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Allowance for Credit Losses - Aging By Loan Class (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	$ 4,768	$ 5,597
Loans	8,112,481	8,058,961
Current
Financing receivable recorded investment
Loans	8,042,936	7,995,156
Total Past Due
Financing receivable recorded investment
Loans	69,545	63,805
30 to 59 Days
Financing receivable recorded investment
Loans	37,047	12,872
60 to 89 Days
Financing receivable recorded investment
Loans	13,240	5,195
90 Days or Greater
Financing receivable recorded investment
Loans	19,258	45,738
Commercial, financial and agricultural
Financing receivable recorded investment
Loans	4,715,769	4,802,622
Commercial, financial and agricultural | Domestic | Commercial.
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	462	539
Loans	1,581,207	1,628,230
Commercial, financial and agricultural | Domestic | Commercial. | Current
Financing receivable recorded investment
Loans	1,573,026	1,594,022
Commercial, financial and agricultural | Domestic | Commercial. | Total Past Due
Financing receivable recorded investment
Loans	8,181	34,208
Commercial, financial and agricultural | Domestic | Commercial. | 30 to 59 Days
Financing receivable recorded investment
Loans	3,234	2,387
Commercial, financial and agricultural | Domestic | Commercial. | 60 to 89 Days
Financing receivable recorded investment
Loans	334	1,583
Commercial, financial and agricultural | Domestic | Commercial. | 90 Days or Greater
Financing receivable recorded investment
Loans	4,613	30,238
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	59	4
Loans	2,810,956	2,793,553
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Current
Financing receivable recorded investment
Loans	2,808,236	2,791,665
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Total Past Due
Financing receivable recorded investment
Loans	2,720	1,888
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | 30 to 59 Days
Financing receivable recorded investment
Loans	1,260	1,424
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | 60 to 89 Days
Financing receivable recorded investment
Loans	1,401	371
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | 90 Days or Greater
Financing receivable recorded investment
Loans	59	93
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily
Financing receivable recorded investment
Loans	323,606	380,839
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Current
Financing receivable recorded investment
Loans	298,542	380,140
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Total Past Due
Financing receivable recorded investment
Loans	25,064	699
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | 30 to 59 Days
Financing receivable recorded investment
Loans	25,064	369
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | 60 to 89 Days
Financing receivable recorded investment
Loans		330
Obligations of states and political subdivisions
Financing receivable recorded investment
Loans	2,219,432	2,091,622
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development
Financing receivable recorded investment
Loans	2,219,432	2,091,622
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Current
Financing receivable recorded investment
Loans	2,198,636	2,077,917
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Total Past Due
Financing receivable recorded investment
Loans	20,796	13,705
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | 30 to 59 Days
Financing receivable recorded investment
Loans	1,317	3,460
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | 60 to 89 Days
Financing receivable recorded investment
Loans	9,230
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | 90 Days or Greater
Financing receivable recorded investment
Loans	10,249	10,245
Real estate - mortgage
Financing receivable recorded investment
Loans	954,469	938,901
Real estate - mortgage | Domestic | Residential: first lien
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	2,296	2,437
Loans	486,788	478,032
Real estate - mortgage | Domestic | Residential: first lien | Current
Financing receivable recorded investment
Loans	479,679	472,236
Real estate - mortgage | Domestic | Residential: first lien | Total Past Due
Financing receivable recorded investment
Loans	7,109	5,796
Real estate - mortgage | Domestic | Residential: first lien | 30 to 59 Days
Financing receivable recorded investment
Loans	3,470	1,812
Real estate - mortgage | Domestic | Residential: first lien | 60 to 89 Days
Financing receivable recorded investment
Loans	1,253	1,439
Real estate - mortgage | Domestic | Residential: first lien | 90 Days or Greater
Financing receivable recorded investment
Loans	2,386	2,545
Real estate - mortgage | Domestic | Residential Junior Lien
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	1,685	1,701
Loans	467,681	460,869
Real estate - mortgage | Domestic | Residential Junior Lien | Current
Financing receivable recorded investment
Loans	463,653	457,282
Real estate - mortgage | Domestic | Residential Junior Lien | Total Past Due
Financing receivable recorded investment
Loans	4,028	3,587
Real estate - mortgage | Domestic | Residential Junior Lien | 30 to 59 Days
Financing receivable recorded investment
Loans	1,868	1,273
Real estate - mortgage | Domestic | Residential Junior Lien | 60 to 89 Days
Financing receivable recorded investment
Loans	475	613
Real estate - mortgage | Domestic | Residential Junior Lien | 90 Days or Greater
Financing receivable recorded investment
Loans	1,685	1,701
Consumer
Financing receivable recorded investment
Loans	46,358	45,121
Consumer | Domestic
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	14	27
Loans	46,358	45,121
Consumer | Domestic | Current
Financing receivable recorded investment
Loans	46,016	44,820
Consumer | Domestic | Total Past Due
Financing receivable recorded investment
Loans	342	301
Consumer | Domestic | 30 to 59 Days
Financing receivable recorded investment
Loans	304	263
Consumer | Domestic | 60 to 89 Days
Financing receivable recorded investment
Loans	24	11
Consumer | Domestic | 90 Days or Greater
Financing receivable recorded investment
Loans	14	27
Foreign.
Financing receivable recorded investment
Loans	176,453	180,695
Foreign. | Foreign
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	252	889
Loans	176,453	180,695
Foreign. | Foreign | Current
Financing receivable recorded investment
Loans	175,148	177,074
Foreign. | Foreign | Total Past Due
Financing receivable recorded investment
Loans	1,305	3,621
Foreign. | Foreign | 30 to 59 Days
Financing receivable recorded investment
Loans	530	1,884
Foreign. | Foreign | 60 to 89 Days
Financing receivable recorded investment
Loans	523	848
Foreign. | Foreign | 90 Days or Greater
Financing receivable recorded investment
Loans	$ 252	$ 889

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
-Topic 326
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

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+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 80
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479294/326-20-55-80

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