Loans and Leases (Composition of the Loans and Leases Outstanding By Credit Quality Indicator) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	$ 187,774	$ 245,485
Current loans	32,501,878	32,546,490
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	22,490,907	22,558,060
Commercial | Commercial and industrial and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	5,067,163	5,013,644
Commercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	1,183,929	985,424
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	9,802,239	9,771,033
Consumer | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	376,492	348,123
Non-PCI Loans | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans		67,117
Current loans		22,490,943
Non-PCI Loans | Commercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	26,088	25,071
Current loans	11,499,982	11,139,941
Non-PCI Loans | Commercial | Non-owner occupied commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	12,368	18,343
Current loans	3,002,961	2,969,346
Non-PCI Loans | Commercial | Commercial and industrial and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	22,398	20,617
Current loans	5,044,765	4,993,027
Non-PCI Loans | Commercial | Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	65,245	0
Current loans	22,425,662	2,406,291
Non-PCI Loans | Commercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	4,391	3,086
Current loans	1,179,538	982,338
Non-PCI Loans | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	76,026	122,944
Current loans	9,726,213	9,648,089
Non-PCI Loans | Consumer | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	880	1,339
Current loans	375,612	346,784
Non-PCI Loans | Consumer | Consumer other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	5,251	6,579
Current loans	595,864	546,389
PCD Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	46,503	55,424
Current loans	350,003	407,458
30 to 59 Days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	74,991	121,499
30 to 59 Days past due | Non-PCI Loans | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans		36,615
30 to 59 Days past due | Non-PCI Loans | Commercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	11,258	8,757
30 to 59 Days past due | Non-PCI Loans | Commercial | Non-owner occupied commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	5,356	12,370
30 to 59 Days past due | Non-PCI Loans | Commercial | Commercial and industrial and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	11,809	14,532
30 to 59 Days past due | Non-PCI Loans | Commercial | Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	30,472	0
30 to 59 Days past due | Non-PCI Loans | Commercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	2,049	956
30 to 59 Days past due | Non-PCI Loans | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	31,847	66,562
30 to 59 Days past due | Non-PCI Loans | Consumer | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	684	932
30 to 59 Days past due | Non-PCI Loans | Consumer | Consumer other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	3,089	3,610
30 to 59 Days past due | PCD Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	12,672	18,322
60 to 89 Days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	25,767	26,043
60 to 89 Days past due | Non-PCI Loans | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans		5,601
60 to 89 Days past due | Non-PCI Loans | Commercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	4,071	2,232
60 to 89 Days past due | Non-PCI Loans | Commercial | Non-owner occupied commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	3,659	0
60 to 89 Days past due | Non-PCI Loans | Commercial | Commercial and industrial and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	3,370	2,842
60 to 89 Days past due | Non-PCI Loans | Commercial | Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	11,100	0
60 to 89 Days past due | Non-PCI Loans | Commercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	0	527
60 to 89 Days past due | Non-PCI Loans | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	9,949	14,366
60 to 89 Days past due | Non-PCI Loans | Consumer | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	69	77
60 to 89 Days past due | Non-PCI Loans | Consumer | Consumer other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	1,020	1,464
60 to 89 Days past due | PCD Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	4,718	6,076
90 Days or greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	87,016	97,943
90 Days or greater | Non-PCI Loans | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans		24,901
90 Days or greater | Non-PCI Loans | Commercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	10,759	14,082
90 Days or greater | Non-PCI Loans | Commercial | Non-owner occupied commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	3,353	5,973
90 Days or greater | Non-PCI Loans | Commercial | Commercial and industrial and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	7,219	3,243
90 Days or greater | Non-PCI Loans | Commercial | Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	23,673	0
90 Days or greater | Non-PCI Loans | Commercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	2,342	1,603
90 Days or greater | Non-PCI Loans | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	34,230	42,016
90 Days or greater | Non-PCI Loans | Consumer | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	127	330
90 Days or greater | Non-PCI Loans | Consumer | Consumer other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	1,142	1,505
90 Days or greater | PCD Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	$ 29,113	$ 31,026