Loans And Allowance For Credit Losses (Aging Information On Past Due And Accruing Loans) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	$ 15,399,709	$ 15,116,475
30 - 89 Days Past Due	40,300	39,001
90 Days Past Due and Still Accruing	10,670	11,726
Non-accrual loans	8,335	9,157
Total	15,459,014	15,176,359
Business
Loans And Allowance For Loan Losses [Line Items]
Total	5,508,508	5,303,535
Real estate - construction and land
Loans And Allowance For Loan Losses [Line Items]
Total	1,144,411	1,118,266
Real estate - business
Loans And Allowance For Loan Losses [Line Items]
Total	3,109,668	3,058,837
Real estate - personal
Loans And Allowance For Loan Losses [Line Items]
Total	2,820,076	2,805,401
Consumer
Loans And Allowance For Loan Losses [Line Items]
Total	2,053,160	2,032,225
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	264,401	275,945
Consumer credit card
Loans And Allowance For Loan Losses [Line Items]
Total	544,579	575,410
Overdrafts
Loans And Allowance For Loan Losses [Line Items]
Total	14,211	6,740
Commercial Portfolio Segment [Member] | Business
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	5,494,664	5,292,125
30 - 89 Days Past Due	6,747	3,621
90 Days Past Due and Still Accruing	341	477
Non-accrual loans	6,756	7,312
Commercial Portfolio Segment [Member] | Real estate - construction and land
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	1,144,411	1,117,434
30 - 89 Days Past Due	0	832
90 Days Past Due and Still Accruing	0	0
Non-accrual loans	0	0
Commercial Portfolio Segment [Member] | Real estate - business
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	3,105,452	3,058,566
30 - 89 Days Past Due	4,026	57
90 Days Past Due and Still Accruing	0	0
Non-accrual loans	190	214
Personal Banking Portfolio Segment [Member] | Real estate - personal
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	2,811,330	2,796,662
30 - 89 Days Past Due	5,076	4,125
90 Days Past Due and Still Accruing	2,281	2,983
Non-accrual loans	1,389	1,631
Personal Banking Portfolio Segment [Member] | Consumer
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	2,031,680	2,005,556
30 - 89 Days Past Due	18,890	24,458
90 Days Past Due and Still Accruing	2,590	2,211
Non-accrual loans	0	0
Personal Banking Portfolio Segment [Member] | Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	262,799	274,372
30 - 89 Days Past Due	748	772
90 Days Past Due and Still Accruing	854	801
Non-accrual loans	0	0
Personal Banking Portfolio Segment [Member] | Consumer credit card
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	535,482	565,335
30 - 89 Days Past Due	4,493	4,821
90 Days Past Due and Still Accruing	4,604	5,254
Non-accrual loans	0	0
Personal Banking Portfolio Segment [Member] | Overdrafts
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	13,891	6,425
30 - 89 Days Past Due	320	315
90 Days Past Due and Still Accruing	0	0
Non-accrual loans	$ 0	$ 0