Loans and Allowance for Loan Losses - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 15,821	$ 15,767
Provision (reversal)	900	0
Charge-offs	(78)	(5)
Recoveries	34	59
Ending balance	16,677	15,821
Ending ALLL related to loans collectively evaluated for impairment	16,280	15,043
Ending ALLL related to loans individually evaluated for impairment	397	778
Ending ALLL related to purchased credit-impaired loans	16,677	15,821
Recorded Investment:
Collectively evaluated for impairment	1,829,737	1,746,714
Individually evaluated for impairment	11,500	15,038
Total loans	$ 1,843,286	$ 1,763,864
Ratio of allowance for loan losses to total loans	0.90%	0.90%
Allowance for loan losses to non-accrual loans	7379.00%	2270.00%
Purchased credit-impaired
Allowance for Loan and Lease Losses [Roll Forward]
Ending ALLL related to purchased credit-impaired loans	$ 0	$ 0
Recorded Investment:
Purchased credit-impaired	2,049	2,112
Commercial \| Commercial and industrial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,436	3,654
Provision (reversal)	(49)	(1,232)
Charge-offs	(75)	(3)
Recoveries	22	17
Ending balance	2,334	2,436
Ending ALLL related to loans collectively evaluated for impairment	2,231	1,970
Ending ALLL related to loans individually evaluated for impairment	103	466
Ending ALLL related to purchased credit-impaired loans	2,334	2,436
Recorded Investment:
Collectively evaluated for impairment	245,460	228,883
Individually evaluated for impairment	1,223	1,825
Total loans	$ 246,687	$ 230,739
Ratio of allowance for loan losses to total loans	0.95%	1.06%
Commercial \| Commercial and industrial \| Purchased credit-impaired
Allowance for Loan and Lease Losses [Roll Forward]
Ending ALLL related to purchased credit-impaired loans	$ 0	$ 0
Recorded Investment:
Purchased credit-impaired	4	31
Commercial real estate \| Commercial real estate, owner-occupied
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,407	2,294
Provision (reversal)	55	113
Charge-offs	0	0
Recoveries	0	0
Ending balance	2,462	2,407
Ending ALLL related to loans collectively evaluated for impairment	2,267	2,218
Ending ALLL related to loans individually evaluated for impairment	195	189
Ending ALLL related to purchased credit-impaired loans	2,462	2,407
Recorded Investment:
Collectively evaluated for impairment	300,685	305,097
Individually evaluated for impairment	6,998	6,993
Total loans	$ 308,824	$ 313,277
Ratio of allowance for loan losses to total loans	0.80%	0.77%
Commercial real estate \| Commercial real estate, owner-occupied \| Purchased credit-impaired
Allowance for Loan and Lease Losses [Roll Forward]
Ending ALLL related to purchased credit-impaired loans	$ 0	$ 0
Recorded Investment:
Purchased credit-impaired	1,141	1,187
Commercial real estate \| Commercial real estate, investor
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	7,703	6,475
Provision (reversal)	768	1,228
Charge-offs	0	0
Recoveries	12	0
Ending balance	8,483	7,703
Ending ALLL related to loans collectively evaluated for impairment	8,442	7,658
Ending ALLL related to loans individually evaluated for impairment	41	45
Ending ALLL related to purchased credit-impaired loans	8,483	7,703
Recorded Investment:
Collectively evaluated for impairment	943,714	870,778
Individually evaluated for impairment	1,770	1,821
Total loans	$ 946,317	$ 873,410
Ratio of allowance for loan losses to total loans	0.90%	0.88%
Commercial real estate \| Commercial real estate, investor \| Purchased credit-impaired
Allowance for Loan and Lease Losses [Roll Forward]
Ending ALLL related to purchased credit-impaired loans	$ 0	$ 0
Recorded Investment:
Purchased credit-impaired	833	811
Commercial real estate \| Construction
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	756	681
Provision (reversal)	(118)	75
Charge-offs	0	0
Recoveries	0	0
Ending balance	638	756
Ending ALLL related to loans collectively evaluated for impairment	638	756
Ending ALLL related to loans individually evaluated for impairment	0	0
Ending ALLL related to purchased credit-impaired loans	638	756
Recorded Investment:
Collectively evaluated for impairment	61,095	73,735
