Loans and Allowance for Credit Losses (Disaggregation of Credit Quality Disclosures) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Total Commercial [Member]
Accounts Notes And Loans Receivable [Line Items]
Term Loans, Amortized Cost Basis by Origination Year, 2021	$ 5,076,311	$ 5,867,582
Term Loans, Amortized Cost Basis by Origination Year, 2020	3,073,804	2,977,170
Term Loans, Amortized Cost Basis by Origination Year, 2019	2,114,506	1,832,860
Term Loans, Amortized Cost Basis by Origination Year, 2018	1,285,226	1,500,272
Term Loans, Amortized Cost Basis by Origination Year, 2017	1,003,833	1,062,429
Term Loans, Amortized Cost Basis by Origination Year, Prior	1,385,473	1,357,011
Revolving Loans	3,084,875	2,543,475
Revolving Loans Converted to Term Loans	102,974	126,625
Notes Receivable Gross	17,127,002	17,267,424
Total Commercial [Member] | Pass [Member]
Accounts Notes And Loans Receivable [Line Items]
Term Loans, Amortized Cost Basis by Origination Year, 2021	4,946,459	5,673,370
Term Loans, Amortized Cost Basis by Origination Year, 2020	3,008,160	2,819,696
Term Loans, Amortized Cost Basis by Origination Year, 2019	2,035,849	1,740,784
Term Loans, Amortized Cost Basis by Origination Year, 2018	1,212,306	1,391,140
Term Loans, Amortized Cost Basis by Origination Year, 2017	937,639	960,094
Term Loans, Amortized Cost Basis by Origination Year, Prior	1,296,382	1,231,913
Revolving Loans	3,002,064	2,420,058
Revolving Loans Converted to Term Loans	80,535	95,847
Notes Receivable Gross	16,519,394	16,332,902
Total Commercial [Member] | Pass-Watch [Member]
Accounts Notes And Loans Receivable [Line Items]
Term Loans, Amortized Cost Basis by Origination Year, 2021	68,421	115,555
Term Loans, Amortized Cost Basis by Origination Year, 2020	19,467	96,473
Term Loans, Amortized Cost Basis by Origination Year, 2019	31,598	50,475
Term Loans, Amortized Cost Basis by Origination Year, 2018	45,846	42,877
Term Loans, Amortized Cost Basis by Origination Year, 2017	27,188	58,331
Term Loans, Amortized Cost Basis by Origination Year, Prior	69,310	84,363
Revolving Loans	52,850	74,629
Revolving Loans Converted to Term Loans	5,714	19,182
Notes Receivable Gross	320,394	541,885
Total Commercial [Member] | Special Mention [Member]
Accounts Notes And Loans Receivable [Line Items]
Term Loans, Amortized Cost Basis by Origination Year, 2021	17,536	3,196
Term Loans, Amortized Cost Basis by Origination Year, 2020	2,683	27,157
Term Loans, Amortized Cost Basis by Origination Year, 2019	10,296	21,074
Term Loans, Amortized Cost Basis by Origination Year, 2018	12,410	30,872
Term Loans, Amortized Cost Basis by Origination Year, 2017	10,669	28,933
Term Loans, Amortized Cost Basis by Origination Year, Prior	3,656	4,146
Revolving Loans	9,603	18,626
Revolving Loans Converted to Term Loans	6,243	3,588
Notes Receivable Gross	73,096	137,592
Total Commercial [Member] | Substandard [Member]
Accounts Notes And Loans Receivable [Line Items]
Term Loans, Amortized Cost Basis by Origination Year, 2021	43,895	75,461
Term Loans, Amortized Cost Basis by Origination Year, 2020	43,494	33,844
Term Loans, Amortized Cost Basis by Origination Year, 2019	36,763	20,527
Term Loans, Amortized Cost Basis by Origination Year, 2018	14,664	35,383
Term Loans, Amortized Cost Basis by Origination Year, 2017	28,337	15,071
Term Loans, Amortized Cost Basis by Origination Year, Prior	16,125	36,589
Revolving Loans	20,358	30,162
Revolving Loans Converted to Term Loans	10,482	8,008
Notes Receivable Gross	214,118	255,045
Residential Mortgage and Consumer [Member]
Accounts Notes And Loans Receivable [Line Items]
Term Loans, Amortized Cost Basis by Origination Year, 2021	581,378	440,297
Term Loans, Amortized Cost Basis by Origination Year, 2020	468,448	507,905
Term Loans, Amortized Cost Basis by Origination Year, 2019	357,851	443,399
Term Loans, Amortized Cost Basis by Origination Year, 2018	227,959	568,727
Term Loans, Amortized Cost Basis by Origination Year, 2017	325,063	504,999
Term Loans, Amortized Cost Basis by Origination Year, Prior	916,726	852,067
Revolving Loans	1,121,893	1,194,427
Revolving Loans Converted to Term Loans	7,962	10,686
Notes Receivable Gross	4,007,280	4,522,507
Residential Mortgage and Consumer [Member] | Performing [Member]
Accounts Notes And Loans Receivable [Line Items]
Term Loans, Amortized Cost Basis by Origination Year, 2021	580,813	438,831
Term Loans, Amortized Cost Basis by Origination Year, 2020	467,497	504,124
Term Loans, Amortized Cost Basis by Origination Year, 2019	355,833	437,518
Term Loans, Amortized Cost Basis by Origination Year, 2018	223,494	560,347
Term Loans, Amortized Cost Basis by Origination Year, 2017	320,344	501,018
Term Loans, Amortized Cost Basis by Origination Year, Prior	892,361	816,567
Revolving Loans	1,120,461	1,190,775
Revolving Loans Converted to Term Loans	5,995	6,127
Notes Receivable Gross	3,966,798	4,455,307
Residential Mortgage and Consumer [Member] | Nonperforming [Member]
Accounts Notes And Loans Receivable [Line Items]
Term Loans, Amortized Cost Basis by Origination Year, 2021	565	1,466
Term Loans, Amortized Cost Basis by Origination Year, 2020	951	3,781
Term Loans, Amortized Cost Basis by Origination Year, 2019	2,018	5,881
Term Loans, Amortized Cost Basis by Origination Year, 2018	4,465	8,380
Term Loans, Amortized Cost Basis by Origination Year, 2017	4,719	3,981
Term Loans, Amortized Cost Basis by Origination Year, Prior	24,365	35,500
Revolving Loans	1,432	3,652
Revolving Loans Converted to Term Loans	1,967	4,559
Notes Receivable Gross	$ 40,482	$ 67,200