Fair Value Accounting (Details Textual)	3 Months Ended
Mar. 31, 2015
Fair Value Accounting (Textual)
Percentage of loans collateralize by real estate	More than 80

Percentage of company's loans collateral by real estate.

No definition available.

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