Regulatory Authorities - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
EGL [Member]
Regulatory Authorities [Line Items]
Alternative Net Capital Requirement		$ 250,000
Net Capital		82,700,000	$ 74,080,000
Alternative excess net capital		82,450,000	73,830,000
International Strategy & Investment Group LLC [Member]
Regulatory Authorities [Line Items]
Alternative Net Capital Requirement		250,000
Net Capital		12,565,000	7,548,000
Alternative excess net capital		12,315,000	$ 7,298,000
Evercore Trust Company [Member]
Regulatory Authorities [Line Items]
Tier One Capital		5,000,000
Minimum liquid assets, amount		3,500,000
Coverage of operating expenses (in days)	90 days
Collateral held in a segregated account at a third-party depository institution		$ 10,000,000