Loans and Allowance for Credit Losses - Amortized Cost and Unpaid Principal of Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 30, 2021	Jan. 01, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans	$ 1,450,657			$ 1,444,050
Allowance for credit losses	(13,816)	$ (14,539)		(21,136)	$ (21,683)	$ (20,653)	$ (19,088)
Net loans	1,436,841			1,422,914
Unpaid Principal	1,465,528			1,455,830
Difference	(14,871)			(11,780)
Cumulative effect, period of adoption, adjusted balance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses			$ (16,600)
Commercial & industrial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans	504,305			772,468
Allowance for credit losses	(3,982)	(4,291)		(7,973)	(8,195)	(7,366)	(6,604)
Unpaid Principal	513,482
Difference	(9,177)
Commercial & industrial loans | Cumulative effect, period of adoption, adjusted balance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans				612,254
Unpaid Principal				619,304
Difference				(7,050)
Commercial real estate | Owner occupied properties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans	292,021
Allowance for credit losses	(3,493)	(3,340)
Unpaid Principal	293,346
Difference	(1,325)
Commercial real estate | Owner occupied properties | Cumulative effect, period of adoption, adjusted balance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans				233,320
Unpaid Principal				234,363
Difference				(1,043)
Commercial real estate | Non-owner occupied and multifamily properties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans	443,258
Allowance for credit losses	(3,876)	(3,841)
Unpaid Principal	446,688
Difference	(3,430)
Commercial real estate | Non-owner occupied and multifamily properties | Cumulative effect, period of adoption, adjusted balance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans				392,452
Unpaid Principal				394,860
Difference				(2,408)
Residential | 1-4 family residential properties secured by first liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans	29,548
Allowance for credit losses	(476)	(630)
Unpaid Principal	29,627
Difference	(79)
Residential | 1-4 family residential properties secured by first liens | Cumulative effect, period of adoption, adjusted balance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans				33,415
Unpaid Principal				33,510
Difference				(95)
Residential | 1-4 family residential properties secured by junior liens and revolving secured by 1-4 family first liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans	18,749
Allowance for credit losses	(307)	(340)
Unpaid Principal	18,626
Difference	123
Residential | 1-4 family residential properties secured by junior liens and revolving secured by 1-4 family first liens | Cumulative effect, period of adoption, adjusted balance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans				18,236
Unpaid Principal				18,114
Difference				122
Residential | 1-4 family residential construction loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans	36,386
Allowance for credit losses	(184)	(231)
Unpaid Principal	36,591
Difference	(205)
Residential | 1-4 family residential construction loans | Cumulative effect, period of adoption, adjusted balance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans				32,500
Unpaid Principal				32,760
Difference				(260)
Other construction, land development and raw land loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans	73,313
Allowance for credit losses	(1,279)	(1,670)
Unpaid Principal	73,832
Difference	(519)
Other construction, land development and raw land loans | Cumulative effect, period of adoption, adjusted balance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans				83,463
Unpaid Principal				84,351
Difference				(888)
Obligations of states and political subdivisions in the US
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans	17,470
Allowance for credit losses	(36)	(39)
Unpaid Principal	17,636
Difference	(166)
Obligations of states and political subdivisions in the US | Cumulative effect, period of adoption, adjusted balance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans				15,318
Unpaid Principal				15,274
Difference				44
Agricultural production, including commercial fishing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans	27,573
Allowance for credit losses	(94)	(57)
Unpaid Principal	27,692
Difference	(119)
Agricultural production, including commercial fishing | Cumulative effect, period of adoption, adjusted balance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans				12,968
Unpaid Principal				13,093
Difference				(125)
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans	5,014
Allowance for credit losses	(83)	(94)
Unpaid Principal	4,973
Difference	41
Consumer | Cumulative effect, period of adoption, adjusted balance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans				5,734
Unpaid Principal				5,794
Difference				(60)
Other loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans	3,020			0
Allowance for credit losses	(6)	$ (6)		(2,107)	$ (2,107)	$ (2,021)	$ (2,079)
Unpaid Principal	3,035
Difference	$ (15)
Other loans | Cumulative effect, period of adoption, adjusted balance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total portfolio loans				4,390
Unpaid Principal				4,407
Difference				$ (17)