Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Accounts receivable, allowance for doubtful accounts | $ 475 | $ 1,149 |
| Investments at fair value, cost basis | $ 33,593 | $ 38,628 |
| Treasury stock, shares | 387,890 | 263,622 |
| 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 | 20,948,998 | 20,536,740 |
| Common stock, shares outstanding | 20,561,108 | 20,273,118 |
| 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 | 31,138,193 | 31,229,236 |
| Common stock, shares outstanding | 31,138,193 | 31,229,236 |