2.4.0.82415401 - Disclosure - Regulatory Requirements - Additional Information (Detail)truefalsefalse1false USDfalsefalseD2013Q2YTDhttp://www.sec.gov/CIK0001282977duration2013-01-01T00:00:002013-06-30T00:00:00numberStandardhttp://www.xbrl.org/2003/instancepurexbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170$1true 1us-gaap_RegulatoryCapitalRequirementsAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Regulatory Capital Requirements [Abstract]2false 2us-gaap_MinimumNetCapitalRequiredForBrokerDealerSubsidiary1us-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse50005000USD$falsetruefalsexbrli:monetaryItemTypemonetaryMinimum amount of net capital required to be maintained by entity's broker-dealer subsidiary to engage in securities transactions.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Rule 15c3 -Number 240 -Section 1 -Paragraph 1 -Subparagraph i -Article 15c3 -Subsection a false2Minimum net capital requirements3false 2us-gaap_DescriptionOfCapitalRequirementsOnTrustAssetsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00The greater of $5,000 or 1/15 of aggregate indebtednessfalsefalsefalsexbrli:stringItemTypestringDescribes the capital requirements for trusts assets under management.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=7881181&loc=d3e65217-112826 false0Description of minimum net capital requirements4false 2us-gaap_NetCapitalus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse57000005700000falsefalsefalsexbrli:monetaryItemTypemonetaryNet capital is equal to the net worth of the broker dealer, less certain items such as exchange memberships, carrying value of securities not readily marketable, haircuts on marketable securities in proprietary accounts, furniture and equipment and other illiquid assets as defined.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Rule 15c3 -Number 240 -Section 1 -Paragraph 1 -Subparagraph ii -Article 15c3 -Subsection a Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-BRD -Paragraph 80 -Subparagraph Exhibit 4-8 -IssueDate 2006-05-01 -Chapter 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-BRD -Paragraph 80 -Subparagraph Exhibit 4-8, 15 -IssueDate 2006-05-01 -Chapter 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Net capital5false 2us-gaap_ExcessNetCapitalAt1500Percentus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse52000005200000USD$falsetruefalsexbrli:monetaryItemTypemonetaryThe amount of net capital in excess of the minimum required net capital.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Rule 15c3 -Number 240 -Section 1 -Paragraph 1 -Subparagraph i -Article 15c3 -Subsection a false2Excess net capital6false 2us-gaap_RatioOfIndebtednessToNetCapital1us-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse148.98148.98falsefalsefalsexbrli:pureItemTypepureIndebtedness divided by net capital.No definition available.false0Aggregate indebtedness to net capital ratiofalseRegulatory Requirements - Additional Information (Detail) (USD $)NoRoundingUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.greenhill.com/role/RegulatoryRequirementsAdditionalInformationDetail16