Equity	9 Months Ended
Sep. 30, 2017
Stockholders' Equity Note [Abstract]
Equity	Equity On September 27, 2017, a dividend of $0.45 per share was paid to stockholders of record on September 13, 2017. For the nine months ended September 30, 2017, dividend payments of $1.35 per share were paid to stockholders. Dividends include dividend equivalents of $6.2 million and $6.4 million, which were paid on outstanding restricted stock units for the nine months ended September 30, 2017 and 2016, respectively. During the nine months ended September 30, 2017, 1,095,224 restricted stock units vested and were settled in shares of common stock of which the Company is deemed to have repurchased 448,738 shares at an average price of $29.06 per share in conjunction with the payment of tax liabilities in respect of stock delivered to its employees in settlement of restricted stock units. During the nine months ended September 30, 2016, 850,387 restricted stock units vested and were settled in shares of common stock of which the Company is deemed to have repurchased 319,194 shares at an average price of $25.10 per share in conjunction with the payment of tax liabilities in respect of stock delivered to its employees in settlement of restricted stock units. In addition, during the nine months ended September 30, 2016, the Company repurchased in open market transactions 626,455 shares of its common stock at an average price of $20.22 per share. On September 25, 2017, the Company announced that its Board of Directors had authorized the repurchase of up to $285 million of the Company's common stock and approved a cash tender offer for up to 9,000,000 shares of the Company's common stock at a purchase price of $17.00 per share, which was subsequently increased to up to 12,000,000 shares of the Company's common stock at a purchase price of $17.25 per share. Prior to the public announcement of the tender offer, the Company's Chairman, through an entity controlled by him, and the Company's Chief Executive Officer, in his personal capacity and through an entity controlled by him, each entered into a Subscription Agreement for the purchase of $10.0 million, for an aggregate total of $20.0 million, of the Company's common stock at the final tender offer price per share. The funding of the purchases by the Chairman and Chief Executive Officer occurred on November 9, 2017, the 11th trading day following the expiration date of the tender offer, and a total of 1,159,420 common shares were issued. Under the requirements of ASC 505, these purchases were included in subscription receivable on the condensed consolidated statement of financial condition. See "Note 6 — Related Parties" and "Note 12 — Subsequent Events".

Equity

On September 27, 2017, a dividend of $0.45 per share was paid to stockholders of record on September 13, 2017. For the nine months ended September 30, 2017, dividend payments of $1.35 per share were paid to stockholders. Dividends include dividend equivalents of $6.2 million and $6.4 million, which were paid on outstanding restricted stock units for the nine months ended September 30, 2017 and 2016, respectively.

During the nine months ended September 30, 2017, 1,095,224 restricted stock units vested and were settled in shares of common stock of which the Company is deemed to have repurchased 448,738 shares at an average price of $29.06 per share in conjunction with the payment of tax liabilities in respect of stock delivered to its employees in settlement of restricted stock units.

During the nine months ended September 30, 2016, 850,387 restricted stock units vested and were settled in shares of common stock of which the Company is deemed to have repurchased 319,194 shares at an average price of $25.10 per share in conjunction with the payment of tax liabilities in respect of stock delivered to its employees in settlement of restricted stock units. In addition, during the nine months ended September 30, 2016, the Company repurchased in open market transactions 626,455 shares of its common stock at an average price of $20.22 per share.

On September 25, 2017, the Company announced that its Board of Directors had authorized the repurchase of up to $285 million of the Company's common stock and approved a cash tender offer for up to 9,000,000 shares of the Company's common stock at a purchase price of $17.00 per share, which was subsequently increased to up to 12,000,000 shares of the Company's common stock at a purchase price of $17.25 per share. Prior to the public announcement of the tender offer, the Company's Chairman, through an entity controlled by him, and the Company's Chief Executive Officer, in his personal capacity and through an entity controlled by him, each entered into a Subscription Agreement for the purchase of $10.0 million, for an aggregate total of $20.0 million, of the Company's common stock at the final tender offer price per share. The funding of the purchases by the Chairman and Chief Executive Officer occurred on November 9, 2017, the 11th trading day following the expiration date of the tender offer, and a total of 1,159,420 common shares were issued. Under the requirements of ASC 505, these purchases were included in subscription receivable on the condensed consolidated statement of financial condition. See "Note 6 — Related Parties" and "Note 12 — Subsequent Events".