8. Investment In and Advances to Affiliates (Details) (Siebert Brandford Shank Co LLC [Member], USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Siebert Brandford Shank Co LLC [Member]
Total assets, including secured demand note of $1,200,000 due from Siebert	$ 22,413,000		$ 22,413,000
Total liabilities, including subordinated liabilities of $1,200,000 due to Siebert	5,705,000		5,705,000
Total members' capital	16,708,000		16,708,000
Regulatory minimum net capital requirement	250,000		250,000
Total revenues	4,649,000	5,034,000	12,384,000	9,028,000
Net income (loss)	$ (671,000)	$ (713,000)	$ 810,000	$ (1,941,000)