| LOANS HELD FOR INVESTMENT AND ALLOWANCE FOR CREDIT LOSSES (Tables) | 3 Months Ended | 
|---|---|
| Mar. 31, 2024 | |
| Loans Held for Investment and Allowance for Credit Losses [Abstract] | |
| Composition of the loan portfolio | (Dollars in Thousands)  March 31, 2024  December 31, 2023  Commercial, Financial and Agricultural  $  218,298 $  225,190 Real Estate – Construction  202,692 196,091 Real Estate – Commercial Mortgage  823,690 825,456 Real Estate – Residential (1)  1,016,580 1,004,219 Real Estate – Home Equity  214,617 210,920 Consumer (2)  255,295 272,042 Loans Held For Investment, Net of Unearned Income  $  2,731,172 $  2,733,918 (1) Includes loans in process balances of $ 4.4 3.2 (2) Includes overdraft balances of $ 1.1 1.0 | 
| Activity in allowance for loan losses by portfolio class | Commercial,  Real Estate  Financial, Real Estate  Commercial Real Estate  Real Estate  (Dollars in Thousands)  Agricultural  Construction  Mortgage  Residential  Home Equity  Consumer  Total  Three Months Ended  March 31, 2024  Beginning Balance  $  1,482 $  2,502 $  5,782 $  15,056 $  1,818 $  3,301 $  29,941 Provision for Credit Losses  284 (633) (39) (248) 130 1,388 882 Charge-Offs  (282) - - (17) (76) (2,188) (2,563) Recoveries 41 - 204 37 24 763 1,069 Net (Charge-Offs) Recoveries  (241) - 204 20 (52) (1,425) (1,494) Ending Balance  $  1,525 $  1,869 $  5,947 $  14,828 $  1,896 $  3,264 $  29,329 Three Months Ended  March 31, 2023  Beginning Balance  $  1,506 $  2,654 $  4,815 $  10,741 $  1,864 $  3,488 $  25,068 Provision for Credit Losses  78 704 7 1,152 (10) 1,329 3,260 Charge-Offs  (164) - (120) - - (2,366) (2,650) Recoveries 95 1 8 57 25 944 1,130 Net (Charge-Offs) Recoveries  (69) 1 (112) 57 25 (1,422) (1,520) Ending Balance  $  1,515 $  3,359 $  4,710 $  11,950 $  1,879 $  3,395 $  26,808 | 
| Loan Portfolio Aging | 30-59 60-89 90 + Total  Total  Nonaccrual  Total  (Dollars in Thousands)  DPD  DPD  DPD  Past Due  Current  Loans  Loans  March 31, 2024  Commercial, Financial and Agricultural  $  567 $  68 $  - $  635 $  217,357 $  306 $  218,298 Real Estate – Construction  - - - - 202,370 322 202,692 Real Estate – Commercial Mortgage  879 - - 879 821,379 1,432 823,690 Real Estate – Residential  1,040 2 - 1,042 1,012,210 3,328 1,016,580 Real Estate – Home Equity  101 - - 101 213,766 750 214,617 Consumer  2,412 323 - 2,735 251,900 660 255,295 Total  $  4,999 $  393 $  - $  5,392 $  2,718,982 $  6,798 $  2,731,172 December 31, 2023  Commercial, Financial and Agricultural  $  311 $  105 $  - $  416 $  224,463 $  311 $  225,190 Real Estate – Construction  206 - - 206 195,563 322 196,091 Real Estate – Commercial Mortgage  794 - - 794 823,753 909 825,456 Real Estate – Residential  670 34 - 704 1,000,525 2,990 1,004,219 Real Estate – Home Equity  268 - - 268 209,653 999 210,920 Consumer  3,693 774 - 4,467 266,864 711 272,042 Total $  5,942 $  913 $  - $  6,855 $  2,720,821 $  6,242 $  2,733,918 | 
| Recorded investment in nonaccrual and past due loans | March 31, 2024  December 31, 2023  Nonaccrual  Nonaccrual  Nonaccrual  Nonaccrual  With No  With  90 + Days  With No  With  90 + Days  (Dollars in Thousands)  ACL  ACL  Still Accruing  ACL  ACL  Still Accruing  Commercial, Financial and Agricultural  $  - $  306 $  - $  - $  311 $  - Real Estate – Construction  - 322 - - 322 - Real Estate – Commercial Mortgage  1,295 137 - 781 128 - Real Estate – Residential  2,102 1,226 - 1,705 1,285 - Real Estate – Home Equity  323 427 - - 999 - Consumer  - 660 - - 711 - Total Nonaccrual $  3,720 $  3,078 $  - $  2,486 $  3,756 $  - | 
| Collateral-dependent loans | March 31, 2024  December 31, 2023  Real Estate  Non Real Estate  Real Estate  Non Real Estate  (Dollars in Thousands)  Secured  Secured  Secured  Secured  Commercial, Financial and Agricultural  $  - $  30 $  - $  30 Real Estate – Construction  275 - 275 - Real Estate – Commercial Mortgage  1,295 - 1,296 - Real Estate – Residential  2,102 - 1,706 - Real Estate – Home Equity  323 - - - Consumer  - - - - Total Collateral Dependent $  3,995 $  30 $  3,277 $  30 | 
