Equity	3 Months Ended
Mar. 31, 2014
Stockholders' Equity Note [Abstract]
Equity	Equity On March 19, 2014, a dividend of $0.45 per share was paid to stockholders of record on March 5, 2014. Dividends include dividend equivalents of $1.6 million, which were paid on outstanding restricted stock units during each of the three months ended March 31, 2014 and March 31, 2013. During the three months ended March 31, 2014, 822,312 restricted stock units vested and were issued as common stock of which the Company is deemed to have repurchased 323,190 shares at an average price of $52.06 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 three months ended March 31, 2013, 482,711 restricted stock units vested and were issued as common stock of which the Company is deemed to have repurchased 177,969 shares at an average price of $58.88 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 three months ended March 31, 2013, the Company repurchased in open market transactions 169,809 shares of its common stock at an average price of $58.93 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 converts 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

3 Months Ended

Mar. 31, 2014

Stockholders' Equity Note [Abstract]

On March 19, 2014, a dividend of $0.45 per share was paid to stockholders of record on March 5, 2014. Dividends include dividend equivalents of $1.6 million, which were paid on outstanding restricted stock units during each of the three months ended March 31, 2014 and March 31, 2013.

During the three months ended March 31, 2014, 822,312 restricted stock units vested and were issued as common stock of which the Company is deemed to have repurchased 323,190 shares at an average price of $52.06 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 three months ended March 31, 2013, 482,711 restricted stock units vested and were issued as common stock of which the Company is deemed to have repurchased 177,969 shares at an average price of $58.88 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 three months ended March 31, 2013, the Company repurchased in open market transactions 169,809 shares of its common stock at an average price of $58.93 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 converts 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.