8. Investment In and Advances to Affiliates (Details) (Siebert Brandford Shank Co LLC [Member], USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Siebert Brandford Shank Co LLC [Member]
Total assets, including secured demand note of $1,200,000 due from Siebert	$ 25,802,000		$ 25,802,000
Total liabilities, including subordinated liabilities of $1,200,000 due to Siebert	9,905,000		9,905,000
Total members' capital	15,897,000		15,897,000
Regulatory minimum net capital requirement	250,000		250,000
Total revenues	4,277,000	7,962,000	16,661,000	16,991,000
Net income (loss)	$ (802,000)	$ 1,562,000	$ 8,000	$ (380,000)