Loans And Allowance For Credit Losses (Aging Information On Past Due And Accruing Loans) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	$ 16,276,066	$ 14,627,638
30 - 89 Days Past Due	71,769	80,100
90 Days Past Due and Still Accruing	24,584	19,859
Non-accrual loans	22,635	10,220
Total	16,395,054	14,737,817
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	6,858,217	5,565,449
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	932,022	899,377
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,941,163	2,833,554
Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,690,542	2,354,760
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	1,966,707	1,964,145
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	334,627	349,251
Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	666,597	764,977
Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	5,179	6,304
Commercial Portfolio Segment [Member] | Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Current or Less than 30 Days Past Due	6,828,267	5,545,104
30 - 89 Days Past Due	10,429	12,064
90 Days Past Due and Still Accruing	487	792
Non-accrual loans	19,034	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	931,697	882,826
30 - 89 Days Past Due	216	13,046
90 Days Past Due and Still Accruing	108	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	2,934,625	2,830,494
30 - 89 Days Past Due	4,617	2,030
90 Days Past Due and Still Accruing	0	0
Non-accrual loans	1,921	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	2,648,795	2,345,243
30 - 89 Days Past Due	27,531	6,129
90 Days Past Due and Still Accruing	12,537	1,689
Non-accrual loans	1,679	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	1,941,697	1,928,082
30 - 89 Days Past Due	22,576	34,053
90 Days Past Due and Still Accruing	2,434	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	332,916	347,258
30 - 89 Days Past Due	1,098	1,743
90 Days Past Due and Still Accruing	613	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	653,016	742,659
30 - 89 Days Past Due	5,176	10,703
90 Days Past Due and Still Accruing	8,405	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	5,053	5,972
30 - 89 Days Past Due	126	332
90 Days Past Due and Still Accruing	0	0
Non-accrual loans	$ 0	$ 0