Loans and Leases (Composition of the Loans and Leases Outstanding by Credit Quality Indicator) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	$ 32,371,522	$ 32,791,975
Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	32,232,138	32,546,490
30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	71,053	121,499
60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	16,462	26,043
90 days or greater
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	51,869	97,943
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	22,280,288	22,558,060
Consumer Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	9,753,610	9,771,033
Construction and land development | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	1,111,797	985,424
Construction and land development | Commercial | Pass
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	1,104,778	970,865
Construction and land development | Commercial | Special mention
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	498	12,162
Construction and land development | Commercial | Substandard
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	6,521	2,397
Construction and land development | Consumer Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	399,570	348,123
Construction and land development | Consumer Portfolio Segment | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	388	932
Construction and land development | Consumer Portfolio Segment | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	0	77
Construction and land development | Consumer Portfolio Segment | 90 days or greater
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	41	330
Commercial and industrial | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	5,710,652	5,013,644
Commercial and industrial | Commercial | Pass
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	5,541,997	4,846,634
Commercial and industrial | Commercial | Special mention
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	46,069	50,429
Commercial and industrial | Commercial | Substandard
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	50,538	60,249
Commercial and industrial | Commercial | Doubtful
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	1
Commercial and industrial | Commercial | Ungraded
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	72,047	56,332
Non-PCI Loans | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		22,558,060
Non-PCI Loans | Commercial | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		22,490,943
Non-PCI Loans | Commercial | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		36,615
Non-PCI Loans | Commercial | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		5,601
Non-PCI Loans | Commercial | 90 days or greater
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		24,901
Non-PCI Loans | Consumer Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	9,753,610	9,771,033
Non-PCI Loans | Consumer Portfolio Segment | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	9,690,703	9,648,089
Non-PCI Loans | Consumer Portfolio Segment | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	32,382	66,562
Non-PCI Loans | Consumer Portfolio Segment | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	9,299	14,366
Non-PCI Loans | Consumer Portfolio Segment | 90 days or greater
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	21,226	42,016
Non-PCI Loans | Construction and land development | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	1,111,797	985,424
Non-PCI Loans | Construction and land development | Commercial | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	1,109,242	982,338
Non-PCI Loans | Construction and land development | Commercial | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	456	956
Non-PCI Loans | Construction and land development | Commercial | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	0	527
Non-PCI Loans | Construction and land development | Commercial | 90 days or greater
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	2,099	1,603
Non-PCI Loans | Construction and land development | Consumer Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	399,570	348,123
Non-PCI Loans | Construction and land development | Consumer Portfolio Segment | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	399,141	346,784
Non-PCI Loans | Construction and land development | Consumer Portfolio Segment | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	388	932
Non-PCI Loans | Construction and land development | Consumer Portfolio Segment | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	0	77
Non-PCI Loans | Construction and land development | Consumer Portfolio Segment | 90 days or greater
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	41	330
Non-PCI Loans | Mortgage | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		11,165,012
Non-PCI Loans | Mortgage | Commercial | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		11,139,941
Non-PCI Loans | Mortgage | Commercial | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		8,757
Non-PCI Loans | Mortgage | Commercial | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		2,232
Non-PCI Loans | Mortgage | Commercial | 90 days or greater
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		14,082
Non-PCI Loans | Other commercial real estate | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		2,987,689
Non-PCI Loans | Other commercial real estate | Commercial | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		2,969,346
Non-PCI Loans | Other commercial real estate | Commercial | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		12,370
Non-PCI Loans | Other commercial real estate | Commercial | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		0
Non-PCI Loans | Other commercial real estate | Commercial | 90 days or greater
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		5,973
Non-PCI Loans | Commercial and industrial | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	5,710,652	5,013,644
Non-PCI Loans | Commercial and industrial | Commercial | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	5,692,791	4,993,027
Non-PCI Loans | Commercial and industrial | Commercial | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	7,909	14,532
Non-PCI Loans | Commercial and industrial | Commercial | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	3,714	2,842
Non-PCI Loans | Commercial and industrial | Commercial | 90 days or greater
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	6,238	3,243
Non-PCI Loans | Other | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	22,280,288	2,406,291
Non-PCI Loans | Other | Commercial | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	22,230,768	2,406,291
Non-PCI Loans | Other | Commercial | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	27,773	0
Non-PCI Loans | Other | Commercial | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	4,264	0
Non-PCI Loans | Other | Commercial | 90 days or greater
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	17,483	0
Non-PCI Loans | Consumer | Consumer Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		552,968
Non-PCI Loans | Consumer | Consumer Portfolio Segment | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		546,389
Non-PCI Loans | Consumer | Consumer Portfolio Segment | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		3,610
Non-PCI Loans | Consumer | Consumer Portfolio Segment | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		1,464
Non-PCI Loans | Consumer | Consumer Portfolio Segment | 90 days or greater
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases		1,505
PCD Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	337,624	462,882
PCD Loans | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	310,667	407,458
PCD Loans | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	10,898	18,322
PCD Loans | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	2,899	6,076
PCD Loans | 90 days or greater
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans and leases	$ 13,160	$ 31,026