| LOANS HELD FOR INVESTMENT AND ALLOWANCE FOR CREDIT LOSSES (Tables) | 9 Months Ended | 
|---|---|
| Sep. 30, 2021 | |
| Loans Held For Investment And Allowance For Credit Losses [Abstract] | |
| Schedule of composition of the loan portfolio | (Dollars in Thousands)  September 30, 2021  December 31, 2020  Commercial, Financial and Agricultural  $  218,929 $  393,930 Real Estate – Construction  177,443 135,831 Real Estate – Commercial Mortgage  683,379 648,393 Real Estate – Residential (1)  362,750 352,543 Real Estate – Home Equity  187,642 205,479 Consumer (2)  311,282 270,250 Loans HFI, Net of Unearned Income  $  1,941,425 $  2,006,426 (1) Includes loans in process with outstanding balances 7.1 10.9 2020, (2) Includes overdraft balances of $ 1.3 0.7 | 
| Schedule of activity in the 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 September 30, 2021  Beginning Balance  $  1,972 $  2,759 $  7,569 $  4,353 $  2,457 $  3,065 $  22,175 Provision for Credit Losses  178 517 (1,588) (433) (131) 911 (546) Charge-Offs  (37) - (405) (17) (15) (1,314) (1,788) Recoveries 66 10 169 401 46 967 1,659 Net (Charge-Offs) Recoveries  29 10 (236) 384 31 (347) (129) Ending Balance  $  2,179 $  3,286 $  5,745 $  4,304 $  2,357 $  3,629 $  21,500 Nine Months Ended September 30, 2021  Beginning Balance  $  2,204 $  2,479 $  7,029 $  5,440 $  3,111 $  3,553 $  23,816 Provision for Credit Losses  (192) 797 (1,719) (1,768) (900) 740 (3,042) Charge-Offs  (138) - (405) (88) (94) (3,040) (3,765) Recoveries  305 10 840 720 240 2,376 4,491 Net (Charge-Offs) Recoveries  167 10 435 632 146 (664) 726 Ending Balance  $  2,179 $  3,286 $  5,745 $  4,304 $  2,357 $  3,629 $  21,500 Three Months Ended  September 30, 2020  Beginning Balance  $  2,468 $  1,955 $  6,640 $  5,440 $  2,753 $  3,201 $  22,457 Provision for Credit Losses  (195) 161 616 (344) 196 831 1,265 Charge-Offs  (137) - (17) (1) (58) (1,069) (1,282) Recoveries 74 - 30 35 41 517 697 Net Charge-Offs  (63) - 13 34 (17) (552) (585) Ending Balance  $  2,210 $  2,116 $  7,269 $  5,130 $  2,932 $  3,480 $  23,137 Nine Months Ended September 30, 2020  Beginning Balance  $  1,675 $  370 $  3,416 $  3,128 $  2,224 $  3,092 $  13,905 Impact of Adopting ASC 326  488 302 1,458 1,243 374 (596) 3,269 Provision for Credit Losses  544 1,444 2,132 745 337 2,668 7,870 Charge-Offs  (685) - (28) (112) (141) (3,810) (4,776) Recoveries  188 - 291 126 138 2,126 2,869 Net Charge-Offs  (497) - 263 14 (3) (1,684) (1,907) Ending Balance  $  2,210 $  2,116 $  7,269 $  5,130 $  2,932 $  3,480 $  23,137 | 
| Schedule of aging of the recorded investment in accruing past due loans by class of loans | 30-59 60-89 90 + Total  Total  Nonaccrual  Total  (Dollars in Thousands)  DPD  DPD  DPD  Past Due  Current  Loans  Loans  September 30, 2021  Commercial, Financial and Agricultural  $  499 $  36 $  - $  535 $  218,353 $  41 $  218,929 Real Estate – Construction  - - - - 177,443 - 177,443 Real Estate – Commercial Mortgage  364 - - 364 683,015 - 683,379 Real Estate – Residential  735 177 - 912 359,861 1,977 362,750 Real Estate – Home Equity  76 19 - 95 186,581 966 187,642 Consumer  1,196 258 - 1,454 309,786 42 311,282 Total  $  2,870 $  490 $  - $  3,360 $  1,935,039 $  3,026 $  1,941,425 December 31, 2020  Commercial, Financial and Agricultural  $  194 $  124 $  - $  318 $  393,451 $  161 $  393,930 Real Estate – Construction  - 717 - 717 134,935 179 135,831 Real Estate – Commercial Mortgage  293 - - 293 646,688 1,412 648,393 Real Estate – Residential  375 530 - 905 348,508 3,130 352,543 Real Estate – Home Equity  325 138 - 463 204,321 695 205,479 Consumer  1,556 342 - 1,898 268,058 294 270,250 Total $  2,743 $  1,851 $  - $  4,594 $  1,995,961 $  5,871 $  2,006,426 | 
