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Financial Instruments with Off Balance Sheet Risk - Narrative (Details) - USD ($) $ in Thousands | Sep. 30, 2021 | Dec. 31, 2020
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Letter of credit with FHLB |  |
Financial Instruments with Off Balance Sheet Risk |  |
Outstanding letters of credit | $ 150 | $ 150
Letter of credit with Bank of North Dakota |  |
Financial Instruments with Off Balance Sheet Risk |  |
Outstanding letters of credit | 0 | 0
Collateralized loans | $ 230,200 | $ 245,700

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- Definition Amount of assets pledged to secure a debt instrument. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 3 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823 + Details
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Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Definition 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. + References No definition available. + Details
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- Definition The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- Details
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- Details
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