Retirement Plan	12 Months Ended
Dec. 31, 2012
Compensation and Retirement Disclosure [Abstract]
Retirement Plan	Retirement Plan In the U.S., the Company sponsors a qualified defined contribution plan (the “Retirement Plan”) covering all eligible employees of G&Co. The Retirement Plan provides for both employee contributions in accordance with Section 401(k) of the Internal Revenue Code, and employer discretionary profit sharing contributions, subject to statutory limits. Participants may contribute up to 50% of eligible compensation, as defined. The Company provides matching contributions of up to $1,000 per employee. The Company incurred costs of $0.3 million, $0.3 million and $0.2 million for contributions to the Retirement Plan for the years ended December 31, 2012, 2011 and 2010, respectively. There was $0.1 million and $0.2 million related to contributions due to the Retirement Plan included in compensation payable at December 31, 2012 and 2011, respectively. GCI also operates a defined contribution pension fund for its employees. The assets of the pension fund are held separately in an independently administered fund. For the years ended December 31, 2012, 2011 and 2010, GCI incurred costs of approximately $0.7 million, $0.6 million and $0.7 million, respectively. At December 31, 2012 and 2011, there were no amounts related to contributions due to the defined contribution pension fund included in compensation payable. Greenhill Australia is required by Australian law to contribute compulsory superannuation on employees' gross earnings, generally at a rate of 9%. Superannuation is a defined contribution plan in which retirement benefits are determined by the contribution accumulated over the working life plus investment earnings within the fund less expenses. Greenhill Australia incurred such costs of approximately $0.6 million, $0.6 million and $0.4 million for the years ended December 31, 2012, 2011 and 2010, respectively. At December 31, 2012 and 2011, there were no amounts related to superannuation contributions due to the defined contribution plan included in compensation payable.

Retirement Plan

12 Months Ended

Dec. 31, 2012

Compensation and Retirement Disclosure [Abstract]

In the U.S., the Company sponsors a qualified defined contribution plan (the “Retirement Plan”) covering all eligible employees of G&Co. The Retirement Plan provides for both employee contributions in accordance with Section 401(k) of the Internal Revenue Code, and employer discretionary profit sharing contributions, subject to statutory limits. Participants may contribute up to 50% of eligible compensation, as defined. The Company provides matching contributions of up to $1,000 per employee. The Company incurred costs of $0.3 million, $0.3 million and $0.2 million for contributions to the Retirement Plan for the years ended December 31, 2012, 2011 and 2010, respectively. There was $0.1 million and $0.2 million related to contributions due to the Retirement Plan included in compensation payable at December 31, 2012 and 2011, respectively.

GCI also operates a defined contribution pension fund for its employees. The assets of the pension fund are held separately in an independently administered fund. For the years ended December 31, 2012, 2011 and 2010, GCI incurred costs of approximately $0.7 million, $0.6 million and $0.7 million, respectively. At December 31, 2012 and 2011, there were no amounts related to contributions due to the defined contribution pension fund included in compensation payable.

Greenhill Australia is required by Australian law to contribute compulsory superannuation on employees' gross earnings, generally at a rate of 9%. Superannuation is a defined contribution plan in which retirement benefits are determined by the contribution accumulated over the working life plus investment earnings within the fund less expenses. Greenhill Australia incurred such costs of approximately $0.6 million, $0.6 million and $0.4 million for the years ended December 31, 2012, 2011 and 2010, respectively. At December 31, 2012 and 2011, there were no amounts related to superannuation contributions due to the defined contribution plan included in compensation payable.