| Schedule of recorded investment in nonaccrual loans and loans past due over 90 days and still on accrual by class of loans | September 30, 2021  December 31, 2020  Nonaccrual  Nonaccrual  Nonaccrual  Nonaccrual  With  With No  90 + Days  With  With No  90 + Days  (Dollars in Thousands)  ACL  ACL  Still Accruing  ACL  ACL  Still Accruing  Commercial, Financial and Agricultural  $  41 $  - $  - $  161 $  - $  - Real Estate – Construction  - - - 179 - - Real Estate – Commercial Mortgage  - - - 337 1,075 - Real Estate – Residential  1,061 916 - 1,617 1,513 - Real Estate – Home Equity  503 463 - 695 - - Consumer  42 - - 294 - - Total Nonaccrual $  1,647 $  1,379 $  - $  3,283 $  2,588 $  - | 
| Amortized cost basis of collateral-dependent loans | September 30, 2021  December 31, 2020  Real Estate  Non Real Estate  Real Estate  Non Real Estate  (Dollars in Thousands)  Secured  Secured  Secured  Secured  Commercial, Financial and Agricultural  $  - $  - $  - $  - Real Estate – Commercial Mortgage  - - 3,900 - Real Estate – Residential  1,891 - 3,022 - Real Estate – Home Equity  665 - 219 - Consumer  - - - 29 Total Collateral Dependent $  2,556 $  - $  7,141 $  29 | 
| Summary of gross loans held for investment by years of origination | Term Revolving  (Dollars in Thousands)  2021  2020  2019  2018  2017  Prior  Loans  Total  Commercial, Financial,  Agriculture:  Pass  $  51,866 $  38,453 $  34,226 $  22,539 $  10,376 $  14,072 $  46,969 $  218,501 Special Mention  - - 70 12 - 49 - 131 Substandard  - 10 - 204 6 77 - 297 Total  $  51,866 $  38,463 $  34,296 $  22,755 $  10,382 $  14,198 $  46,969 $  218,929 Real Estate -  Construction:  Pass  $  75,222 $  72,664 $  23,588 $  429 $  132 $  - $  5,408 $  177,443 Total  $  75,222 $  72,664 $  23,588 $  429 $  132 $  - $  5,408 $  177,443 Real Estate -  Commercial Mortgage:  Pass  $  139,623 $  142,833 $  87,251 $  103,059 $  67,392 $  97,842 $  19,690 $  657,690 Special Mention  - 454 1,552 9,727 431 5,423 - 17,587 Substandard  1,520 585 3,517 - 1,266 990 224 8,102 Total  $  141,143 $  143,872 $  92,320 $  112,786 $  69,089 $  104,255 $  19,914 $  683,379 Real Estate - Residential:  Pass  $  105,611 $  72,091 $  44,393 $  29,792 $  28,447 $  66,748 $  8,538 $  355,620 Special Mention  - 136 20 122 169 419 - 866 Substandard  1,290 441 1,051 812 221 2,373 76 6,264 Total $  106,901 $  72,668 $  45,464 $  30,726 $  28,837 $  69,540 $  8,614 $  362,750 Real Estate - Home  Equity:  Performing  $  99 $  56 $  452 $  176 $  749 $  1,756 $  183,388 $  186,676 Nonperforming  - - - - - 33 933 966 Total $  99 $  56 $  452 $  176 $  749 $  1,789 $  184,321 $  187,642 Consumer:  Performing  $  136,780 $  73,778 $  45,252 $  31,530 $  13,377 $  4,666 $  5,857 $  311,240 Nonperforming  - - 17 24 - 1 - 42 Total  $  136,780 $  73,778 $  45,269 $  31,554 $  13,377 $  4,667 $  5,857 $  311,282 |