Condensed Consolidated Statements of Financial Condition (Parenthetical) (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Accounts Receivable, allowance for doubtful accounts	$ 350	$ 726
Treasury Stock, Shares	1,992,602	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	25,101,023	23,940,185
Common Stock, Shares Outstanding	23,108,421	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	203	199
Common Stock, Shares Outstanding	203	199