Fair Value Measurements (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Assets
Securities owned, at fair value:	$ 6,157	$ 5,598
Liabilities
Securities sold, not yet purchased, at fair value:	4,019	2,637
Recurring basis | Level 1
Assets
Total Assets	6,158	5,631
Liabilities
Total Liabilities	4,019	2,637
Recurring basis | Level 1 | Tax free money market mutual funds
Assets
Cash and cash equivalents:		33
Recurring basis | Level 1 | Money market mutual funds
Assets
Cash and cash equivalents:	1
Recurring basis | Level 1 | Corporate stocks-trading securities
Assets
Securities owned, at fair value:	3,330	2,571
Liabilities
Securities sold, not yet purchased, at fair value:	4,019	2,637
Recurring basis | Level 1 | Mutual funds
Assets
Securities owned, at fair value:	2,827	3,027
Total | Recurring basis
Assets
Total Assets	6,158	5,631
Liabilities
Total Liabilities	4,019	2,637
Total | Recurring basis | Tax free money market mutual funds
Assets
Cash and cash equivalents:		33
Total | Recurring basis | Money market mutual funds
Assets
Cash and cash equivalents:	1
Total | Recurring basis | Corporate stocks-trading securities
Assets
Securities owned, at fair value:	3,330	2,571
Liabilities
Securities sold, not yet purchased, at fair value:	4,019	2,637
Total | Recurring basis | Mutual funds
Assets
Securities owned, at fair value:	$ 2,827	$ 3,027