Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Aug. 13, 2018
Entity [Abstract]
Entity Registrant Name	Security Federal Corporation
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Amendment Flag	false
Entity Central Index Key	0000818677
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		2,953,424
Entity Filer Category	Smaller Reporting Company
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q1