SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 2) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Securities and other investments owned
Securities owned	$ 95,965	$ 16,579
Securities sold not yet purchased:
Securities sold not yet purchased	25,046	846
Common Stocks and Warrants [Member]
Securities and other investments owned
Securities owned	41,412	2,084
Corporate Bonds [Member]
Securities and other investments owned
Securities owned	6,328	1,025
Securities sold not yet purchased:
Securities sold not yet purchased	982	846
Partnership Interests and Other [Member]
Securities and other investments owned
Securities owned	21,357	$ 13,470
Securities sold not yet purchased:
Securities sold not yet purchased	494
Common Stock [Member]
Securities sold not yet purchased:
Securities sold not yet purchased	23,570
Loans Receivable [Member]
Securities and other investments owned
Securities owned	$ 26,868