Loans - Impaired Loan Data (Details) - USD ($) $ in Thousands		9 Months Ended
	Dec. 31, 2019	Sep. 30, 2020
Unpaid Contractual Principal Balance
With No Related Allowance Recorded	$ 15,485	$ 23,638
With An Allowance Recorded	9,325	3,437
Loans Including Purchased Credit Impaired Loans	24,957	27,578
Recorded Investment
With No Related Allowance Recorded	14,674	22,953
With An Allowance Recorded	9,134	3,442
Loans Including Purchased Credit Impaired Loans	23,955	26,898
Related Allowance
With An Allowance Recorded	3,149	1,369
Total Impaired Loans	3,155	1,457
Average Recorded Investment
With No Related Allowance Recorded	18,818	12,942
With An Allowance Recorded	5,067	11,725
Loans Including Purchased Credit Impaired Loans	24,071	25,023
Purchase credit impaired
Unpaid Contractual Principal Balance
Loans Including Purchased Credit Impaired Loans	147	503
Recorded Investment
Loans Including Purchased Credit Impaired Loans	147	503
Related Allowance
Purchased Credit Impaired Loans	6	88
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	186	356
Construction, land and land development
Unpaid Contractual Principal Balance
With No Related Allowance Recorded	67	6,970
With An Allowance Recorded	0	0
Loans Including Purchased Credit Impaired Loans	132	7,088
Recorded Investment
With No Related Allowance Recorded	67	7,023
With An Allowance Recorded	0	0
Loans Including Purchased Credit Impaired Loans	132	7,141
Related Allowance
With An Allowance Recorded	0	0
Total Impaired Loans	0	0
Average Recorded Investment
With No Related Allowance Recorded	168	1,806
With An Allowance Recorded	80	0
Loans Including Purchased Credit Impaired Loans	328	1,902
Construction, land and land development | Purchase credit impaired
Unpaid Contractual Principal Balance
Loans Including Purchased Credit Impaired Loans	65	118
Recorded Investment
Loans Including Purchased Credit Impaired Loans	65	118
Related Allowance
Purchased Credit Impaired Loans	0	0
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	80	96
Residential real estate
Unpaid Contractual Principal Balance
With No Related Allowance Recorded	2,706	1,985
With An Allowance Recorded	757	480
Loans Including Purchased Credit Impaired Loans	3,474	2,481
Recorded Investment
With No Related Allowance Recorded	2,711	1,949
With An Allowance Recorded	760	480
Loans Including Purchased Credit Impaired Loans	3,482	2,445
Related Allowance
With An Allowance Recorded	137	74
Total Impaired Loans	143	79
Average Recorded Investment
With No Related Allowance Recorded	3,693	1,926
With An Allowance Recorded	367	1,059
Loans Including Purchased Credit Impaired Loans	4,084	2,999
Residential real estate | Purchase credit impaired
Unpaid Contractual Principal Balance
Loans Including Purchased Credit Impaired Loans	11	16
Recorded Investment
Loans Including Purchased Credit Impaired Loans	11	16
Related Allowance
Purchased Credit Impaired Loans	6	5
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	24	14
Commercial, financial, & agricultural
Unpaid Contractual Principal Balance
With No Related Allowance Recorded	257	48
With An Allowance Recorded	2,189	567
Loans Including Purchased Credit Impaired Loans	2,483	672
Recorded Investment
With No Related Allowance Recorded	257	48
With An Allowance Recorded	1,989	567
Loans Including Purchased Credit Impaired Loans	2,283	672
Related Allowance
With An Allowance Recorded	1,073	567
Total Impaired Loans	1,073	567
Average Recorded Investment
With No Related Allowance Recorded	910	232
With An Allowance Recorded	722	1,332
Loans Including Purchased Credit Impaired Loans	1,679	1,614
Commercial, financial, & agricultural | Purchase credit impaired
Unpaid Contractual Principal Balance
Loans Including Purchased Credit Impaired Loans	37	57
Recorded Investment
Loans Including Purchased Credit Impaired Loans	37	57
Related Allowance
Purchased Credit Impaired Loans	0	0
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	47	50
Consumer and other
Unpaid Contractual Principal Balance
With No Related Allowance Recorded	0	0
With An Allowance Recorded	0	0
Loans Including Purchased Credit Impaired Loans	0	192
Recorded Investment
With No Related Allowance Recorded	0	0
With An Allowance Recorded	0	0
Loans Including Purchased Credit Impaired Loans	0	192
Related Allowance
With An Allowance Recorded	0	0
Total Impaired Loans	0	83
Average Recorded Investment
With No Related Allowance Recorded	123	0
With An Allowance Recorded	0	0
Loans Including Purchased Credit Impaired Loans	123	117
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	192
Related Allowance
Purchased Credit Impaired Loans	0	83
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	0	117
Commercial Real Estate Portfolio Segment
Unpaid Contractual Principal Balance
With No Related Allowance Recorded	12,455	14,635
With An Allowance Recorded	6,379	2,390
Loans Including Purchased Credit Impaired Loans	18,868	17,145
Recorded Investment
With No Related Allowance Recorded	11,639	13,933
With An Allowance Recorded	6,385	2,395
Loans Including Purchased Credit Impaired Loans	18,058	16,448
Related Allowance
With An Allowance Recorded	1,939	728
Total Impaired Loans	1,939	728
Average Recorded Investment
With No Related Allowance Recorded	13,924	8,978
With An Allowance Recorded	3,898	9,334
Loans Including Purchased Credit Impaired Loans	17,857	18,391
Commercial Real Estate Portfolio Segment | Purchase credit impaired
Unpaid Contractual Principal Balance
Loans Including Purchased Credit Impaired Loans	34	120
Recorded Investment
Loans Including Purchased Credit Impaired Loans	34	120
Related Allowance
Purchased Credit Impaired Loans	0	0
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	$ 35	$ 79