XML 65 R52.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Summary of Significant Accounting Policies and Activities (Details) - USD ($) | 1 Months Ended |  |
--- | --- | --- | ---
Dec. 22, 2017 | Dec. 31, 2017 | Dec. 31, 2016
Summary of Significant Accounting Policies and Activities (Textual) |  |  |
Real estate loan percentage of total loan |  | 82.10% | 81.10%
Cash and cash equivalents |  | $ 7,300,000 | $ 5,000,000
Investment in trusts |  | 403,000 |
Description of tax | The legislation significantly changes U.S. tax law by, among other things, lowering corporate income tax rates from a maximum of 35% to a flat 21% rate, effective January 1, 2018. |  |
Future minimum lease payments |  | $ 13,800,000 |

X
- Definition Description of income tax. + References No definition available. + Details
Name: | sfst_IncomeTaxDescription
Namespace Prefix: | sfst_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Investment in trusts. + References No definition available. + Details
Name: | sfst_InvestmentInTrusts
Namespace Prefix: | sfst_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Real estate loan percentage of aggregate loan. + References No definition available. + Details
Name: | sfst_RealEstateLoanPercentageOfAggregateLoan
Namespace Prefix: | sfst_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Summary of significant accounting policies and activities. + References No definition available. + Details
Name: | sfst_SummaryOfSignificantAccountingPoliciesAndActivitiesTextualAbstract
Namespace Prefix: | sfst_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of minimum lease payments to be received by the lessor for capital leases. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 30 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84165051&loc=d3e45377-112738 + Details
Name: | us-gaap_CapitalLeasesFutureMinimumPaymentsReceivable
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.1) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_CashEquivalentsAtCarryingValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant