XML 51 R40.htm IDEA: XBRL DOCUMENT v3.23.1

Derivative Financial Instruments (Details) - Schedule of outstanding financial derivative instruments - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Mortgage loan interest rate lock commitments [Member]
Derivative Financial Instruments (Details) - Schedule of outstanding financial derivative instruments [Line Items]
Derivative financial instruments, notional amount	$ 13,384	$ 6,793
Balance Sheet Location, description	Other assets	Other assets
Derivative Asset/(Liability), Fair Value	$ 187	$ 49
MBS forward sales commitments [Member]
Derivative Financial Instruments (Details) - Schedule of outstanding financial derivative instruments [Line Items]
Derivative financial instruments, notional amount	$ 10,000	$ 5,750
Balance Sheet Location, description	Other liabilities	Other assets
Derivative Asset/(Liability), Fair Value	$ (86)	$ 27
Total derivative financial instruments [Member]
Derivative Financial Instruments (Details) - Schedule of outstanding financial derivative instruments [Line Items]
Derivative financial instruments, notional amount	23,384	12,543
Derivative Asset/(Liability), Fair Value	$ 101	$ 76

X

- Definition

Description of balance sheet location.

+ References

No definition available.

+ Details

Name:	sfst_BalanceSheetLocationDescription
Namespace Prefix:	sfst_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- References

No definition available.

+ Details

Name:	sfst_DerivativeFinancialInstrumentsDetailsScheduleofoutstandingfinancialderivativeinstrumentsLineItems
Namespace Prefix:	sfst_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 5
-SubTopic 10
-Topic 815
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480463/815-10-45-5

+ Details

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

X

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-1B

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-1A

+ Details

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

X

- Details

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

X

- Details

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

X

- Details

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