Loans And Allowance For Credit Losses (Credit Quality Indicators Commercial Loan Portfolio) (Details) - Commercial Portfolio Segment [Member] $ in Thousands	Sep. 30, 2020 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	$ 3,664,618
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	2,192,679
Financing Receivable, Originated Two Years before Latest Fiscal Year	1,124,621
Financing Receivable, Originated Three Years before Latest Fiscal Year	785,315
Financing Receivable, Originated Four Years before Latest Fiscal Year	588,914
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	601,503
Financing Receivable, Revolving	1,728,684
Financing Receivable, before Allowance for Credit Loss, Total	10,686,334
Business [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	2,460,120
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	1,152,417
Financing Receivable, Originated Two Years before Latest Fiscal Year	540,702
Financing Receivable, Originated Three Years before Latest Fiscal Year	360,401
Financing Receivable, Originated Four Years before Latest Fiscal Year	196,498
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	327,248
Financing Receivable, Revolving	1,646,027
Financing Receivable, before Allowance for Credit Loss, Total	6,683,413
Real Estate - Construction And Land [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	408,820
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	323,632
Financing Receivable, Originated Two Years before Latest Fiscal Year	142,306
Financing Receivable, Originated Three Years before Latest Fiscal Year	76,764
Financing Receivable, Originated Four Years before Latest Fiscal Year	24,660
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	682
Financing Receivable, Revolving	32,865
Financing Receivable, before Allowance for Credit Loss, Total	1,009,729
Real Estate - Business [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	795,678
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	716,630
Financing Receivable, Originated Two Years before Latest Fiscal Year	441,613
Financing Receivable, Originated Three Years before Latest Fiscal Year	348,150
Financing Receivable, Originated Four Years before Latest Fiscal Year	367,756
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	273,573
Financing Receivable, Revolving	49,792
Financing Receivable, before Allowance for Credit Loss, Total	2,993,192
Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	3,514,978
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	2,119,417
Financing Receivable, Originated Two Years before Latest Fiscal Year	1,034,786
Financing Receivable, Originated Three Years before Latest Fiscal Year	689,299
Financing Receivable, Originated Four Years before Latest Fiscal Year	541,265
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	547,026
Financing Receivable, Revolving	1,614,600
Financing Receivable, before Allowance for Credit Loss, Total	10,061,371
Pass [Member] | Business [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	2,394,434
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	1,097,498
Financing Receivable, Originated Two Years before Latest Fiscal Year	518,966
Financing Receivable, Originated Three Years before Latest Fiscal Year	356,416
Financing Receivable, Originated Four Years before Latest Fiscal Year	186,992
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	307,681
Financing Receivable, Revolving	1,535,511
Financing Receivable, before Allowance for Credit Loss, Total	6,397,498
Pass [Member] | Real Estate - Construction And Land [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	407,465
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	323,632
Financing Receivable, Originated Two Years before Latest Fiscal Year	131,606
Financing Receivable, Originated Three Years before Latest Fiscal Year	49,040
Financing Receivable, Originated Four Years before Latest Fiscal Year	24,660
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	682
Financing Receivable, Revolving	32,865
Financing Receivable, before Allowance for Credit Loss, Total	969,950
Pass [Member] | Real Estate - Business [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	713,079
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	698,287
Financing Receivable, Originated Two Years before Latest Fiscal Year	384,214
Financing Receivable, Originated Three Years before Latest Fiscal Year	283,843
Financing Receivable, Originated Four Years before Latest Fiscal Year	329,613
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	238,663
Financing Receivable, Revolving	46,224
Financing Receivable, before Allowance for Credit Loss, Total	2,693,923
Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	54,280
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	40,477
Financing Receivable, Originated Two Years before Latest Fiscal Year	73,186
Financing Receivable, Originated Three Years before Latest Fiscal Year	22,618
Financing Receivable, Originated Four Years before Latest Fiscal Year	26,610
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	3,128
Financing Receivable, Revolving	63,975
Financing Receivable, before Allowance for Credit Loss, Total	284,274
Special Mention [Member] | Business [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	29,620
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	28,518
Financing Receivable, Originated Two Years before Latest Fiscal Year	17,532
Financing Receivable, Originated Three Years before Latest Fiscal Year	1,120
Financing Receivable, Originated Four Years before Latest Fiscal Year	5,773
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	1,843
