8. Investment In and Advances to Affiliates (Details) (SbsFinancialProductsCompanyLlcMember, USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
SbsFinancialProductsCompanyLlcMember
Total assets, including secured demand note of $1,200,000 due from Siebert	$ 23,931,000
Total liabilities, including subordinated liabilities of $1,200,000 due to Siebert	7,111,000
Total members capital	16,820,000
Regulatory minimum net capital requirement	250,000
Total revenues	3,995,000	5,626,000
Net income (loss)	$ (1,229,000)	$ (299,000)