Condensed Consolidated Statements of Financial Condition (Parenthetical) (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accounts Receivable, allowance for doubtful accounts	$ 279	$ 726
Treasury Stock, Shares	1,353,398	1,353,398
Class A Common Stock
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	3,000,000,000	3,000,000,000
Common Stock, Shares Issued	25,078,345	23,940,185
Common Stock, Shares Outstanding	23,724,947	22,586,787
Class B Common Stock
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	1,000,000	1,000,000
Common Stock, Shares Issued	200	199
Common Stock, Shares Outstanding	200	199