Loans - Impaired Loan Data (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Unpaid Contractual Principal Balance
With No Related Allowance Recorded	$ 16,048	$ 15,485
With An Allowance Recorded	8,835	9,325
Loans Including Purchased Credit Impaired Loans	25,398	24,957
Impaired Balance
With No Related Allowance Recorded	15,171	14,674
With An Allowance Recorded	8,835	9,134
Loans Including Purchased Credit Impaired Loans	24,521	23,955
Related Allowance
With An Allowance Recorded	3,157	3,149
Total Impaired Loans	3,257	3,155
Average Recorded Investment
With No Related Allowance Recorded	15,329	18,818
With An Allowance Recorded	9,081	5,067
Loans Including Purchased Credit Impaired Loans	24,740	24,071
Financial Asset Acquired with Credit Deterioration
Unpaid Contractual Principal Balance
Loans Including Purchased Credit Impaired Loans	515	147
Impaired Balance
Loans Including Purchased Credit Impaired Loans	515	147
Related Allowance
Purchased Credit Impaired Loans	100	6
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	330	186
Construction, land and land development
Unpaid Contractual Principal Balance
With No Related Allowance Recorded	66	67
With An Allowance Recorded	0	0
Loans Including Purchased Credit Impaired Loans	185	132
Impaired Balance
With No Related Allowance Recorded	66	67
With An Allowance Recorded	0	0
Loans Including Purchased Credit Impaired Loans	185	132
Related Allowance
With An Allowance Recorded	0	0
Total Impaired Loans	0	0
Average Recorded Investment
With No Related Allowance Recorded	67	168
With An Allowance Recorded	0	80
Loans Including Purchased Credit Impaired Loans	159	328
Construction, land and land development | Financial Asset Acquired with Credit Deterioration
Unpaid Contractual Principal Balance
Loans Including Purchased Credit Impaired Loans	119	65
Impaired Balance
Loans Including Purchased Credit Impaired Loans	119	65
Related Allowance
Purchased Credit Impaired Loans	0	0
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	92	80
Residential real estate
Unpaid Contractual Principal Balance
With No Related Allowance Recorded	2,477	2,706
With An Allowance Recorded	525	757
Loans Including Purchased Credit Impaired Loans	3,020	3,474
Impaired Balance
With No Related Allowance Recorded	2,465	2,711
With An Allowance Recorded	525	760
Loans Including Purchased Credit Impaired Loans	3,008	3,482
Related Allowance
With An Allowance Recorded	99	137
Total Impaired Loans	111	143
Average Recorded Investment
With No Related Allowance Recorded	2,586	3,693
With An Allowance Recorded	641	367
Loans Including Purchased Credit Impaired Loans	3,242	4,084
Residential real estate | Financial Asset Acquired with Credit Deterioration
Unpaid Contractual Principal Balance
Loans Including Purchased Credit Impaired Loans	18	11
Impaired Balance
Loans Including Purchased Credit Impaired Loans	18	11
Related Allowance
Purchased Credit Impaired Loans	12	6
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	15	24
Commercial, financial, & agricultural
Unpaid Contractual Principal Balance
With No Related Allowance Recorded	381	257
With An Allowance Recorded	1,974	2,189
Loans Including Purchased Credit Impaired Loans	2,417	2,483
Impaired Balance
With No Related Allowance Recorded	381	257
With An Allowance Recorded	1,974	1,989
Loans Including Purchased Credit Impaired Loans	2,417	2,283
Related Allowance
With An Allowance Recorded	981	1,073
Total Impaired Loans	981	1,073
Average Recorded Investment
With No Related Allowance Recorded	319	910
With An Allowance Recorded	2,082	722
Loans Including Purchased Credit Impaired Loans	2,450	1,679
Commercial, financial, & agricultural | Financial Asset Acquired with Credit Deterioration
Unpaid Contractual Principal Balance
Loans Including Purchased Credit Impaired Loans	62	37
Impaired Balance
Loans Including Purchased Credit Impaired Loans	62	37
Related Allowance
Purchased Credit Impaired Loans	0	0
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	49	47
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	191	0
Impaired Balance
With No Related Allowance Recorded	0	0
With An Allowance Recorded	0	0
Loans Including Purchased Credit Impaired Loans	191	0
Related Allowance
With An Allowance Recorded	0	0
Total Impaired Loans	88	0
Average Recorded Investment
With No Related Allowance Recorded	0	123
With An Allowance Recorded	0	0
Loans Including Purchased Credit Impaired Loans	95	123
Consumer and other | Financial Asset Acquired with Credit Deterioration
Unpaid Contractual Principal Balance
Loans Including Purchased Credit Impaired Loans	191	0
Impaired Balance
Loans Including Purchased Credit Impaired Loans	191	0
Related Allowance
Purchased Credit Impaired Loans	88	0
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	95	0
Commercial Real Estate Portfolio Segment
Unpaid Contractual Principal Balance
With No Related Allowance Recorded	13,124	12,455
With An Allowance Recorded	6,336	6,379
Loans Including Purchased Credit Impaired Loans	19,585	18,868
Impaired Balance
With No Related Allowance Recorded	12,259	11,639
With An Allowance Recorded	6,336	6,385
Loans Including Purchased Credit Impaired Loans	18,720	18,058
Related Allowance
With An Allowance Recorded	2,077	1,939
Total Impaired Loans	2,077	1,939
Average Recorded Investment
With No Related Allowance Recorded	12,357	13,924
With An Allowance Recorded	6,358	3,898
Loans Including Purchased Credit Impaired Loans	18,794	17,857
Commercial Real Estate Portfolio Segment | Financial Asset Acquired with Credit Deterioration
Unpaid Contractual Principal Balance
Loans Including Purchased Credit Impaired Loans	125	34
Impaired Balance
Loans Including Purchased Credit Impaired Loans	125	34
Related Allowance
Purchased Credit Impaired Loans	0	0
Average Recorded Investment
Loans Including Purchased Credit Impaired Loans	$ 79	$ 35