Loans and Allowance for Loan Losses - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Summary of the allowance for loan losses
Balance at beginning of period	$ 15,693	$ 11,845	$ 12,477	$ 11,652
Additions:
Provision for loan losses	900	250	4,200	400
Deductions:
Loans charged off	117	283	251	480
Less recoveries on loans	(146)	(71)	(196)	(311)
Net loan charge-offs (recoveries)	(29)	212	55	169
Balance at end of period	16,622	11,883	16,622	11,883
Amount of PPP loans funded during the period	$ 87,600
Percentage credit guarantee from the SBA for the PPP loans	100.00%
Allowance for PPP loans	$ 0		0
Minimum
Deductions:
Expected repayment term of the SBA PPP loans	2 months
Maximum
Deductions:
Expected repayment term of the SBA PPP loans	3 months
Commercial, financial, and agricultural
Summary of the allowance for loan losses
Balance at beginning of period	$ 3,623	3,232	2,918	3,237
Additions:
Provision for loan losses	(32)	(327)	689	(388)
Deductions:
Loans charged off	43	140	84	193
Less recoveries on loans	(66)	(18)	(91)	(127)
Net loan charge-offs (recoveries)	(23)	122	(7)	66
Balance at end of period	3,614	2,783	3,614	2,783
Residential real estate | Construction
Summary of the allowance for loan losses
Balance at beginning of period	117	74	64	140
Additions:
Provision for loan losses	22	(17)	75	(83)
Deductions:
Loans charged off	0
Less recoveries on loans	(32)	(12)	(32)	(12)
Net loan charge-offs (recoveries)	(32)	(12)	(32)	(12)
Balance at end of period	171	69	171	69
Residential real estate | Mortgages
Summary of the allowance for loan losses
Balance at beginning of period	2,363	1,890	2,118	2,071
Additions:
Provision for loan losses	354	(27)	609	(223)
Deductions:
Loans charged off	33	96	52	180
Less recoveries on loans	(27)	(5)	(36)	(104)
Net loan charge-offs (recoveries)	6	91	16	76
Balance at end of period	2,711	1,772	2,711	1,772
Commercial real estate | Construction
Summary of the allowance for loan losses
Balance at beginning of period	622	638	369	757
Additions:
Provision for loan losses	100	66	353	(53)
Deductions:
Loans charged off	0
Less recoveries on loans	0
Net loan charge-offs (recoveries)	0
Balance at end of period	722	704	722	704
Commercial real estate | Mortgages
Summary of the allowance for loan losses
Balance at beginning of period	8,614	5,523	6,547	4,914
Additions:
Provision for loan losses	435	591	2,522	1,208
Deductions:
Loans charged off	2	8	24	16
Less recoveries on loans	(1)	(3)	(3)	(3)
Net loan charge-offs (recoveries)	1	5	21	13
Balance at end of period	9,048	6,109	9,048	6,109
Installment and other consumer
Summary of the allowance for loan losses
Balance at beginning of period	351	333	381	334
Additions:
Provision for loan losses	(26)	(20)	(18)	(1)
Deductions:
Loans charged off	39	39	91	91
Less recoveries on loans	(20)	(33)	(34)	(65)
Net loan charge-offs (recoveries)	19	6	57	26
Balance at end of period	306	307	306	307
Unallocated
Summary of the allowance for loan losses
Balance at beginning of period	3	155	80	199
Additions:
Provision for loan losses	47	(16)	(30)	(60)
Deductions:
Loans charged off	0
Less recoveries on loans	0
Net loan charge-offs (recoveries)	0
Balance at end of period	$ 50	$ 139	$ 50	$ 139