XML 38 R25.htm IDEA: XBRL DOCUMENT v3.23.2

Investment Securities (Details) - Schedule of gross unrealized losses on investment securities and fair market value of related securities $ in Thousands	Jun. 30, 2023 USD ($) Integer	Dec. 31, 2022 USD ($) Integer
Corporate bonds [Member]
Marketable Securities [Line Items]
Available for sale Securities, Less than 12 months, Number of investments | Investments | Integer
Available for sale Securities, Less than 12 months, Fair value
Available for sale Securities, Less than 12 months, Unrealized losses
Available for sale Securities, 12 months or longer, Number of investments | Investments | Integer	1	1
Available for sale Securities, 12 months or longer, Fair value	$ 1,874	$ 1,883
Available for sale Securities, 12 months or Longer, Unrealized losses	$ 286	$ 289
Available for sale Securities, Total, Number of investments | Investments | Integer	1	1
Available for sale Securities, Total, Fair value	$ 1,874	$ 1,883
Available for sale Securities, Total, Unrealized losses	$ 286	$ 289
US treasuries [Member]
Marketable Securities [Line Items]
Available for sale Securities, Less than 12 months, Number of investments | Investments | Integer
Available for sale Securities, Less than 12 months, Fair value
Available for sale Securities, Less than 12 months, Unrealized losses
Available for sale Securities, 12 months or longer, Number of investments | Investments | Integer	1	1
Available for sale Securities, 12 months or longer, Fair value	$ 875	$ 871
Available for sale Securities, 12 months or Longer, Unrealized losses	$ 124	$ 128
Available for sale Securities, Total, Number of investments | Investments | Integer	1	1
Available for sale Securities, Total, Fair value	$ 875	$ 871
Available for sale Securities, Total, Unrealized losses	$ 124	$ 128
US government agencies [Member]
Marketable Securities [Line Items]
Available for sale Securities, Less than 12 months, Number of investments | Investments | Integer
Available for sale Securities, Less than 12 months, Fair value
Available for sale Securities, Less than 12 months, Unrealized losses
Available for sale Securities, 12 months or longer, Number of investments | Investments | Integer	10	10
Available for sale Securities, 12 months or longer, Fair value	$ 10,810	$ 10,617
Available for sale Securities, 12 months or Longer, Unrealized losses	$ 2,199	$ 2,390
Available for sale Securities, Total, Number of investments | Investments | Integer	10	10
Available for sale Securities, Total, Fair value	$ 10,810	$ 10,617
Available for sale Securities, Total, Unrealized losses	$ 2,199	$ 2,390
State and political subdivisions [Member]
Marketable Securities [Line Items]
Available for sale Securities, Less than 12 months, Number of investments | Investments | Integer	3	10
Available for sale Securities, Less than 12 months, Fair value	$ 1,216	$ 5,101
Available for sale Securities, Less than 12 months, Unrealized losses	$ 24	$ 763
Available for sale Securities, 12 months or longer, Number of investments | Investments | Integer	29	22
Available for sale Securities, 12 months or longer, Fair value	$ 18,123	$ 13,805
Available for sale Securities, 12 months or Longer, Unrealized losses	$ 3,411	$ 3,241
Available for sale Securities, Total, Number of investments | Investments | Integer	32	32
Available for sale Securities, Total, Fair value	$ 19,339	$ 18,906
Available for sale Securities, Total, Unrealized losses	$ 3,435	$ 4,004
Asset-backed securities [Member]
Marketable Securities [Line Items]
Available for sale Securities, Less than 12 months, Number of investments | Investments | Integer	1	5
Available for sale Securities, Less than 12 months, Fair value	$ 393	$ 4,291
Available for sale Securities, Less than 12 months, Unrealized losses	$ 1	$ 135
Available for sale Securities, 12 months or longer, Number of investments | Investments | Integer	7	3
Available for sale Securities, 12 months or longer, Fair value	$ 5,175	$ 1,938
Available for sale Securities, 12 months or Longer, Unrealized losses	$ 128	$ 71
Available for sale Securities, Total, Number of investments | Investments | Integer	8	8
Available for sale Securities, Total, Fair value	$ 5,568	$ 6,229
Available for sale Securities, Total, Unrealized losses	$ 129	$ 206
Mortgage-backed securities [Member] | FHLMC [Member]
Marketable Securities [Line Items]
Available for sale Securities, Less than 12 months, Number of investments | Investments | Integer	2	4
Available for sale Securities, Less than 12 months, Fair value	$ 2,863	$ 3,712
Available for sale Securities, Less than 12 months, Unrealized losses	$ 62	$ 155
Available for sale Securities, 12 months or longer, Number of investments | Investments | Integer	26	17
Available for sale Securities, 12 months or longer, Fair value	$ 17,035	$ 16,629
Available for sale Securities, 12 months or Longer, Unrealized losses	$ 3,668	$ 3,590
Available for sale Securities, Total, Number of investments | Investments | Integer	28	21
Available for sale Securities, Total, Fair value	$ 19,898	$ 20,341
Available for sale Securities, Total, Unrealized losses	$ 3,730	$ 3,745
Mortgage-backed securities [Member] | FNMA [Member]
Marketable Securities [Line Items]
Available for sale Securities, Less than 12 months, Number of investments | Investments | Integer	1	9
Available for sale Securities, Less than 12 months, Fair value	$ 5	$ 2,208
Available for sale Securities, Less than 12 months, Unrealized losses	$ 1	$ 201
Available for sale Securities, 12 months or longer, Number of investments | Investments | Integer	29	28
Available for sale Securities, 12 months or longer, Fair value	$ 28,606	$ 27,413
Available for sale Securities, 12 months or Longer, Unrealized losses	5,416	5,319
Available for sale Securities, Total, Fair value	28,611	29,621
Available for sale Securities, Total, Unrealized losses	$ 5,417	$ 5,520
Available for sale Securities, Total, Number of investments | Investments | Integer	30	37
Mortgage-backed securities [Member] | GNMA [Member]
Marketable Securities [Line Items]
Available for sale Securities, Less than 12 months, Number of investments | Investments | Integer		1
Available for sale Securities, Less than 12 months, Fair value		$ 103
Available for sale Securities, Less than 12 months, Unrealized losses		$ 7
Available for sale Securities, 12 months or longer, Number of investments | Investments | Integer	7	6
Available for sale Securities, 12 months or longer, Fair value	$ 4,573	$ 4,776
Available for sale Securities, 12 months or Longer, Unrealized losses	$ 768	$ 687
Available for sale Securities, Total, Number of investments | Investments | Integer	7	7
Available for sale Securities, Total, Fair value	$ 4,573	$ 4,879
Available for sale Securities, Total, Unrealized losses	$ 768	$ 694
Total investment securities [Member]
Marketable Securities [Line Items]
Available for sale Securities, Less than 12 months, Number of investments | Investments | Integer	7	29
Available for sale Securities, Less than 12 months, Fair value	$ 4,477	$ 15,415
Available for sale Securities, Less than 12 months, Unrealized losses	$ 88	$ 1,261
Available for sale Securities, 12 months or longer, Number of investments | Investments | Integer	110	88
Available for sale Securities, 12 months or longer, Fair value	$ 87,071	$ 77,932
Available for sale Securities, 12 months or Longer, Unrealized losses	16,000	15,715
Available for sale Securities, Total, Fair value	91,548	93,347
Available for sale Securities, Total, Unrealized losses	$ 16,088	$ 16,976
Available for sale Securities, Total, Number of investments | Investments | Integer	117	117