| Loans held for investment by years of origination | (Dollars in Thousands)  Term Revolving  As of March 31, 2024  2024  2023  2022  2021  2020  Prior  Loans  Total  Commercial, Financial,  Agriculture:  Pass  $  8,690 $  54,213 $  60,831 $  25,989 $  9,022 $  13,831 $  43,073 $  215,649 Special Mention  224 153 542 305 9 5 698 1,936 Substandard  - 158 89 73 90 142 161 713 Total  $  8,914 $  54,524 $  61,462 $  26,367 $  9,121 $  13,978 $  43,932 $  218,298 Current-Period Gross  Writeoffs  $  - $  16 $  167 $  73 $  6 $  - $  20 $  282 Real Estate -  Construction:  Pass  $  9,733 $  121,495 $  52,078 $  12,036 $  - $  187 $  4,833 $  200,362 Special Mention  - 668 520 290 210 - - 1,688 Substandard  - - 74 568 - - - 642 Total  $  9,733 $  122,163 $  52,672 $  12,894 $  210 $  187 $  4,833 $  202,692 Real Estate -  Commercial Mortgage:  Pass  $  17,060 $  114,391 $  271,591 $  132,081 $  98,214 $  146,120 $  17,344 $  796,801 Special Mention  - 5,573 5,633 - 795 1,995 - 13,996 Substandard  - - 1,204 6,599 2,271 2,120 699 12,893 Total  $  17,060 $  119,964 $  278,428 $  138,680 $  101,280 $  150,235 $  18,043 $  823,690 Real Estate - Residential:  Pass  $  38,629 $  358,059 $  390,522 $  80,624 $  35,045 $  95,003 $  8,509 $  1,006,391 Special Mention  - 267 88 82 494 163 - 1,094 Substandard  - - 1,512 2,526 1,028 4,029 - 9,095 Total $  38,629 $  358,326 $  392,122 $  83,232 $  36,567 $  99,195 $  8,509 $  1,016,580 Current-Period Gross  Writeoffs  $  - $  13 $  - $  - $  - $  4 $  - $  17 Real Estate - Home  Equity:  Performing  $  11 $  507 $  47 $  130 $  10 $  2,388 $  210,775 $  213,868 Nonperforming  - - - - - - 749 749 Total $  11 $  507 $  47 $  130 $  10 $  2,388 $  211,524 $  214,617 Current-Period Gross  Writeoffs  $  - $  - $  - $  - $  - $  - $  76 $  76 Consumer:  Performing  $  11,402 $  63,285 $  80,641 $  63,277 $  18,244 $  10,864 $  6,304 $  254,017 Nonperforming  - 151 291 84 69 44 639 1,278 Total  $  11,402 $  63,436 $  80,932 $  63,361 $  18,313 $  10,908 $  6,943 $  255,295 Current-Period Gross  Writeoffs  $  638 $  418 $  697 $  231 $  92 $  35 $  77 $  2,188 (Dollars in Thousands)  Term Revolving  As of December 31, 2023  2023  2022  2021  2020  2019  Prior  Loans  Total  Commercial, Financial,  Agriculture:  Pass  $  57,320 $  66,671 $  28,933 $  10,610 $  7,758 $  7,502 $  44,350 $  223,144 Special Mention  168 608 356 10 9 - 76 1,227 Substandard  164 177 98 77 20 122 161 819 Total  $  57,652 $  67,456 $  29,387 $  10,697 $  7,787 $  7,624 $  44,587 $  225,190 Current-Period Gross  Writeoffs  $  6 $  252 $  65 $  31 $  41 $  19 $  97 $  511 Real Estate - Construction:  Pass  $  101,684 $  68,265 $  18,181 $  - $  188 $  - $  4,617 $  192,935 Special Mention  631 500 539 212 - - - 1,882 Substandard  - 47 576 651 - - - 1,274 Total  $  102,315 $  68,812 $  19,296 $  863 $  188 $  - $  4,617 $  196,091 Real Estate - Commercial  Mortgage:  Pass  $  117,840 $  275,079 $  135,663 $  101,210 $  43,878 $  109,878 $  18,367 $  801,915 Special Mention  3,266 5,684 - 229 1,358 573 - 11,110 Substandard  - 1,226 6,695 1,637 605 1,574 694 12,431 Total  $  121,106 $  281,989 $  142,358 $  103,076 $  45,841 $  112,025 $  19,061 $  825,456 Current-Period Gross  Writeoffs  $  - $  - $  - $  - $  - $  120 $  - $  120 Real Estate - Residential:  Pass  $  372,394 $  400,437 $  83,108 $  35,879 $  24,848 $  68,685 $  8,252 $  993,603 Special Mention  268 89 83 502 - 313 - 1,255 Substandard  570 1,110 1,906 1,626 1,007 3,142 - 9,361 Total $  373,232 $  401,636 $  85,097 $  38,007 $  25,855 $  72,140 $  8,252 $  1,004,219 Current-Period Gross  Writeoffs  $  - $  - $  79 $  - $  - $  - $  - $  79 Real Estate - Home  Equity:  Performing  $  890 $  48 $  127 $  11 $  386 $  950 $  207,509 $  209,921 Nonperforming  - - - - - - 999 999 Total $  890 $  48 $  127 $  11 $  386 $  950 $  208,508 $  210,920 Current-Period Gross  Writeoffs  $  - $  - $  - $  - $  - $  - $  39 $  39 Consumer:  Performing  $  68,496 $  90,031 $  70,882 $  21,314 $  10,210 $  4,258 $  5,431 $  270,622 Nonperforming  293 355 58 4 - - 710 1,420 Total  $  68,789 $  90,386 $  70,940 $  21,318 $  10,210 $  4,258 $  6,141 $  272,042 Current-Period Gross  Writeoffs  $  3,137 $  3,224 $  1,362 $  329 $  230 $  99 $  162 $  8,543 |