Financing Receivable, Revolving	63,973
Financing Receivable, before Allowance for Credit Loss, Total	148,379
Special Mention [Member] | Real Estate - Construction And Land [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	0
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	0
Financing Receivable, Originated Two Years before Latest Fiscal Year	10,107
Financing Receivable, Originated Three Years before Latest Fiscal Year	14,555
Financing Receivable, Originated Four Years before Latest Fiscal Year	0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	0
Financing Receivable, Revolving	0
Financing Receivable, before Allowance for Credit Loss, Total	24,662
Special Mention [Member] | Real Estate - Business [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	24,660
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	11,959
Financing Receivable, Originated Two Years before Latest Fiscal Year	45,547
Financing Receivable, Originated Three Years before Latest Fiscal Year	6,943
Financing Receivable, Originated Four Years before Latest Fiscal Year	20,837
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	1,285
Financing Receivable, Revolving	2
Financing Receivable, before Allowance for Credit Loss, Total	111,233
Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	75,410
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	32,500
Financing Receivable, Originated Two Years before Latest Fiscal Year	13,960
Financing Receivable, Originated Three Years before Latest Fiscal Year	73,382
Financing Receivable, Originated Four Years before Latest Fiscal Year	20,914
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	47,351
Financing Receivable, Revolving	38,813
Financing Receivable, before Allowance for Credit Loss, Total	302,330
Substandard [Member] | Business [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	16,118
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	26,401
Financing Receivable, Originated Two Years before Latest Fiscal Year	2,139
Financing Receivable, Originated Three Years before Latest Fiscal Year	2,849
Financing Receivable, Originated Four Years before Latest Fiscal Year	3,608
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	13,879
Financing Receivable, Revolving	35,247
Financing Receivable, before Allowance for Credit Loss, Total	100,241
Substandard [Member] | Real Estate - Construction And Land [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	1,354
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	0
Financing Receivable, Originated Two Years before Latest Fiscal Year	593
Financing Receivable, Originated Three Years before Latest Fiscal Year	13,169
Financing Receivable, Originated Four Years before Latest Fiscal Year	0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	0
Financing Receivable, Revolving	0
Financing Receivable, before Allowance for Credit Loss, Total	15,116
Substandard [Member] | Real Estate - Business [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	57,938
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	6,099
Financing Receivable, Originated Two Years before Latest Fiscal Year	11,228
Financing Receivable, Originated Three Years before Latest Fiscal Year	57,364
Financing Receivable, Originated Four Years before Latest Fiscal Year	17,306
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	33,472
Financing Receivable, Revolving	3,566
Financing Receivable, before Allowance for Credit Loss, Total	186,973
Non-Accrual [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	19,950
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	285
Financing Receivable, Originated Two Years before Latest Fiscal Year	2,689
Financing Receivable, Originated Three Years before Latest Fiscal Year	16
Financing Receivable, Originated Four Years before Latest Fiscal Year	125
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	3,998
Financing Receivable, Revolving	11,296
Financing Receivable, before Allowance for Credit Loss, Total	38,359
Non-Accrual [Member] | Business [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	19,948
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	0
Financing Receivable, Originated Two Years before Latest Fiscal Year	2,065
Financing Receivable, Originated Three Years before Latest Fiscal Year	16
Financing Receivable, Originated Four Years before Latest Fiscal Year	125
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	3,845
Financing Receivable, Revolving	11,296
Financing Receivable, before Allowance for Credit Loss, Total	37,295
Non-Accrual [Member] | Real Estate - Construction And Land [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	1
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	0
Financing Receivable, Originated Two Years before Latest Fiscal Year	0
Financing Receivable, Originated Three Years before Latest Fiscal Year	0
Financing Receivable, Originated Four Years before Latest Fiscal Year	0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	0
Financing Receivable, Revolving	0
Financing Receivable, before Allowance for Credit Loss, Total	1
Non-Accrual [Member] | Real Estate - Business [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated in Current Fiscal Year	1
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	285
Financing Receivable, Originated Two Years before Latest Fiscal Year	624
Financing Receivable, Originated Three Years before Latest Fiscal Year	0
Financing Receivable, Originated Four Years before Latest Fiscal Year	0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	153
Financing Receivable, Revolving	0
Financing Receivable, before Allowance for Credit Loss, Total	$ 1,063