Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 14, 2018
Document And Entity Information
Entity Registrant Name	Siebert Financial Corp
Entity Central Index Key	0000065596
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Is Entity a Well-known Seasoned Issuer?	No
Is Entity a Voluntary Filer?	No
Is Entity's Reporting Status Current?	Yes
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		27,157,188
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2018