Basis of Presentation (Details)	Mar. 31, 2026
Chief Executive Officer and Chairman of the Board [Member]
Basis of Presentation [Abstract]
Ownership interest percentage	69.00%
FSBI [Member] \| FSNB [Member]
Basis of Presentation [Abstract]
Ownership in subsidiary bank	95.00%

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.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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+ Details