564
Total	846,904	791,236
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,710,595	2,643,374
Real Estate - Business [Member] | Commercial Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	2,700,322	2,639,586
30 - 89 Days Past Due	8,509	2,154
90 Days Past Due and Still Accruing	0	0
Non-accrual loans	1,764	1,634
Total	2,710,595	2,643,374
Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,013,437	2,010,397
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	2,002,185	1,995,724
30 - 89 Days Past Due	5,661	9,162
90 Days Past Due and Still Accruing	2,223	2,108
Non-accrual loans	3,368	3,403
Total	2,013,437	2,010,397
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	1,975,521	1,990,801
Consumer [Member] | Personal Banking Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	1,951,333	1,957,358
30 - 89 Days Past Due	20,950	29,783
90 Days Past Due and Still Accruing	2,087	3,660
Non-accrual loans	1,151	0
Total	1,975,521	1,990,801
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	396,542	413,634
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	394,832	411,483
30 - 89 Days Past Due	1,001	1,032
90 Days Past Due and Still Accruing	709	1,119
Non-accrual loans	0	0
Total	396,542	413,634
Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	736,766	776,465
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	717,987	757,443
30 - 89 Days Past Due	9,389	10,187
90 Days Past Due and Still Accruing	9,390	8,835
Non-accrual loans	0	0
Total	736,766	776,465
Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	4,733	10,464
Overdrafts [Member] | Personal Banking Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	4,501	10,014
30 - 89 Days Past Due	232	450
90 Days Past Due and Still Accruing	0	0
Non-accrual loans	0	0
Total	$ 4,733	$ 10,464