Loans - Credit Risk Rating for Commercial, Construction and Non-Consumer Related Loans (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020 USD ($) rating	Dec. 31, 2019 USD ($)
Receivables [Abstract]
Number of risk rating approaches | rating	2
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	$ 639,788	$ 588,646
Commercial and Industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	68,230	45,278
Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	264,492	245,183
Commercial Real Estate | Residential mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	49,826	45,881
Commercial Real Estate | Home improvement and home equity loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	120	173
Real Estate Construction and Development
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	153,655	138,784
Agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	48,979	52,197
Commercial, Construction and Other Non-Consumer Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	535,356	481,442
Installment and student loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	64,352	69,878
Real Estate and Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	114,298	115,932
Grades 1 and 2 | Commercial and Industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	26,306	278
Grades 1 and 2 | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	2,767	2,806
Grades 1 and 2 | Real Estate Construction and Development
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	0	0
Grades 1 and 2 | Agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	0	0
Grades 1 and 2 | Commercial, Construction and Other Non-Consumer Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	29,073	3,084
Grade 3 | Commercial and Industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	0	0
Grade 3 | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	751	981
Grade 3 | Real Estate Construction and Development
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	0	0
Grade 3 | Agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	0	0
Grade 3 | Commercial, Construction and Other Non-Consumer Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	751	981
Grades 4 and 5 – pass | Commercial and Industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	40,073	41,757
Grades 4 and 5 – pass | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	258,108	238,612
Grades 4 and 5 – pass | Real Estate Construction and Development
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	141,548	126,308
Grades 4 and 5 – pass | Agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	45,966	50,234
Grades 4 and 5 – pass | Commercial, Construction and Other Non-Consumer Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	485,695	456,911
Grade 6 – special mention | Commercial and Industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	1,275	919
Grade 6 – special mention | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	1,715	1,608
Grade 6 – special mention | Real Estate Construction and Development
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	998	998
Grade 6 – special mention | Agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	2,320	1,279
Grade 6 – special mention | Commercial, Construction and Other Non-Consumer Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	6,308	4,804
Grade 7 – substandard | Commercial and Industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	576	2,324
Grade 7 – substandard | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	1,151	1,176
Grade 7 – substandard | Real Estate Construction and Development
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	11,109	11,478
Grade 7 – substandard | Agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	693	684
Grade 7 – substandard | Commercial, Construction and Other Non-Consumer Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	13,529	15,662
Grade 8 – doubtful | Commercial and Industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	0	0
Grade 8 – doubtful | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	0	0
Grade 8 – doubtful | Real Estate Construction and Development
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	0	0
Grade 8 – doubtful | Agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	0	0
Grade 8 – doubtful | Commercial, Construction and Other Non-Consumer Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	0	0
Not graded | Commercial Real Estate | Residential mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	35,163	33,059
Not graded | Commercial Real Estate | Home improvement and home equity loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	103	155
Not graded | Installment and student loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	63,427	68,752
Not graded | Real Estate and Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	98,693	101,966
Pass | Commercial Real Estate | Residential mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	14,123	12,542
Pass | Commercial Real Estate | Home improvement and home equity loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	17	18
Pass | Installment and student loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	656	740
Pass | Real Estate and Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	14,796	13,300
Special mention | Commercial Real Estate | Residential mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	357	88
Special mention | Commercial Real Estate | Home improvement and home equity loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	0	0
Special mention | Installment and student loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	269	386
Special mention | Real Estate and Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	626	474
Substandard | Commercial Real Estate | Residential mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	183	192
Substandard | Commercial Real Estate | Home improvement and home equity loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	0	0
Substandard | Installment and student loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	0	0
Substandard | Real Estate and Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	183	192
Doubtful | Commercial Real Estate | Residential mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	0	0
Doubtful | Commercial Real Estate | Home improvement and home equity loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	0	0
Doubtful | Installment and student loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	0	0
Doubtful | Real Estate and Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Loans outstanding	$ 0	$ 0
Minimum | Grades 4 and 5 – pass
Financing Receivable, Credit Quality Indicator [Line Items]
Notes receivable, period of loss recognition	3 years
Maximum | Grades 4 and 5 – pass
Financing Receivable, Credit Quality Indicator [Line Items]
Notes receivable, period of loss recognition	4 years