X

- Definition

Number of investments in continuous unrealized loss position.

+ References

No definition available.

+ Details

Name:	sfst_AvailableForSaleSecuritiesTotalNumberOfInvestments
Namespace Prefix:	sfst_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Number of investments in continuous unrealized loss position.

+ References

No definition available.

+ Details

Name:	sfst_NumberOfInvestmentsInContinuousUnrealizedLossPosition
Namespace Prefix:	sfst_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Number of investments in continuous unrealized loss position, less than twelve months.

+ References

No definition available.

+ Details

Name:	sfst_NumberOfInvestmentsInContinuousUnrealizedLossPositionLessThanTwelveMonths
Namespace Prefix:	sfst_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Number of investments in continuous unrealized loss position twelve months or longer.

+ References

No definition available.

+ Details

Name:	sfst_NumberOfInvestmentsInContinuousUnrealizedLossPositionTwelveMonthsOrLonger
Namespace Prefix:	sfst_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479081/326-30-55-8

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-7

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-5

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-5

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479081/326-30-55-8

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-7

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-5

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-5

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479081/326-30-55-8

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-6

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-4

+ Details

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

X

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-6

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-4

+ Details

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

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_MarketableSecuritiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=sfst_CorporateBondsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=sfst_USTreasuresMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_AgencySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_FederalHomeLoanMortgageCorporationCertificatesAndObligationsFHLMCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_FederalNationalMortgageAssociationCertificatesAndObligationsFNMAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_GovernmentNationalMortgageAssociationCertificatesAndObligationsGNMAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=sfst_TotalInvestmentSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: