Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accounts Receivable, allowances	$ 1,313	$ 1,362
Furniture, Equipment and Leasehold Improvements, accumulated depreciation and amortization	42,656	33,980
Intangible Assets, accumulated amortization	$ 21,754	$ 33,735
Treasury Stock, Shares	15,626,288	10,159,116
Class A [Member]
Common Stock, par value	$ 0.01	$ 0.01
Common Stock, shares authorized	1,000,000,000	1,000,000,000
Common Stock, shares issued	55,249,559	46,414,240
Common Stock, shares outstanding	39,623,271	36,255,124
Class B [Member]
Common Stock, par value	$ 0.01	$ 0.01
Common Stock, shares authorized	1,000,000	1,000,000
Common Stock, shares issued	25	27
Common Stock, shares outstanding	25	27