Principles of Consolidation	3 Months Ended
Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Principles of Consolidation	Principles of Consolidation

Principles of Consolidation Disclosure [Text Block]

No definition available.

Name:	sfdl_PrinciplesOfConsolidationDisclosureTextBlock
Namespace Prefix:	sfdl_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration