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Allowance for Credit Losses - Aging By Loan Class (Details) $ in Thousands	Jun. 30, 2024 USD ($) loan	Dec. 31, 2023 USD ($)
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	$ 5,686	$ 5,597
Loans	8,267,827	8,058,961
Current
Financing receivable recorded investment
Loans	8,164,358	7,995,156
Total Past Due
Financing receivable recorded investment
Loans	103,469	63,805
30 to 59 Days
Financing receivable recorded investment
Loans	57,623	12,872
60 to 89 Days
Financing receivable recorded investment
Loans	3,983	5,195
90 Days or Greater
Financing receivable recorded investment
Loans	$ 41,863	45,738
Commercial Real Estate: other construction and land development
Financing receivable recorded investment
Number of loans placed on non-accrual | loan	3
Commercial real estate: multifamily
Financing receivable recorded investment
Number of loans placed on non-accrual | loan	2
Commercial, financial and agricultural
Financing receivable recorded investment
Loans	$ 4,769,703	4,802,622
Commercial, financial and agricultural | Domestic | Commercial.
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	639	539
Loans	1,585,177	1,628,230
Commercial, financial and agricultural | Domestic | Commercial. | Current
Financing receivable recorded investment
Loans	1,577,014	1,594,022
Commercial, financial and agricultural | Domestic | Commercial. | Total Past Due
Financing receivable recorded investment
Loans	8,163	34,208
Commercial, financial and agricultural | Domestic | Commercial. | 30 to 59 Days
Financing receivable recorded investment
Loans	4,558	2,387
Commercial, financial and agricultural | Domestic | Commercial. | 60 to 89 Days
Financing receivable recorded investment
Loans	1,892	1,583
Commercial, financial and agricultural | Domestic | Commercial. | 90 Days or Greater
Financing receivable recorded investment
Loans	1,713	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	168	4
Loans	2,867,392	2,793,553
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Current
Financing receivable recorded investment
Loans	2,861,696	2,791,665
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Total Past Due
Financing receivable recorded investment
Loans	5,696	1,888
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | 30 to 59 Days
Financing receivable recorded investment
Loans	5,474	1,424
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | 60 to 89 Days
Financing receivable recorded investment
Loans	54	371
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | 90 Days or Greater
Financing receivable recorded investment
Loans	168	93
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	470
Loans	317,134	380,839
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Current
Financing receivable recorded investment
Loans	277,928	380,140
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Total Past Due
Financing receivable recorded investment
Loans	39,206	699
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | 30 to 59 Days
Financing receivable recorded investment
Loans	13,672	369
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | 60 to 89 Days
Financing receivable recorded investment
Loans		330
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | 90 Days or Greater
Financing receivable recorded investment
Loans	25,534
Obligations of states and political subdivisions
Financing receivable recorded investment
Loans	2,303,690	2,091,622
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development
Financing receivable recorded investment
Loans	2,303,690	2,091,622
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Current
Financing receivable recorded investment
Loans	2,268,924	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	34,766	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	24,807	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	7
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | 90 Days or Greater
Financing receivable recorded investment
Loans	9,952	10,245
Real estate - mortgage
Financing receivable recorded investment
Loans	967,792	938,901
Real estate - mortgage | Domestic | Residential: first lien
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	2,556	2,437
Loans	498,650	478,032
Real estate - mortgage | Domestic | Residential: first lien | Current
Financing receivable recorded investment
Loans	490,913	472,236
Real estate - mortgage | Domestic | Residential: first lien | Total Past Due
Financing receivable recorded investment
Loans	7,737	5,796
Real estate - mortgage | Domestic | Residential: first lien | 30 to 59 Days
Financing receivable recorded investment
Loans	4,082	1,812
Real estate - mortgage | Domestic | Residential: first lien | 60 to 89 Days
Financing receivable recorded investment
Loans	1,012	1,439
Real estate - mortgage | Domestic | Residential: first lien | 90 Days or Greater
Financing receivable recorded investment
Loans	2,643	2,545
Real estate - mortgage | Domestic | Residential Junior Lien
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	1,828	1,701
Loans	469,142	460,869
Real estate - mortgage | Domestic | Residential Junior Lien | Current
Financing receivable recorded investment
Loans	464,877	457,282
Real estate - mortgage | Domestic | Residential Junior Lien | Total Past Due
Financing receivable recorded investment
Loans	4,265	3,587
Real estate - mortgage | Domestic | Residential Junior Lien | 30 to 59 Days
Financing receivable recorded investment
Loans	1,557	1,273
Real estate - mortgage | Domestic | Residential Junior Lien | 60 to 89 Days
Financing receivable recorded investment
Loans	880	613
Real estate - mortgage | Domestic | Residential Junior Lien | 90 Days or Greater
Financing receivable recorded investment
Loans	1,828	1,701
Consumer
Financing receivable recorded investment
Loans	46,954	45,121
Consumer | Domestic
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	25	27
Loans	46,954	45,121
Consumer | Domestic | Current
Financing receivable recorded investment
Loans	46,803	44,820
Consumer | Domestic | Total Past Due
Financing receivable recorded investment
Loans	151	301
Consumer | Domestic | 30 to 59 Days
Financing receivable recorded investment
Loans	94	263
Consumer | Domestic | 60 to 89 Days
Financing receivable recorded investment
Loans	32	11
Consumer | Domestic | 90 Days or Greater
Financing receivable recorded investment
Loans	25	27
Foreign.
Financing receivable recorded investment
Loans	179,688	180,695
Foreign. | Foreign
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing		889
Loans	179,688	180,695
Foreign. | Foreign | Current
Financing receivable recorded investment
Loans	176,203	177,074
Foreign. | Foreign | Total Past Due
Financing receivable recorded investment
Loans	3,485	3,621
Foreign. | Foreign | 30 to 59 Days
Financing receivable recorded investment
Loans	3,379	1,884
Foreign. | Foreign | 60 to 89 Days
Financing receivable recorded investment
Loans	$ 106	848
Foreign. | Foreign | 90 Days or Greater
Financing receivable recorded investment
Loans		$ 889

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