Equity	9 Months Ended
Sep. 30, 2014
Stockholders' Equity Note [Abstract]
Equity	Equity On September 17, 2014, a dividend of $0.45 per share was paid to stockholders of record on September 3, 2014. Dividends include dividend equivalents of $4.0 million and $4.7 million, which were paid on outstanding restricted stock units for each of the nine months ended September 30, 2014 and 2013, respectively. During the nine months ended September 30, 2014, 958,178 restricted stock units vested and were issued as common stock of which the Company is deemed to have repurchased 380,130 shares at an average price of $51.51 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, 2014, the Company repurchased in open market transactions 212,200 shares of its common stock at an average price of $47.15 per share. During the nine months ended September 30, 2013, 662,569 restricted stock units vested and were issued as common stock of which the Company is deemed to have repurchased 214,303 shares at an average price of $57.22 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, 2013, the Company repurchased in open market transactions 853,870 shares of its common stock at an average price of $49.81 per share. In connection with the acquisition of Greenhill Australia in April 2010, the Company issued 1,099,877 shares of contingent convertible preferred stock ("Performance Stock"). The Performance Stock does not pay dividends, was issued in tranches of 659,926 shares and 439,951 shares, and will convert to shares of the Company's common stock on a one for one basis promptly after the third and fifth anniversary of the closing of the acquisition, respectively, if certain separate revenue targets are achieved. The revenue target for the first tranche was achieved on April 1, 2013, the third anniversary of the closing, and 659,926 shares of Performance Stock, which had a fair value of $32.5 million at the acquisition date, were converted to common stock. If the revenue target for the second tranche is achieved, the Performance Stock in that tranche will be converted to common stock on April 1, 2015. If the revenue target for the second tranche is not achieved, the Performance Stock in that tranche will be canceled.

Equity

9 Months Ended

Sep. 30, 2014

Stockholders' Equity Note [Abstract]

On September 17, 2014, a dividend of $0.45 per share was paid to stockholders of record on September 3, 2014. Dividends include dividend equivalents of $4.0 million and $4.7 million, which were paid on outstanding restricted stock units for each of the nine months ended September 30, 2014 and 2013, respectively.

During the nine months ended September 30, 2014, 958,178 restricted stock units vested and were issued as common stock of which the Company is deemed to have repurchased 380,130 shares at an average price of $51.51 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, 2014, the Company repurchased in open market transactions 212,200 shares of its common stock at an average price of $47.15 per share.

During the nine months ended September 30, 2013, 662,569 restricted stock units vested and were issued as common stock of which the Company is deemed to have repurchased 214,303 shares at an average price of $57.22 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, 2013, the Company repurchased in open market transactions 853,870 shares of its common stock at an average price of $49.81 per share.

In connection with the acquisition of Greenhill Australia in April 2010, the Company issued 1,099,877 shares of contingent convertible preferred stock ("Performance Stock"). The Performance Stock does not pay dividends, was issued in tranches of 659,926 shares and 439,951 shares, and will convert to shares of the Company's common stock on a one for one basis promptly after the third and fifth anniversary of the closing of the acquisition, respectively, if certain separate revenue targets are achieved. The revenue target for the first tranche was achieved on April 1, 2013, the third anniversary of the closing, and 659,926 shares of Performance Stock, which had a fair value of $32.5 million at the acquisition date, were converted to common stock. If the revenue target for the second tranche is achieved, the Performance Stock in that tranche will be converted to common stock on April 1, 2015. If the revenue target for the second tranche is not achieved, the Performance Stock in that tranche will be canceled.