XML 57 R47.htm IDEA: XBRL DOCUMENT
v3.23.3

Fair Value Accounting (Details) - Schedule of unobservable inputs used in the fair value measurements | 9 Months Ended
--- | ---
Sep. 30, 2023
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |
Valuation Technique | Appraised Value/ Discounted Cash Flows
Significant Unobservable Inputs | Discounts to appraisals or cash flows for estimated holding and/or selling costs or age of appraisal
Minimum [Member] |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |
Range of Inputs | 0.00%
Maximum [Member] |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |
Range of Inputs | 25.00%

X
- References No definition available. + Details
Name: | sfst_FairValueAssumptionsRangeOfInputs
Namespace Prefix: | sfst_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | sfst_FairValueOfMeasurementsSignificantAssumptions
Namespace Prefix: | sfst_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | sfst_FairValueOfMeasurementsValuationTechniques
Namespace Prefix: | sfst_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- 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
Name: | us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |