XML 38 R27.htm IDEA: XBRL DOCUMENT
v3.19.1

Investment Securities (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2019 | Dec. 31, 2018
Available for sale |  |
Total investment securities available for sale, Amortized Cost | $ 73,780 | $ 76,065
Total investment securities available for sale, Gross Unrealized Gains | 323 | 174
Total investment securities available for sale, Gross Unrealized Losses | 803 | 1,334
Available-for-sale securities, investment securities, Fair Value | 73,300 | 74,905
US government agencies [Member] |  |
Available for sale |  |
Total investment securities available for sale, Amortized Cost | 8,970 | 8,975
Total investment securities available for sale, Gross Unrealized Gains | 1 | 1
Total investment securities available for sale, Gross Unrealized Losses | 75 | 194
Available-for-sale securities, investment securities, Fair Value | 8,896 | 8,782
SBA securities [Member] |  |
Available for sale |  |
Total investment securities available for sale, Amortized Cost | 3,441 | 3,628
Total investment securities available for sale, Gross Unrealized Gains |  |
Total investment securities available for sale, Gross Unrealized Losses | 52 | 103
Available-for-sale securities, investment securities, Fair Value | 3,389 | 3,525
State and political subdivisions [Member] |  |
Available for sale |  |
Total investment securities available for sale, Amortized Cost | 8,061 | 8,371
Total investment securities available for sale, Gross Unrealized Gains | 127 | 48
Total investment securities available for sale, Gross Unrealized Losses | 13 | 63
Available-for-sale securities, investment securities, Fair Value | 8,175 | 8,356
Asset-backed securities [Member] |  |
Available for sale |  |
Total investment securities available for sale, Amortized Cost | 9,504 | 9,595
Total investment securities available for sale, Gross Unrealized Gains |  | 12
Total investment securities available for sale, Gross Unrealized Losses | 78 | 49
Available-for-sale securities, investment securities, Fair Value | 9,426 | 9,558
Mortgage-backed securities [Member] |  |
Available for sale |  |
Total investment securities available for sale, Amortized Cost | 43,804 | 45,496
Total investment securities available for sale, Gross Unrealized Gains | 195 | 113
Total investment securities available for sale, Gross Unrealized Losses | 585 | 925
Available-for-sale securities, investment securities, Fair Value | 43,414 | 44,684
Mortgage-backed securities [Member] | FHLMC [Member] |  |
Available for sale |  |
Total investment securities available for sale, Amortized Cost | 11,873 | 12,258
Total investment securities available for sale, Gross Unrealized Gains | 147 | 87
Total investment securities available for sale, Gross Unrealized Losses | 135 | 242
Available-for-sale securities, investment securities, Fair Value | 11,885 | 12,103
Mortgage-backed securities [Member] | FNMA [Member] |  |
Available for sale |  |
Total investment securities available for sale, Amortized Cost | 27,777 | 29,068
Total investment securities available for sale, Gross Unrealized Gains | 45 | 25
Total investment securities available for sale, Gross Unrealized Losses | 364 | 551
Available-for-sale securities, investment securities, Fair Value | 27,458 | 28,542
Mortgage-backed securities [Member] | GNMA [Member] |  |
Available for sale |  |
Total investment securities available for sale, Amortized Cost | 4,154 | 4,170
Total investment securities available for sale, Gross Unrealized Gains | 3 | 1
Total investment securities available for sale, Gross Unrealized Losses | 86 | 132
Available-for-sale securities, investment securities, Fair Value | $ 4,071 | $ 4,039

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

X
- Definition This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesAmortizedCost
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). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26610-111562 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of unrealized gain before deducting unrealized loss on investments in debt and equity securities classified as available-for-sale securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of unrealized loss before deducting unrealized gain on investments in available-for-sale securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=sfst_SbaSecuritiesMember
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_MortgageBackedSecuritiesMember
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: |