Loans - Impaired Loan Data (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Unpaid Contractual Principal Balance
With No Related Allowance Recorded	$ 19,509	$ 20,129
With An Allowance Recorded	6,511	7,876
Loans Including Purchased Credit Impaired Loans	27,176	28,384
Recorded Investment
With No Related Allowance Recorded	18,671	19,249
With An Allowance Recorded	6,572	7,865
Loans Including Purchased Credit Impaired Loans	26,083	27,361
Related Allowance
With An Allowance Recorded	1,588	1,925
Total Impaired Loans	1,778	2,010
Average Recorded Investment
With No Related Allowance Recorded	19,378	17,499
With An Allowance Recorded	7,187	7,766
Loans Including Purchased Credit Impaired Loans	27,109	25,599
Purchase credit impaired
Unpaid Contractual Principal Balance
Loans Including Purchased Credit Impaired Loans	1,156	379
Recorded Investment
Loans Including Purchased Credit Impaired Loans	840	247
Related Allowance
With An Allowance Recorded	190	85
Purchased Credit Impaired Loans	190	85
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	544	334
Construction, land and land development
Unpaid Contractual Principal Balance
With No Related Allowance Recorded	7,480	6,969
With An Allowance Recorded	0	0
Loans Including Purchased Credit Impaired Loans	7,596	7,087
Recorded Investment
With No Related Allowance Recorded	7,480	6,982
With An Allowance Recorded	0	0
Loans Including Purchased Credit Impaired Loans	7,528	7,076
Related Allowance
With An Allowance Recorded	0	0
Total Impaired Loans	38	0
Average Recorded Investment
With No Related Allowance Recorded	7,231	2,841
With An Allowance Recorded	0	0
Loans Including Purchased Credit Impaired Loans	7,302	2,937
Construction, land and land development | Purchase credit impaired
Unpaid Contractual Principal Balance
Loans Including Purchased Credit Impaired Loans	116	118
Recorded Investment
Loans Including Purchased Credit Impaired Loans	48	94
Related Allowance
With An Allowance Recorded	38	0
Purchased Credit Impaired Loans	38	0
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	71	96
Commercial real estate
Unpaid Contractual Principal Balance
With No Related Allowance Recorded	10,979	11,978
With An Allowance Recorded	5,242	6,292
Loans Including Purchased Credit Impaired Loans	17,001	18,270
Recorded Investment
With No Related Allowance Recorded	10,121	11,105
With An Allowance Recorded	5,247	6,325
Loans Including Purchased Credit Impaired Loans	16,132	17,430
Related Allowance
With An Allowance Recorded	1,315	1,436
Total Impaired Loans	1,357	1,436
Average Recorded Investment
With No Related Allowance Recorded	11,042	12,190
With An Allowance Recorded	5,783	5,945
Loans Including Purchased Credit Impaired Loans	17,207	18,198
Commercial real estate | Purchase credit impaired
Unpaid Contractual Principal Balance
Loans Including Purchased Credit Impaired Loans	780	0
Recorded Investment
Loans Including Purchased Credit Impaired Loans	764	0
Related Allowance
With An Allowance Recorded	42	0
Purchased Credit Impaired Loans	42	0
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	382	63
Residential real estate
Unpaid Contractual Principal Balance
With No Related Allowance Recorded	1,047	1,140
With An Allowance Recorded	1,177	1,274
Loans Including Purchased Credit Impaired Loans	2,237	2,428
Recorded Investment
With No Related Allowance Recorded	1,067	1,122
With An Allowance Recorded	1,233	1,230
Loans Including Purchased Credit Impaired Loans	2,301	2,363
Related Allowance
With An Allowance Recorded	229	226
Total Impaired Loans	239	230
Average Recorded Investment
With No Related Allowance Recorded	1,084	2,142
With An Allowance Recorded	1,203	703
Loans Including Purchased Credit Impaired Loans	2,293	2,858
Residential real estate | Purchase credit impaired
Unpaid Contractual Principal Balance
Loans Including Purchased Credit Impaired Loans	13	14
Recorded Investment
Loans Including Purchased Credit Impaired Loans	1	11
Related Allowance
With An Allowance Recorded	10	4
Purchased Credit Impaired Loans	10	4
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	6	13
Commercial, financial & agricultural
Unpaid Contractual Principal Balance
With No Related Allowance Recorded	3	42
With An Allowance Recorded	86	310
Loans Including Purchased Credit Impaired Loans	336	407
Recorded Investment
With No Related Allowance Recorded	3	40
With An Allowance Recorded	86	310
Loans Including Purchased Credit Impaired Loans	116	396
Related Allowance
With An Allowance Recorded	38	263
Total Impaired Loans	138	263
Average Recorded Investment
With No Related Allowance Recorded	21	203
With An Allowance Recorded	198	1,118
Loans Including Purchased Credit Impaired Loans	256	1,370
Commercial, financial & agricultural | Purchase credit impaired
Unpaid Contractual Principal Balance
Loans Including Purchased Credit Impaired Loans	247	55
Recorded Investment
Loans Including Purchased Credit Impaired Loans	27	46
Related Allowance
With An Allowance Recorded	100	0
Purchased Credit Impaired Loans	100	0
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	37	49
Consumer and other
Unpaid Contractual Principal Balance
With No Related Allowance Recorded	0	0
With An Allowance Recorded	6	0
Loans Including Purchased Credit Impaired Loans	6	192
Recorded Investment
With No Related Allowance Recorded	0	0
With An Allowance Recorded	6	0
Loans Including Purchased Credit Impaired Loans	6	96
Related Allowance
With An Allowance Recorded	6	0
Total Impaired Loans	6	81
Average Recorded Investment
With No Related Allowance Recorded	0	123
With An Allowance Recorded	3	0
Loans Including Purchased Credit Impaired Loans	51	236
Consumer and other | Purchase credit impaired
Unpaid Contractual Principal Balance
Loans Including Purchased Credit Impaired Loans	0	192
Recorded Investment
Loans Including Purchased Credit Impaired Loans	0	96
Related Allowance
With An Allowance Recorded	0	81
Purchased Credit Impaired Loans	0	81
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	$ 48	$ 113