Loans - Credit Quality Indicators (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Credit quality categories
Total	$ 1,348,407	$ 1,354,357
Pass
Credit quality categories
Total	1,326,639	1,328,050
Special Mention
Credit quality categories
Total	16,865	10,690
Substandard
Credit quality categories
Total	4,903	15,617
Commercial, financial, and agricultural
Credit quality categories
Total	168,904	156,213
Commercial, financial, and agricultural | Pass
Credit quality categories
Total	162,604	149,349
Commercial, financial, and agricultural | Special Mention
Credit quality categories
Total	5,043	3,174
Commercial, financial, and agricultural | Substandard
Credit quality categories
Total	1,257	3,690
Consumer automobile
Credit quality categories
Total	155,721	150,517
Consumer automobile | Pass
Credit quality categories
Total	155,694	150,517
Consumer automobile | Special Mention
Credit quality categories
Total	0	0
Consumer automobile | Substandard
Credit quality categories
Total	27	0
Other consumer installment loans
Credit quality categories
Total	21,018	23,043
Other consumer installment loans | Pass
Credit quality categories
Total	21,018	23,039
Other consumer installment loans | Special Mention
Credit quality categories
Total	0	0
Other consumer installment loans | Substandard
Credit quality categories
Total	0	4
Residential | Real Estate Mortgages
Credit quality categories
Total	606,214	623,256
Residential | Real Estate Mortgages | Pass
Credit quality categories
Total	603,806	618,350
Residential | Real Estate Mortgages | Special Mention
Credit quality categories
Total	1,444	2,436
Residential | Real Estate Mortgages | Substandard
Credit quality categories
Total	964	2,470
Commercial | Real Estate Mortgages
Credit quality categories
Total	352,530	363,261
Commercial | Real Estate Mortgages | Pass
Credit quality categories
Total	339,507	348,864
Commercial | Real Estate Mortgages | Special Mention
Credit quality categories
Total	10,368	5,080
Commercial | Real Estate Mortgages | Substandard
Credit quality categories
Total	2,655	9,317
Construction | Real Estate Mortgages
Credit quality categories
Total	44,020	38,067
Construction | Real Estate Mortgages | Pass
Credit quality categories
Total	44,010	37,931
Construction | Real Estate Mortgages | Special Mention
Credit quality categories
Total	10	0
Construction | Real Estate Mortgages | Substandard
Credit quality categories
Total	$ 0	$ 136