Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclsoure [Line Items]
Foreign loss carryforwards	$ 7,800,000
Deferred tax assets, compensation deductible	800,000
Valuation Allowance, Amount	4,938,000	7,611,000
Foreign tax credit carryforwards	4,252,000	6,206,000
Income Taxes Receivable, Current	1,500,000	0
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount	2,200,000
Current income taxes payable	15,345,000	15,797,000
U.S. statutory tax rate (percent)	35.00%	35.00%	35.00%
Greenhill & Co., Europe Holdings, Limited [Member]
Income Tax Disclsoure [Line Items]
Valuation Allowance, Amount	2,800,000	1,900,000
US Foreign Tax Credit Carryforwards [Member]
Income Tax Disclsoure [Line Items]
Valuation Allowance, Amount	2,100,000	5,700,000
Foreign loss carryforward, 7-8 years [Member]
Income Tax Disclsoure [Line Items]
Foreign loss carryforwards	1,800,000
Foreign loss carryforward, 17 years or longer [Member]
Income Tax Disclsoure [Line Items]
Foreign loss carryforwards	$ 6,000,000
Minimum period carried forward	17 years