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Investment Securities (Details Narrative) | Sep. 30, 2023 Integer
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Investments, Debt and Equity Securities [Abstract] |
Fair market value, less than 12 months, number of investments | 122

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- Definition Number of investments in continuous unrealized loss position, less than twelve month. + References No definition available. + Details
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Namespace Prefix: | sfst_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

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- References No definition available. + Details
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Namespace Prefix: | us-gaap_
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Balance Type: | na
Period Type: | duration