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The amount of mortgage loan interest rate lock commitments.

No definition available.

Name:	sfst_MortgageLoanInterestRateLockCommitments
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- References

No definition available.

Name:	sfst_SecuritiesAvailableForSaleAbstract
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- References

No definition available.

Name:	sfst_SecuritiesAvailableForSaleAbstract0
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Securities Available for Sale, Fair value, SBA Securities.

No definition available.

Name:	sfst_SecuritiesAvailableForSaleFairValueSbaSecurities
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Securities Available for Sale, Fair value, State and political subdivisions.

No definition available.

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Corporate bonds.

No definition available.

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Securities Available for Sale, Fair value, US agency securities.

No definition available.

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US treasuries.

No definition available.

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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258

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Fair value of obligations incurred from short sales.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 940
-SubTopic 320
-Section 35
-Paragraph 1
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=35711043&loc=d3e42429-110968

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Fair value of financial and nonfinancial obligations.

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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

No definition available.

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Fair value of securitized, pay-through debt securities collateralized by real estate mortgage loans classified as available-for-sale.

No definition available.

Name:	us-gaap_MortgageBackedSecuritiesAvailableForSaleFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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