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Allowance for Credit Losses - Portfolio Credit Quality (Details) $ in Thousands | 3 Months Ended | 12 Months Ended
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Mar. 31, 2024 USD ($) loan | Mar. 31, 2023 USD ($) | Dec. 31, 2023 USD ($)
Loan portfolio by credit quality indicator |  |  |
2024 | $ 759,708 |  |
2023 | 3,055,491 |  | $ 3,364,226
2022 | 1,735,632 |  | 1,928,023
2021 | 1,262,416 |  | 1,328,045
2020 | 522,243 |  | 609,341
2019/Prior | 776,991 |  | 295,840
Prior |  |  | 533,486
Total loans | 8,112,481 |  | 8,058,961
Current-period gross writeoffs |  |  |
Total | 27,824 | $ 2,033 |
Commercial, financial and agricultural |  |  |
Loan portfolio by credit quality indicator |  |  |
Total loans | $ 4,715,769 |  | 4,802,622
Commercial, financial and agricultural | Commercial. |  |  |
Current-period gross writeoffs |  |  |
Number of loans downgraded | loan | 1 |  |
Commercial, financial and agricultural | Domestic | Commercial. |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | $ 158,462 |  |
2023 | 704,883 |  | 811,918
2022 | 223,180 |  | 305,621
2021 | 351,953 |  | 364,498
2020 | 43,711 |  | 50,602
2019/Prior | 99,018 |  | 21,468
Prior |  |  | 74,123
Total loans | 1,581,207 |  | 1,628,230
Current-period gross writeoffs |  |  |
2023 | 2,114 |  | 7,053
2022 | 25,606 |  | 2,187
2021 | 19 |  | 155
2020 |  |  | 264
2019 |  |  | 2
Prior | 2 |  |
Prior |  |  | 3
Total | 27,741 | 1,971 | 9,664
Commercial, financial and agricultural | Domestic | Commercial. | Pass |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 158,276 |  |
2023 | 684,653 |  | 791,233
2022 | 216,434 |  | 272,919
2021 | 351,778 |  | 364,271
2020 | 43,711 |  | 50,602
2019/Prior | 99,017 |  | 21,468
Prior |  |  | 74,119
Total loans | 1,553,869 |  | 1,574,612
Commercial, financial and agricultural | Domestic | Commercial. | Special Review |  |  |
Loan portfolio by credit quality indicator |  |  |
2023 | 7,078 |  | 7,613
2022 | 1,604 |  | 1,800
2021 | 151 |  | 164
Total loans | 8,833 |  | 9,577
Commercial, financial and agricultural | Domestic | Commercial. | Watch List - Pass |  |  |
Loan portfolio by credit quality indicator |  |  |
2023 | 11,864 |  | 11,865
Total loans | 11,864 |  | 11,865
Commercial, financial and agricultural | Domestic | Commercial. | Watch List - Substandard |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 186 |  |
2023 | 985 |  | 1,180
2022 |  |  | 92
2021 | 24 |  | 28
2019/Prior | 1 |  |
Prior |  |  | 4
Total loans | 1,196 |  | 1,304
Commercial, financial and agricultural | Domestic | Commercial. | Watch List - Doubtful |  |  |
Loan portfolio by credit quality indicator |  |  |
2023 | 303 |  | 27
2022 | 5,142 |  | 30,810
2021 |  |  | 35
Total loans | 5,445 |  | 30,872
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 111,410 |  |
2023 | 988,251 |  | 1,040,592
2022 | 617,242 |  | 631,029
2021 | 417,805 |  | 419,048
2020 | 265,171 |  | 270,009
2019/Prior | 411,077 |  | 184,248
Prior |  |  | 248,627
Total loans | 2,810,956 |  | 2,793,553
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Pass |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 94,211 |  |
2023 | 858,865 |  | 888,878
2022 | 615,060 |  | 628,653
2021 | 414,257 |  | 415,458
2020 | 262,875 |  | 267,705
2019/Prior | 410,995 |  | 184,164
Prior |  |  | 248,626
Total loans | 2,656,263 |  | 2,633,484
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Special Review |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 520 |  |
2023 | 173 |  | 5,205
2021 |  |  | 3,357
Total loans | 693 |  | 8,562
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Watch List - Pass |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 16,679 |  |
2023 |  |  | 16,654
2022 |  |  | 87
2021 | 3,548 |  | 233
2019/Prior | 1 |  |
Total loans | 20,228 |  | 16,974
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Watch List - Substandard |  |  |
Loan portfolio by credit quality indicator |  |  |
2023 | 129,002 |  | 129,644
2022 | 2,182 |  | 2,201
2020 | 2,296 |  | 2,304
2019/Prior | 81 |  | 84
Prior |  |  | 1
Total loans | 133,561 |  | 134,234
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Watch List - Doubtful |  |  |
Loan portfolio by credit quality indicator |  |  |
2023 | 211 |  | 211
2022 |  |  | 88
Total loans | 211 |  | 299
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 69,744 |  |
2023 | 93,196 |  | 123,523
2022 | 93,670 |  | 94,647
2021 | 22,696 |  | 42,081
2020 | 9,675 |  | 73,652
2019/Prior | 34,625 |  | 10,743
Prior |  |  | 36,193
Total loans | 323,606 |  | 380,839
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Pass |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 69,744 |  |
2023 | 68,132 |  | 123,523
2022 | 93,583 |  | 94,551
2021 | 22,696 |  | 42,081
2020 | 9,675 |  | 73,652
2019/Prior | 34,625 |  | 10,743
Prior |  |  | 36,193
