Consolidated and Combined Statements of Financial Condition (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accounts receivable, allowance for doubtful accounts	$ 1,149	$ 1,552
Investments at fair value, cost basis	$ 38,628	$ 39,999
Treasury stock, shares	263,622	0
Class A common stock
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	20,536,740	19,770,893
Common stock, shares outstanding	20,273,118	19,770,893
Class B common stock
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	31,229,236	31,621,542
Common stock, shares outstanding	31,229,236	31,621,542