Individually evaluated for impairment	0	2,688
Total loans	$ 61,095	$ 76,423
Ratio of allowance for loan losses to total loans	1.04%	0.99%
Commercial real estate \| Construction \| Purchased credit-impaired
Allowance for Loan and Lease Losses [Roll Forward]
Ending ALLL related to purchased credit-impaired loans	$ 0	$ 0
Recorded Investment:
Purchased credit-impaired	0	0
Residential loans \| Home equity
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	915	1,031
Provision (reversal)	(65)	(116)
Charge-offs	0	0
Recoveries	0	0
Ending balance	850	915
Ending ALLL related to loans collectively evaluated for impairment	845	910
Ending ALLL related to loans individually evaluated for impairment	5	5
Ending ALLL related to purchased credit-impaired loans	850	915
Recorded Investment:
Collectively evaluated for impairment	115,535	124,049
Individually evaluated for impairment	418	564
Total loans	$ 116,024	$ 124,696
Ratio of allowance for loan losses to total loans	0.73%	0.73%
Allowance for loan losses to non-accrual loans	506.00%	292.00%
Residential loans \| Home equity \| Purchased credit-impaired
Allowance for Loan and Lease Losses [Roll Forward]
Ending ALLL related to purchased credit-impaired loans	$ 0	$ 0
Recorded Investment:
Purchased credit-impaired	71	83
Residential loans \| Other residential
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	800	536
Provision (reversal)	173	264
Charge-offs	0	0
Recoveries	0	0
Ending balance	973	800
Ending ALLL related to loans collectively evaluated for impairment	973	800
Ending ALLL related to loans individually evaluated for impairment	0	0
Ending ALLL related to purchased credit-impaired loans	973	800
Recorded Investment:
Collectively evaluated for impairment	136,205	117,385
Individually evaluated for impairment	452	462
Total loans	$ 136,657	$ 117,847
Ratio of allowance for loan losses to total loans	0.71%	0.68%
Residential loans \| Other residential \| Purchased credit-impaired
Allowance for Loan and Lease Losses [Roll Forward]
Ending ALLL related to purchased credit-impaired loans	$ 0	$ 0
Recorded Investment:
Purchased credit-impaired	0	0
Consumer loans \| Installment and other consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	310	378
Provision (reversal)	(23)	(108)
Charge-offs	(3)	(2)
Recoveries	0	42
Ending balance	284	310
Ending ALLL related to loans collectively evaluated for impairment	231	237
Ending ALLL related to loans individually evaluated for impairment	53	73
Ending ALLL related to purchased credit-impaired loans	284	310
Recorded Investment:
Collectively evaluated for impairment	27,043	26,787
Individually evaluated for impairment	639	685
Total loans	$ 27,682	$ 27,472
Ratio of allowance for loan losses to total loans	1.03%	1.13%
Consumer loans \| Installment and other consumer \| Purchased credit-impaired
Allowance for Loan and Lease Losses [Roll Forward]
Ending ALLL related to purchased credit-impaired loans	$ 0	$ 0
Recorded Investment:
Purchased credit-impaired	0	0
Unallocated
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	494	718
Provision (reversal)	159	(224)
Charge-offs	0	0
Recoveries	0	0
Ending balance	653	494
Ending ALLL related to loans collectively evaluated for impairment	653	494
Ending ALLL related to loans individually evaluated for impairment	0	0
Ending ALLL related to purchased credit-impaired loans	653	494
Recorded Investment:
Collectively evaluated for impairment	0	0
Individually evaluated for impairment	0	0
Total loans	0	0
Unallocated \| Purchased credit-impaired
Allowance for Loan and Lease Losses [Roll Forward]
Ending ALLL related to purchased credit-impaired loans	0	0
Recorded Investment:
Purchased credit-impaired	$ 0	$ 0

Allowance as percentage of non-accrual loans.

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Allowance as percentage of total loans.

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Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount of expense related to estimated loss from loan and lease transactions.

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