Equity	12 Months Ended
Dec. 31, 2015
Stockholders' Equity Note [Abstract]
Equity	Note 11 — Equity Dividends declared per common share were $1.80 for each of the years ended December 31, 2015, 2014 and 2013 and are paid on outstanding common shares. In addition, dividend equivalent amounts are paid on outstanding restricted stock units and amounted to $6.5 million, $5.5 million and $6.2 million for the years ended December 31, 2015, 2014 and 2013, respectively, and are included in dividends paid on the consolidated statements of cash flows. In the event a restricted stock unit holder’s employment is terminated, a portion of the dividend equivalent may be required to be paid back (a "clawback") to the Company and is netted against the dividend equivalent amounts. See “Note 14 — Restricted Stock Units”. In connection with the acquisition of Cogent, the Company issued 779,454 shares of common stock on the acquisition date, April 1, 2105. In addition, the Company will issue 334,048 shares of common stock on the second or fourth anniversary of the Acquisition, as the case may be, if the revenue target related to the Earnout is achieved. If the revenue target related to the Earnout is not achieved the common shares will not be issued. The fair value of the contingent issuance of common shares was valued on the date of the acquisition at $11.9 million and has been recorded as additional paid in capital in the consolidated statements of financial condition. A portion of the value will be transferred to common stock if the Earnout is achieved. See "Note 3 — Acquisition" and "Note 12 — Earnings per Share". During 2015, 826,673 restricted stock units vested and were issued as common stock of which the Company is deemed to have repurchased 341,235 shares at an average price of $34.88 per share in conjunction with the payment of tax liabilities in respect of stock delivered to its employees in settlement of restricted stock units. During 2014, 1,019,989 restricted stock units vested and were issued as common stock of which the Company is deemed to have repurchased 404,611 shares at an average price of $51.26 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 2014 the Company repurchased in open market transactions 334,935 shares of its common stock at an average price of $46.09. 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 did not pay dividends, was issued in tranches of 659,926 shares and 439,951 shares, and was convertible to shares of the Company’s common stock promptly after the third and fifth anniversaries of the closing of the acquisition, respectively, if certain separate revenue targets were achieved. The revenue target for the first tranche was achieved and on April 1, 2013, the third anniversary of the closing, 659,926 shares of Performance Stock, which had a fair value of $32.5 million at the acquisition date, were converted to common stock. The revenue target for the second tranche was not achieved and, effective April 1, 2015, the fifth anniversary of the closing, 439,951 shares of Performance Stock, which had a fair value of $14.4 million at the acquisition date, were canceled and the value was transferred to additional paid in capital.

Equity

12 Months Ended

Dec. 31, 2015

Stockholders' Equity Note [Abstract]

Note 11 — Equity

Dividends declared per common share were $1.80 for each of the years ended December 31, 2015, 2014 and 2013 and are paid on outstanding common shares. In addition, dividend equivalent amounts are paid on outstanding restricted stock units and amounted to $6.5 million, $5.5 million and $6.2 million for the years ended December 31, 2015, 2014 and 2013, respectively, and are included in dividends paid on the consolidated statements of cash flows. In the event a restricted stock unit holder’s employment is terminated, a portion of the dividend equivalent may be required to be paid back (a "clawback") to the Company and is netted against the dividend equivalent amounts. See “Note 14 — Restricted Stock Units”.

In connection with the acquisition of Cogent, the Company issued 779,454 shares of common stock on the acquisition date, April 1, 2105. In addition, the Company will issue 334,048 shares of common stock on the second or fourth anniversary of the Acquisition, as the case may be, if the revenue target related to the Earnout is achieved. If the revenue target related to the Earnout is not achieved the common shares will not be issued. The fair value of the contingent issuance of common shares was valued on the date of the acquisition at $11.9 million and has been recorded as additional paid in capital in the consolidated statements of financial condition. A portion of the value will be transferred to common stock if the Earnout is achieved. See "Note 3 — Acquisition" and "Note 12 — Earnings per Share".

During 2015, 826,673 restricted stock units vested and were issued as common stock of which the Company is deemed to have repurchased 341,235 shares at an average price of $34.88 per share in conjunction with the payment of tax liabilities in respect of stock delivered to its employees in settlement of restricted stock units.

During 2014, 1,019,989 restricted stock units vested and were issued as common stock of which the Company is deemed to have repurchased 404,611 shares at an average price of $51.26 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 2014 the Company repurchased in open market transactions 334,935 shares of its common stock at an average price of $46.09.

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 did not pay dividends, was issued in tranches of 659,926 shares and 439,951 shares, and was convertible to shares of the Company’s common stock promptly after the third and fifth anniversaries of the closing of the acquisition, respectively, if certain separate revenue targets were achieved. The revenue target for the first tranche was achieved and on April 1, 2013, the third anniversary of the closing, 659,926 shares of Performance Stock, which had a fair value of $32.5 million at the acquisition date, were converted to common stock. The revenue target for the second tranche was not achieved and, effective April 1, 2015, the fifth anniversary of the closing, 439,951 shares of Performance Stock, which had a fair value of $14.4 million at the acquisition date, were canceled and the value was transferred to additional paid in capital.