XML 40 R29.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Investment Securities (Details Textual) $ in Thousands | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2017 USD ($) Investment | Sep. 30, 2016 USD ($) | Sep. 30, 2017 USD ($) Investment | Sep. 30, 2016 USD ($) | Dec. 31, 2016 USD ($) Investment
Investment Securities (Textual) |  |  |  |  |
Sale of investment securities |  |  | $ 915 | $ 33,500 |
Gain on sale of investment securities |  | $ 106 | 2 | $ 431 |
Fair market value, less than 12 months | 41,200 |  | 41,200 |  |
Fair market value, 12 months or longer | 14,900 |  | 14,900 |  |
Securities pledged as collateral for repurchase agreements from brokers | $ 9,800 |  | $ 9,800 |  | $ 21,000
Securities pledged to secure client deposit |  |  |  |  | $ 21,100
Number of investments, less than 12 months | Investment | 40 |  | 40 |  | 63
Number of investments, 12 months or longer | Investment | 16 |  | 16 |  | 2

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

X
- Definition Investments with a fair market value in continuous unrealized loss position for less than twelve months. + References No definition available. + Details
Name: | sfst_InvestmentsWithFairMarketValueInContinuousUnrealizedLossPositionLessThanTwelveMonths
Namespace Prefix: | sfst_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Investments with a fair market value In continuous unrealized loss position twelve months or longer. + References No definition available. + Details
Name: | sfst_InvestmentsWithFairMarketValueInContinuousUnrealizedLossPositionLessThanTwelveMonthsOrLonger
Namespace Prefix: | sfst_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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 Securities pledged to secure client deposit. + References No definition available. + Details
Name: | sfst_SecuritiesPledgedToSecureClientDeposit
Namespace Prefix: | sfst_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The fair value of available-for-sale securities that serve as collateral for borrowings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5086-111524 + Details
Name: | us-gaap_AvailableForSaleSecuritiesPledgedAsCollateral
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The difference between the carrying value and the sale price of an investment. A gain would be recognized when the sale price of the investment is greater than the carrying value of the investment. This element refers to the Gain included in earnings and not to the cash proceeds of the sale. + References No definition available. + Details
Name: | us-gaap_GainOnSaleOfInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash inflow associated with the sale of debt securities classified as available-for-sale securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26853-111562 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration