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Allowance for Credit Losses (Aging By Loan Class) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	$ 5,629	$ 6,132
Loans	7,531,773	7,430,603
Current
Financing receivable recorded investment
Loans	7,448,744	7,412,585
Total Past Due
Financing receivable recorded investment
Loans	83,029	18,018
30 to 59 Days
Financing receivable recorded investment
Loans	20,523	8,552
60 to 89 Days
Financing receivable recorded investment
Loans	6,234	2,251
90 Days or Greater
Financing receivable recorded investment
Loans	56,272	7,215
Commercial, financial and agricultural
Financing receivable recorded investment
Loans	4,370,745	4,373,373
Commercial, financial and agricultural | Domestic | Commercial.
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	121	59
Loans	1,498,102	1,498,754
Commercial, financial and agricultural | Domestic | Commercial. | Current
Financing receivable recorded investment
Loans	1,465,174	1,495,750
Commercial, financial and agricultural | Domestic | Commercial. | Total Past Due
Financing receivable recorded investment
Loans	32,928	3,004
Commercial, financial and agricultural | Domestic | Commercial. | 30 to 59 Days
Financing receivable recorded investment
Loans	2,162	1,732
Commercial, financial and agricultural | Domestic | Commercial. | 60 to 89 Days
Financing receivable recorded investment
Loans	217	258
Commercial, financial and agricultural | Domestic | Commercial. | 90 Days or Greater
Financing receivable recorded investment
Loans	30,549	1,014
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial
Financing receivable recorded investment
Loans	2,563,099	2,568,118
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Current
Financing receivable recorded investment
Loans	2,557,940	2,566,257
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Total Past Due
Financing receivable recorded investment
Loans	5,159	1,861
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | 30 to 59 Days
Financing receivable recorded investment
Loans	594	1,744
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | 60 to 89 Days
Financing receivable recorded investment
Loans	4,565	117
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily
Financing receivable recorded investment
Loans	309,544	306,501
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Current
Financing receivable recorded investment
Loans	309,311	306,501
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Total Past Due
Financing receivable recorded investment
Loans	233
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | 30 to 59 Days
Financing receivable recorded investment
Loans	233
Obligations of states and political subdivisions
Financing receivable recorded investment
Loans	2,081,138	1,989,669
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development
Financing receivable recorded investment
Loans	2,081,138	1,989,669
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Current
Financing receivable recorded investment
Loans	2,046,914	1,988,539
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Total Past Due
Financing receivable recorded investment
Loans	34,224	1,130
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | 30 to 59 Days
Financing receivable recorded investment
Loans	14,242	1,130
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | 90 Days or Greater
Financing receivable recorded investment
Loans	19,982
Real estate - mortgage
Financing receivable recorded investment
Loans	858,909	865,994
Real estate - mortgage | Domestic | Residential: first lien
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	2,864	4,061
Loans	419,555	425,724
Real estate - mortgage | Domestic | Residential: first lien | Current
Financing receivable recorded investment
Loans	414,116	418,444
Real estate - mortgage | Domestic | Residential: first lien | Total Past Due
Financing receivable recorded investment
Loans	5,439	7,280
Real estate - mortgage | Domestic | Residential: first lien | 30 to 59 Days
Financing receivable recorded investment
Loans	1,189	2,023
Real estate - mortgage | Domestic | Residential: first lien | 60 to 89 Days
Financing receivable recorded investment
Loans	1,153	1,068
Real estate - mortgage | Domestic | Residential: first lien | 90 Days or Greater
Financing receivable recorded investment
Loans	3,097	4,189
Real estate - mortgage | Domestic | Residential Junior Lien
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	2,051	1,717
Loans	439,354	440,270
Real estate - mortgage | Domestic | Residential Junior Lien | Current
Financing receivable recorded investment
Loans	435,810	436,857
Real estate - mortgage | Domestic | Residential Junior Lien | Total Past Due
Financing receivable recorded investment
Loans	3,544	3,413
Real estate - mortgage | Domestic | Residential Junior Lien | 30 to 59 Days
Financing receivable recorded investment
Loans	1,235	925
Real estate - mortgage | Domestic | Residential Junior Lien | 60 to 89 Days
Financing receivable recorded investment
Loans	258	771
Real estate - mortgage | Domestic | Residential Junior Lien | 90 Days or Greater
Financing receivable recorded investment
Loans	2,051	1,717
Consumer
Financing receivable recorded investment
Loans	43,390	41,592
Consumer | Domestic
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	12	7
Loans	43,390	41,592
Consumer | Domestic | Current
Financing receivable recorded investment
Loans	43,078	41,290
Consumer | Domestic | Total Past Due
Financing receivable recorded investment
Loans	312	302
Consumer | Domestic | 30 to 59 Days
Financing receivable recorded investment
Loans	270	281
Consumer | Domestic | 60 to 89 Days
Financing receivable recorded investment
Loans	30	14
Consumer | Domestic | 90 Days or Greater
Financing receivable recorded investment
Loans	12	7
Foreign.
Financing receivable recorded investment
Loans	177,591	159,975
Foreign. | Foreign
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	581	288
Loans	177,591	159,975
Foreign. | Foreign | Current
Financing receivable recorded investment
Loans	176,401	158,947
Foreign. | Foreign | Total Past Due
Financing receivable recorded investment
Loans	1,190	1,028
Foreign. | Foreign | 30 to 59 Days
Financing receivable recorded investment
Loans	598	717
Foreign. | Foreign | 60 to 89 Days
Financing receivable recorded investment
Loans	11	23
Foreign. | Foreign | 90 Days or Greater
Financing receivable recorded investment
Loans	$ 581	$ 288

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