Loans And Allowance For Credit Losses (Aging Information On Past Due And Accruing Loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	$ 16,296,692	$ 14,627,638
30 - 89 Days Past Due	69,529	80,100
90 Days Past Due and Still Accruing	14,436	19,859
Non-accrual loans	40,270	10,220
Total	16,420,927	14,737,817
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	6,683,413	5,565,449
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	1,009,729	899,377
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,993,192	2,833,554
Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,753,867	2,354,760
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,006,360	1,964,145
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	324,203	349,251
Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	647,893	764,977
Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,270	6,304
Commercial Portfolio Segment [Member] | Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	6,636,383	5,545,104
30 - 89 Days Past Due	7,106	12,064
90 Days Past Due and Still Accruing	2,629	792
Non-accrual loans	37,295	7,489
Commercial Portfolio Segment [Member] | Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	991,404	882,826
30 - 89 Days Past Due	18,320	13,046
90 Days Past Due and Still Accruing	4	3,503
Non-accrual loans	1	2
Commercial Portfolio Segment [Member] | Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	2,987,992	2,830,494
30 - 89 Days Past Due	4,137	2,030
90 Days Past Due and Still Accruing	0	0
Non-accrual loans	1,063	1,030
Personal Banking Portfolio Segment [Member] | Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	2,743,260	2,345,243
30 - 89 Days Past Due	6,029	6,129
90 Days Past Due and Still Accruing	2,667	1,689
Non-accrual loans	1,911	1,699
Personal Banking Portfolio Segment [Member] | Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	1,983,820	1,928,082
30 - 89 Days Past Due	20,329	34,053
90 Days Past Due and Still Accruing	2,211	2,010
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	322,572	347,258
30 - 89 Days Past Due	1,237	1,743
90 Days Past Due and Still Accruing	394	250
Non-accrual loans	0	0
Personal Banking Portfolio Segment [Member] | Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	629,181	742,659
30 - 89 Days Past Due	12,181	10,703
90 Days Past Due and Still Accruing	6,531	11,615
Non-accrual loans	0	0
Personal Banking Portfolio Segment [Member] | Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	2,080	5,972
30 - 89 Days Past Due	190	332
90 Days Past Due and Still Accruing	0	0
Non-accrual loans	$ 0	$ 0