Regulatory Requirements	9 Months Ended
Regulatory Requirements	Sep. 30, 2020
Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract]
Regulatory Requirements	Regulatory Requirements Certain subsidiaries of the Company are subject to various regulatory requirements in the United States, United Kingdom, Germany, Australia and certain other jurisdictions, which specify, among other requirements, minimum net capital requirements for registered broker-dealers. G&Co is subject to the SEC’s Uniform Net Capital requirements under Rule 15c3-1 (the “Rule”), which specifies, among other requirements, minimum net capital requirements for registered broker-dealers. The Rule requires G&Co to maintain a minimum net capital of the greater of $5,000 or 1/15 of aggregate indebtedness, as defined in the Rule. As of September 30, 2020, G&Co’s net capital was $31.0 million, which exceeded its requirement by $30.5 million. G&Co’s aggregate indebtedness to net capital ratio was 0.2 to 1 at September 30, 2020. Certain distributions and other capital withdrawals of G&Co are subject to certain notifications and restrictive provisions of the Rule. At September 30, 2020 GCI and GCE are subject to capital requirements of the FCA. Greenhill Australia is subject to capital requirements of the ASIC. We are also subject to certain capital regulatory requirements in other jurisdictions. As of September 30, 2020, GCI, GCE, Greenhill Europe, Greenhill Australia, and our other regulated operations were in compliance with local capital adequacy requirements.

The entire disclosure for regulatory capital requirement for depository and lending institutions. Institutions include, but not are not limited to, finance company, insured depository institution, bank holding company, savings and loan association holding company, bank and savings institution not federally insured, mortgage company, foreign financial institution and credit union.