Total loans | 298,455 |  | 380,743
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Watch List - Doubtful |  |  |
Loan portfolio by credit quality indicator |  |  |
2023 | 25,064 |  |
2022 | 87 |  | 96
Total loans | 25,151 |  | 96
Obligations of states and political subdivisions |  |  |
Loan portfolio by credit quality indicator |  |  |
Total loans | 2,219,432 |  | 2,091,622
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 257,510 |  |
2023 | 950,663 |  | 966,695
2022 | 600,243 |  | 687,012
2021 | 300,974 |  | 324,238
2020 | 95,175 |  | 96,400
2019/Prior | 14,867 |  | 14,058
Prior |  |  | 3,219
Total loans | 2,219,432 |  | 2,091,622
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Pass |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 257,510 |  |
2023 | 922,226 |  | 938,739
2022 | 587,224 |  | 674,037
2021 | 300,974 |  | 324,238
2020 | 95,175 |  | 96,400
2019/Prior | 14,867 |  | 14,058
Prior |  |  | 3,219
Total loans | 2,177,976 |  | 2,050,691
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Watch List - Substandard |  |  |
Loan portfolio by credit quality indicator |  |  |
2023 | 26,090 |  | 25,230
Total loans | 26,090 |  | 25,230
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Watch List - Doubtful |  |  |
Loan portfolio by credit quality indicator |  |  |
2023 | 2,347 |  | 2,726
2022 | 13,019 |  | 12,975
Total loans | 15,366 |  | 15,701
Real estate - mortgage |  |  |
Loan portfolio by credit quality indicator |  |  |
Total loans | 954,469 |  | 938,901
Real estate - mortgage | Domestic | Residential: first lien |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 93,678 |  |
2023 | 116,839 |  | 180,127
2022 | 87,847 |  | 83,661
2021 | 63,298 |  | 68,409
2020 | 32,588 |  | 39,935
2019/Prior | 92,538 |  | 27,499
Prior |  |  | 78,401
Total loans | 486,788 |  | 478,032
Current-period gross writeoffs |  |  |
Prior | 45 |  |
Prior |  |  | 43
Total | 45 |  | 43
Real estate - mortgage | Domestic | Residential: first lien | Pass |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 93,678 |  |
2023 | 116,839 |  | 180,127
2022 | 87,788 |  | 83,568
2021 | 62,974 |  | 68,082
2020 | 32,588 |  | 39,935
2019/Prior | 92,443 |  | 27,499
Prior |  |  | 78,306
Total loans | 486,310 |  | 477,517
Real estate - mortgage | Domestic | Residential: first lien | Watch List - Substandard |  |  |
Loan portfolio by credit quality indicator |  |  |
2021 | 324 |  | 327
2019/Prior | 95 |  |
Prior |  |  | 95
Total loans | 419 |  | 422
Real estate - mortgage | Domestic | Residential: first lien | Watch List - Doubtful |  |  |
Loan portfolio by credit quality indicator |  |  |
2022 | 59 |  | 93
Total loans | 59 |  | 93
Real estate - mortgage | Domestic | Residential Junior Lien |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 21,463 |  |
2023 | 87,649 |  | 88,628
2022 | 73,219 |  | 76,845
2021 | 93,893 |  | 96,411
2020 | 74,000 |  | 76,490
2019/Prior | 117,457 |  | 34,870
Prior |  |  | 87,625
Total loans | 467,681 |  | 460,869
Current-period gross writeoffs |  |  |
Prior |  |  | 298
Total |  | 1 | 298
Real estate - mortgage | Domestic | Residential Junior Lien | Pass |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 21,463 |  |
2023 | 87,649 |  | 88,628
2022 | 73,219 |  | 76,845
2021 | 93,893 |  | 96,411
2020 | 74,000 |  | 76,490
2019/Prior | 117,457 |  | 34,870
Prior |  |  | 87,625
Total loans | 467,681 |  | 460,869
Consumer |  |  |
Loan portfolio by credit quality indicator |  |  |
Total loans | 46,358 |  | 45,121
Consumer | Domestic |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 12,653 |  |
2023 | 27,389 |  | 36,639
2022 | 3,646 |  | 5,366
2021 | 737 |  | 1,043
2020 | 131 |  | 237
2019/Prior | 1,802 |  | 157
Prior |  |  | 1,679
Total loans | 46,358 |  | 45,121
Current-period gross writeoffs |  |  |
2023 | 29 |  | 54
2022 | 9 |  | 115
2021 |  |  | 9
2019 |  |  | 1
Total | 38 | $ 61 | 179
Consumer | Domestic | Pass |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 12,653 |  |
2023 | 27,389 |  | 36,639
2022 | 3,646 |  | 5,366
2021 | 737 |  | 1,043
2020 | 131 |  | 237
2019/Prior | 1,802 |  | 157
Prior |  |  | 1,679
Total loans | 46,358 |  | 45,121
Foreign. |  |  |
Loan portfolio by credit quality indicator |  |  |
Total loans | 176,453 |  | 180,695
Foreign. | Foreign |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 34,788 |  |
2023 | 86,621 |  | 116,104
2022 | 36,585 |  | 43,842
2021 | 11,060 |  | 12,317
2020 | 1,792 |  | 2,016
2019/Prior | 5,607 |  | 2,797
Prior |  |  | 3,619
Total loans | 176,453 |  | 180,695
Foreign. | Foreign | Pass |  |  |
Loan portfolio by credit quality indicator |  |  |
2024 | 34,788 |  |
2023 | 86,621 |  | 116,104
2022 | 36,585 |  | 43,842
2021 | 11,060 |  | 12,317
2020 | 1,792 |  | 2,016
2019/Prior | 5,607 |  | 2,797
Prior |  |  | 3,619
Total loans | $ 176,453 |  | $ 180,695

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