Loans and Credit Quality - Narrative (Details)		12 Months Ended
Apr. 01, 2014 USD ($) purchased_loan	Dec. 31, 2019 USD ($) financing_commitment contract	Dec. 31, 2018 USD ($) contract	Dec. 31, 2017 USD ($) contract
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans secured by real estate		70.00%
Loans unsecured		3.00%
Loans secured for general commercial uses		27.00%
Net nonaccrual loans		$ 13,951,000	$ 14,694,000
Interest income earned on nonaccrual loans		1,300,000	1,300,000	$ 1,400,000
Interest income earned on nonaccrual loans with no balance		301,000	159,000	120,000
Greater than 90 days still accruing		0	0
Recorded investment in loans considered to be impaired		24,673,000	31,714,000
Impaired loan, average recorded investment		28,395,000	34,689,000	36,900,000
Impaired loan, interest income on accrual method		623,000	847,000	$ 983,000
Loans classified as troubled debt restructuring		$ 10,106,000	14,800,000
Commitment to Lend \| financing_commitment		0
Write down on TDR		$ 64,000	$ 1,300,000
TDR with specific impairment \| contract		0	1
Number of Contracts \| contract		0	6	0
Unfunded loan commitments		$ 15,000	$ 15,000
Loans pledged as collateral		0	0
Alaska Pacific Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased impaired loans \| purchased_loan	18
Accretable difference on purchased loans	$ 0
Fair value of purchased credit impaired loans	$ 3,900,000	$ 201,000	$ 235,000
Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recovery time for market		18 months
Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recovery time for market		24 months

Financing Receivable, Acquired with Deteriorated Credit Quality, Number of Loans

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Financing Receivable, Modifications, Number of Commitments to Extend Financing

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Financing Receivable, Modifications with Specific Allowance, Number of Contracts

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Financing Receivable Recorded Investment Interest Income Earned On Nonaccrual Loans

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Financing Receivable, Recorded Investment, Nonaccrual Status, Excluding Government Guaranteed Payments

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Financing Receivables Percentage Of Total Loans Secured By Real Estate

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Financing Receivables Percentage Of Total Loans Secured For General Commercial Uses

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Financing Receivables Percentage Of Total Loans Unsecured

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Financing receivables unfunded loan commitments to directors and officers.

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Interest Income Earned on Nonaccrual Loans With No Balance

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Recovery Time of Market

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

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Fair value at acquisition of acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

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Amount of financing receivable modified as troubled debt restructuring.

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Number of financing receivable contracts modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

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Amount of financing receivable 90 days or more past due and still accruing.

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Reflects the amount of the write-down related to a troubled debt restructuring.

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

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Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

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Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

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Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered.

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