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Allowance for Credit Losses (Aging By Loan Class) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	$ 4,680	$ 6,132
Loans	7,896,899	7,430,603
Current
Financing receivable recorded investment
Loans	7,829,476	7,412,585
Total Past Due
Financing receivable recorded investment
Loans	67,423	18,018
30 to 59 Days
Financing receivable recorded investment
Loans	18,762	8,552
60 to 89 Days
Financing receivable recorded investment
Loans	2,622	2,251
90 Days or Greater
Financing receivable recorded investment
Loans	46,039	7,215
Commercial, financial and agricultural
Financing receivable recorded investment
Loans	4,637,170	4,373,373
Commercial, financial and agricultural | Domestic | Commercial.
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	89	59
Loans	1,556,827	1,498,754
Commercial, financial and agricultural | Domestic | Commercial. | Current
Financing receivable recorded investment
Loans	1,522,660	1,495,750
Commercial, financial and agricultural | Domestic | Commercial. | Total Past Due
Financing receivable recorded investment
Loans	34,167	3,004
Commercial, financial and agricultural | Domestic | Commercial. | 30 to 59 Days
Financing receivable recorded investment
Loans	2,529	1,732
Commercial, financial and agricultural | Domestic | Commercial. | 60 to 89 Days
Financing receivable recorded investment
Loans	354	258
Commercial, financial and agricultural | Domestic | Commercial. | 90 Days or Greater
Financing receivable recorded investment
Loans	31,284	1,014
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial
Financing receivable recorded investment
Loans	2,746,673	2,568,118
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Current
Financing receivable recorded investment
Loans	2,745,206	2,566,257
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Total Past Due
Financing receivable recorded investment
Loans	1,467	1,861
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | 30 to 59 Days
Financing receivable recorded investment
Loans	1,329	1,744
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | 60 to 89 Days
Financing receivable recorded investment
Loans	138	117
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily
Financing receivable recorded investment
Loans	333,670	306,501
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Current
Financing receivable recorded investment
Loans	333,235	306,501
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Total Past Due
Financing receivable recorded investment
Loans	435
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | 30 to 59 Days
Financing receivable recorded investment
Loans	435
Obligations of states and political subdivisions
Financing receivable recorded investment
Loans	2,126,302	1,989,669
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development
Financing receivable recorded investment
Loans	2,126,302	1,989,669
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Current
Financing receivable recorded investment
Loans	2,106,809	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	19,493	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	9,292	1,130
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | 60 to 89 Days
Financing receivable recorded investment
Loans	200
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | 90 Days or Greater
Financing receivable recorded investment
Loans	10,001
Real estate - mortgage
Financing receivable recorded investment
Loans	907,615	865,994
Real estate - mortgage | Domestic | Residential: first lien
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	2,160	4,061
Loans	456,397	425,724
Real estate - mortgage | Domestic | Residential: first lien | Current
Financing receivable recorded investment
Loans	450,099	418,444
Real estate - mortgage | Domestic | Residential: first lien | Total Past Due
Financing receivable recorded investment
Loans	6,298	7,280
Real estate - mortgage | Domestic | Residential: first lien | 30 to 59 Days
Financing receivable recorded investment
Loans	2,764	2,023
Real estate - mortgage | Domestic | Residential: first lien | 60 to 89 Days
Financing receivable recorded investment
Loans	1,211	1,068
Real estate - mortgage | Domestic | Residential: first lien | 90 Days or Greater
Financing receivable recorded investment
Loans	2,323	4,189
Real estate - mortgage | Domestic | Residential Junior Lien
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	1,805	1,717
Loans	451,218	440,270
Real estate - mortgage | Domestic | Residential Junior Lien | Current
Financing receivable recorded investment
Loans	447,435	436,857
Real estate - mortgage | Domestic | Residential Junior Lien | Total Past Due
Financing receivable recorded investment
Loans	3,783	3,413
Real estate - mortgage | Domestic | Residential Junior Lien | 30 to 59 Days
Financing receivable recorded investment
Loans	1,330	925
Real estate - mortgage | Domestic | Residential Junior Lien | 60 to 89 Days
Financing receivable recorded investment
Loans	648	771
Real estate - mortgage | Domestic | Residential Junior Lien | 90 Days or Greater
Financing receivable recorded investment
Loans	1,805	1,717
Consumer
Financing receivable recorded investment
Loans	44,767	41,592
Consumer | Domestic
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	80	7
Loans	44,767	41,592
Consumer | Domestic | Current
Financing receivable recorded investment
Loans	44,274	41,290
Consumer | Domestic | Total Past Due
Financing receivable recorded investment
Loans	493	302
Consumer | Domestic | 30 to 59 Days
Financing receivable recorded investment
Loans	354	281
Consumer | Domestic | 60 to 89 Days
Financing receivable recorded investment
Loans	59	14
Consumer | Domestic | 90 Days or Greater
Financing receivable recorded investment
Loans	80	7
Foreign.
Financing receivable recorded investment
Loans	181,045	159,975
Foreign. | Foreign
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	546	288
Loans	181,045	159,975
Foreign. | Foreign | Current
Financing receivable recorded investment
Loans	179,758	158,947
Foreign. | Foreign | Total Past Due
Financing receivable recorded investment
Loans	1,287	1,028
Foreign. | Foreign | 30 to 59 Days
Financing receivable recorded investment
Loans	729	717
Foreign. | Foreign | 60 to 89 Days
Financing receivable recorded investment
Loans	12	23
Foreign. | Foreign | 90 Days or Greater
Financing receivable recorded investment
Loans	$ 546	$ 288

X

- Definition

Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479344/326-20-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
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