Fair Value Measurements - Other Real Estate Owned and Repossessed Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Total Gains (Losses) | Installment and Other Consumer
Fair Value Measurements
Gains (losses) on impaired loans	$ (38)	$ 0	$ (38)	$ (6)
Nonrecurring | Fair value
Fair Value Measurements
Impaired loans	15,898	26,550	15,898	26,550
Other real estate and repossessed assets	9,210	11,614	9,210	11,614
Nonrecurring | Fair value | Commercial, financial, & agricultural
Fair Value Measurements
Impaired loans		3,960		3,960
Nonrecurring | Fair value | Real estate mortgage - residential | Mortgage
Fair Value Measurements
Impaired loans		324		324
Nonrecurring | Fair value | Real estate construction − commercial & Real estate mortgage − commercial | Mortgage
Fair Value Measurements
Impaired loans	15,898	22,266	15,898	22,266
Nonrecurring | Fair value | Installment and Other Consumer
Fair Value Measurements
Impaired loans	0	0	0	0
Nonrecurring | Total Gains (Losses)
Fair Value Measurements
Gains (losses) on impaired loans	(61)	(33)	(86)	(69)
Gains (losses) on other real estate and repossessed assets	0	(12)	(22)	(71)
Nonrecurring | Total Gains (Losses) | Commercial, financial, & agricultural
Fair Value Measurements
Gains (losses) on impaired loans		0		0
Nonrecurring | Total Gains (Losses) | Real estate mortgage - residential | Mortgage
Fair Value Measurements
Gains (losses) on impaired loans		(18)		(22)
Nonrecurring | Total Gains (Losses) | Real estate construction − commercial & Real estate mortgage − commercial | Mortgage
Fair Value Measurements
Gains (losses) on impaired loans	(23)	(15)	(48)	(41)
Nonrecurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value
Fair Value Measurements
Impaired loans	0	0	0	0
Other real estate and repossessed assets	0	0	0	0
Nonrecurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value | Commercial, financial, & agricultural
Fair Value Measurements
Impaired loans		0		0
Nonrecurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value | Real estate mortgage - residential | Mortgage
Fair Value Measurements
Impaired loans		0		0
Nonrecurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value | Real estate construction − commercial & Real estate mortgage − commercial | Mortgage
Fair Value Measurements
Impaired loans	0	0	0	0
Nonrecurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value | Installment and Other Consumer
Fair Value Measurements
Impaired loans	0	0	0	0
Nonrecurring | Other Observable Inputs (Level 2) | Fair value
Fair Value Measurements
Impaired loans	0	0	0	0
Other real estate and repossessed assets	0	0	0	0
Nonrecurring | Other Observable Inputs (Level 2) | Fair value | Commercial, financial, & agricultural
Fair Value Measurements
Impaired loans		0		0
Nonrecurring | Other Observable Inputs (Level 2) | Fair value | Real estate mortgage - residential | Mortgage
Fair Value Measurements
Impaired loans		0		0
Nonrecurring | Other Observable Inputs (Level 2) | Fair value | Real estate construction − commercial & Real estate mortgage − commercial | Mortgage
Fair Value Measurements
Impaired loans	0	0	0	0
Nonrecurring | Other Observable Inputs (Level 2) | Fair value | Installment and Other Consumer
Fair Value Measurements
Impaired loans	0	0	0	0
Nonrecurring | Significant Unobservable Inputs (Level 3) | Fair value
Fair Value Measurements
Impaired loans	15,898	26,550	15,898	26,550
Other real estate and repossessed assets	9,210	11,614	9,210	11,614
Nonrecurring | Significant Unobservable Inputs (Level 3) | Fair value | Commercial, financial, & agricultural
Fair Value Measurements
Impaired loans		3,960		3,960
Nonrecurring | Significant Unobservable Inputs (Level 3) | Fair value | Real estate mortgage - residential | Mortgage
Fair Value Measurements
Impaired loans		324		324
Nonrecurring | Significant Unobservable Inputs (Level 3) | Fair value | Real estate construction − commercial & Real estate mortgage − commercial | Mortgage
Fair Value Measurements
Impaired loans	15,898	22,266	15,898	22,266
Nonrecurring | Significant Unobservable Inputs (Level 3) | Fair value | Installment and Other Consumer
Fair Value Measurements
Impaired loans	$ 0	$ 0	$ 0	$ 0