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v3.22.4

Description Of Business - Additional Information (Details) - Branch |  | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 03, 2021 | Sep. 30, 2021 | Dec. 31, 2022
Organization Consolidation And Presentation Of Financial Statements [Line Items] |  |  |
Number of states |  |  | 12
ALC [Member] |  |  |
Organization Consolidation And Presentation Of Financial Statements [Line Items] |  |  |
Number of office closed | 20 | 20 |

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- Definition Number of states conducting lending of loan portfolio. + References No definition available. + Details
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- Definition Organization consolidation and presentation of financial statements. + References No definition available. + Details
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- Definition Represents number of office closed during period for restructuring and related cost. + References No definition available. + Details
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Namespace Prefix: | fusb_
Data Type: | xbrli:integerItemType
Balance Type: | na
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- Details
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Namespace Prefix: |
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