Loans, Part VI (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) segment loan	Dec. 31, 2019 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Financing Receivable, Allowance for Credit Loss [Line Items]
Number of loan portfolio segment | segment	10
Number of loans entity experienced losses over past twelve quarters | loan	3
Summarizes activity in allowance for credit losses by loan category [Roll Forward]
Beginning balance	$ 7,908	$ 8,395
(Recovery of provision) provision for credit losses	2,769	20
Charge-offs	(2,320)	(813)
Recoveries	165	306
Net recoveries (charge-offs)	(2,155)	(507)
Ending balance	8,522	7,908
Period-end amount allocated to:
Loans individually evaluated for impairment			$ 209	$ 1,145
Loans collectively evaluated for impairment			8,313	6,763
Ending balance	8,522	8,395	8,522	7,908
Loans Individually Evaluated for Impairment			13,376	17,072
Loans Collectively Evaluated for Impairment			642,035	580,302
Loans and leases receivable, before fees, gross			655,411	597,374
Commercial And Industrial
Summarizes activity in allowance for credit losses by loan category [Roll Forward]
Beginning balance	1,322	1,673
(Recovery of provision) provision for credit losses	(726)	421
Charge-offs	0	0
Recoveries	29	70
Net recoveries (charge-offs)	29	70
Ending balance	625	1,322
Period-end amount allocated to:
Loans individually evaluated for impairment			0	606
Loans collectively evaluated for impairment			625	716
Ending balance	1,322	1,322	625	1,322
Loans Individually Evaluated for Impairment			466	1,754
Loans Collectively Evaluated for Impairment			47,048	43,524
Loans and leases receivable, before fees, gross			47,514	45,278
Commercial And Industrial | Commercial and business loans
Period-end amount allocated to:
Loans Individually Evaluated for Impairment			251	1,496
Loans Collectively Evaluated for Impairment			37,098	43,038
Loans and leases receivable, before fees, gross			37,349	44,534
Commercial And Industrial | Government program loans
Period-end amount allocated to:
Loans Individually Evaluated for Impairment			215	258
Loans Collectively Evaluated for Impairment			9,950	486
Loans and leases receivable, before fees, gross			10,165	744
Real Estate Mortgage
Summarizes activity in allowance for credit losses by loan category [Roll Forward]
Beginning balance	712	1,015
(Recovery of provision) provision for credit losses	(227)	352
Charge-offs	(1)	(16)
Recoveries	91	65
Net recoveries (charge-offs)	90	49
Ending balance	575	712
Period-end amount allocated to:
Loans individually evaluated for impairment			13	283
Loans collectively evaluated for impairment			562	429
Ending balance	712	712	575	712
Loans Individually Evaluated for Impairment			1,244	3,146
Loans Collectively Evaluated for Impairment			319,050	288,091
Loans and leases receivable, before fees, gross			320,294	291,237
Real Estate Mortgage | Commercial real estate
Period-end amount allocated to:
Loans Individually Evaluated for Impairment			878	2,083
Loans Collectively Evaluated for Impairment			282,073	243,100
Loans and leases receivable, before fees, gross			282,951	245,183
Real Estate Mortgage | Residential mortgages
Period-end amount allocated to:
Loans Individually Evaluated for Impairment			366	1,063
Loans Collectively Evaluated for Impairment			36,870	44,818
Loans and leases receivable, before fees, gross			37,236	45,881
Real Estate Mortgage | Home improvement and home equity loans
Period-end amount allocated to:
Loans Individually Evaluated for Impairment			0	0
Loans Collectively Evaluated for Impairment			107	173
Loans and leases receivable, before fees, gross			107	173
Real Estate Construction and Development
Summarizes activity in allowance for credit losses by loan category [Roll Forward]
Beginning balance	2,808	2,424
(Recovery of provision) provision for credit losses	1,235	(384)
Charge-offs	(358)	0
Recoveries	37	0
Net recoveries (charge-offs)	(321)	0
Ending balance	3,722	2,808
Period-end amount allocated to:
Loans individually evaluated for impairment			0	0
Loans collectively evaluated for impairment			3,722	2,808
Ending balance	3,722	2,424	3,722	2,808
Loans Individually Evaluated for Impairment			11,057	11,478
Loans Collectively Evaluated for Impairment			163,959	127,306
Loans and leases receivable, before fees, gross			175,016	138,784
Agricultural
Summarizes activity in allowance for credit losses by loan category [Roll Forward]
Beginning balance	761	1,131
(Recovery of provision) provision for credit losses	(50)	334
Charge-offs	0	(36)
Recoveries	0	0
Net recoveries (charge-offs)	0	(36)
Ending balance	711	761
Period-end amount allocated to:
Loans individually evaluated for impairment			196	256
Loans collectively evaluated for impairment			515	505
Ending balance	$ 761	761	711	761
Loans Individually Evaluated for Impairment			609	694
Loans Collectively Evaluated for Impairment			50,470	51,503
Loans and leases receivable, before fees, gross			51,079	52,197
Installment and Student Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Number of loan portfolio segment | segment	3
Summarizes activity in allowance for credit losses by loan category [Roll Forward]
Beginning balance	$ 2,132	1,559
(Recovery of provision) provision for credit losses	2,435	(1,163)
Charge-offs	(1,961)	(761)
Recoveries	8	171
Net recoveries (charge-offs)	(1,953)	(590)
Ending balance	2,614	2,132
Period-end amount allocated to:
Loans individually evaluated for impairment			0	0
Loans collectively evaluated for impairment			2,614	2,132
Ending balance	2,132	2,132	2,614	2,132
Loans Individually Evaluated for Impairment			0	0
Loans Collectively Evaluated for Impairment			61,508	69,878
Loans and leases receivable, before fees, gross			61,508	69,878
Unallocated
Summarizes activity in allowance for credit losses by loan category [Roll Forward]
Beginning balance	173	593
(Recovery of provision) provision for credit losses	102	420
Charge-offs	0	0
Recoveries	0	0
Net recoveries (charge-offs)	0	0
Ending balance	275	173
Period-end amount allocated to:
Loans individually evaluated for impairment			0	0
Loans collectively evaluated for impairment			275	173
Ending balance	$ 173	$ 173	$ 275	$ 173