Loans - Allowance for Credit Losses by Loan Category (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) loan segment	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 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	$ 8,862	$ 8,452	$ 7,908	$ 8,395
Provision (recovery of provision) for credit losses	4	5	2,138	15
Charge-offs	(284)	(299)	(1,492)	(418)
Recoveries	126	72	154	238
Net recoveries (charge-offs)	(158)	(227)	(1,338)	(180)
Ending balance	8,708	8,230	8,708	8,230
Period-end amount allocated to:
Loans individually evaluated for impairment					$ 402		$ 1,142
Loans collectively evaluated for impairment					8,306		7,088
Ending balance	8,708	8,230	8,708	8,230	8,708	$ 7,908	8,230
Loans Individually Evaluated for Impairment					15,059		18,362
Loans Collectively Evaluated for Impairment					646,423		551,766
Total Loans					661,482	597,374	570,128
Commercial and Industrial
Summarizes activity in allowance for credit losses by loan category [Roll Forward]
Beginning balance	756	1,457	1,322	1,673
Provision (recovery of provision) for credit losses	(46)	(168)	(625)	(441)
Charge-offs	0	0	0	0
Recoveries	9	7	22	64
Net recoveries (charge-offs)	9	7	22	64
Ending balance	719	1,296	719	1,296
Period-end amount allocated to:
Loans individually evaluated for impairment					0		525
Loans collectively evaluated for impairment					719		771
Ending balance	719	1,296	$ 719	1,296	719	1,322	1,296
Loans Individually Evaluated for Impairment					494		1,918
Loans Collectively Evaluated for Impairment					65,248		46,219
Total Loans					65,742	45,278	48,137
Commercial and Industrial | Commercial and business loans
Period-end amount allocated to:
Loans Individually Evaluated for Impairment					274		1,652
Loans Collectively Evaluated for Impairment					38,944		45,703
Total Loans					39,218	44,534	47,355
Commercial and Industrial | Government program loans
Period-end amount allocated to:
Loans Individually Evaluated for Impairment					220		266
Loans Collectively Evaluated for Impairment					26,304		516
Total Loans					26,524	744	782
Real Estate Mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Number of segments | segment			3
Summarizes activity in allowance for credit losses by loan category [Roll Forward]
Beginning balance	812	864	$ 712	1,015
Provision (recovery of provision) for credit losses	(147)	(109)	(56)	(263)
Charge-offs	0	0	0	(5)
Recoveries	79	52	88	60
Net recoveries (charge-offs)	79	52	88	55
Ending balance	744	807	744	807
Period-end amount allocated to:
Loans individually evaluated for impairment					187		361
Loans collectively evaluated for impairment					557		446
Ending balance	744	807	744	807	744	712	807
Loans Individually Evaluated for Impairment					2,851		4,179
Loans Collectively Evaluated for Impairment					306,998		271,780
Total Loans					309,849	291,237	275,959
Real Estate Mortgage | Commercial real estate
Period-end amount allocated to:
Loans Individually Evaluated for Impairment					2,036		3,105
Loans Collectively Evaluated for Impairment					261,977		221,608
Total Loans					264,013	245,183	224,713
Real Estate Mortgage | Residential mortgages
Period-end amount allocated to:
Loans Individually Evaluated for Impairment					815		1,074
Loans Collectively Evaluated for Impairment					44,907		49,988
Total Loans					45,722	45,881	51,062
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					114		184
Total Loans					114	173	184
Real estate construction and development
Summarizes activity in allowance for credit losses by loan category [Roll Forward]
Beginning balance	3,572	2,330	2,808	2,424
Provision (recovery of provision) for credit losses	439	(3)	1,455	(97)
Charge-offs	(106)	0	(358)	0
Recoveries	37	0	37	0
Net recoveries (charge-offs)	(69)	0	(321)	0
Ending balance	3,942	2,327	3,942	2,327
Period-end amount allocated to:
Loans individually evaluated for impairment					0		0
Loans collectively evaluated for impairment					3,942		2,327
Ending balance	3,942	2,327	2,808	2,327	3,942	2,808	2,327
Loans Individually Evaluated for Impairment					11,058		11,529
Loans Collectively Evaluated for Impairment					160,831		104,914
Total Loans					171,889	138,784	116,443
Agricultural
Summarizes activity in allowance for credit losses by loan category [Roll Forward]
Beginning balance	836	1,132	761	1,131
Provision (recovery of provision) for credit losses	(68)	(227)	7	(226)
Charge-offs	0	(36)	0	(36)
Recoveries	0	0	0	0
Net recoveries (charge-offs)	0	(36)	0	(36)
Ending balance	768	869	768	869
Period-end amount allocated to:
Loans individually evaluated for impairment					215		256
Loans collectively evaluated for impairment					553		613
Ending balance	768	869	761	869	768	761	869
Loans Individually Evaluated for Impairment					656		736
Loans Collectively Evaluated for Impairment					50,931		59,364
Total Loans					51,587	52,197	60,100
Consumer
Summarizes activity in allowance for credit losses by loan category [Roll Forward]
Beginning balance	2,746	1,991	2,132	1,559
Provision (recovery of provision) for credit losses	(749)	388	815	833
Charge-offs	(178)	(263)	(1,134)	(377)
Recoveries	1	13	7	114
Net recoveries (charge-offs)	(177)	(250)	(1,127)	(263)
Ending balance	1,820	2,129	1,820	2,129
Period-end amount allocated to:
Loans individually evaluated for impairment					0		0
Loans collectively evaluated for impairment					1,820		2,129
Ending balance	1,820	2,129	1,820	2,129	1,820	2,132	2,129
Loans Individually Evaluated for Impairment					0		0
Loans Collectively Evaluated for Impairment					62,415		69,489
Total Loans					62,415	69,878	69,489
Unallocated
Summarizes activity in allowance for credit losses by loan category [Roll Forward]
Beginning balance	140	678	173	593
Provision (recovery of provision) for credit losses	575	124	542	209
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Net recoveries (charge-offs)	0	0	0	0
Ending balance	715	802	715	802
Period-end amount allocated to:
Loans individually evaluated for impairment					0		0
Loans collectively evaluated for impairment					715		802
Ending balance	$ 715	$ 802	$ 173	$ 802	$ 715	$ 173	$ 802