Share-Based and Other Deferred Compensation - Additional information (Detail) In Thousands, except Share data, unless otherwise specified	3 Months Ended		12 Months Ended			3 Months Ended	12 Months Ended						12 Months Ended												12 Months Ended		3 Months Ended		12 Months Ended								12 Months Ended							2 Months Ended		1 Months Ended		12 Months Ended		12 Months Ended	0 Months Ended	12 Months Ended			0 Months Ended	12 Months Ended				0 Months Ended	12 Months Ended
	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Sep. 30, 2013 Long Term Incentive Plan [Member]	Dec. 31, 2014 Long Term Incentive Plan [Member] USD ($)	Dec. 31, 2013 Long Term Incentive Plan [Member] USD ($)	Dec. 31, 2014 Employee Loans [Member] USD ($)	Dec. 31, 2013 Employee Loans [Member] USD ($)	Dec. 31, 2014 Equity Grants [Member]	Dec. 31, 2013 Equity Grants [Member]	Dec. 31, 2014 Equity Grants [Member] Minimum [Member] USD ($)	Dec. 31, 2013 Equity Grants [Member] Minimum [Member] USD ($)	Dec. 31, 2012 Equity Grants [Member] Minimum [Member] USD ($)	Dec. 31, 2014 Equity Grants [Member] Maximum [Member] USD ($)	Dec. 31, 2013 Equity Grants [Member] Maximum [Member] USD ($)	Dec. 31, 2012 Equity Grants [Member] Maximum [Member] USD ($)	Dec. 31, 2013 Equity Grants [Member] Restricted Stock Units (RSUs) [Member] USD ($)	Dec. 31, 2012 Equity Grants [Member] Restricted Stock Units (RSUs) [Member] USD ($)	Dec. 31, 2014 Service Based Awards [Member] USD ($)	Dec. 31, 2014 Two Thousand Six Stock Incentive Plan [Member]	Dec. 31, 2013 Two Thousand Six Stock Incentive Plan [Member]	Dec. 31, 2014 Class A [Member] Restricted Stock Units (RSUs) [Member]	Dec. 31, 2014 Class A [Member] Two Thousand Six Stock Incentive Plan [Member]	Dec. 31, 2014 Restricted Stock Units (RSUs) [Member] Equity Grants [Member] USD ($)	Mar. 31, 2012 Deferred Cash Program [Member] USD ($)	Mar. 31, 2011 Deferred Cash Program [Member] USD ($)	Dec. 31, 2014 Deferred Cash Program [Member] USD ($)	Dec. 31, 2013 Deferred Cash Program [Member] USD ($)	Dec. 31, 2012 Deferred Cash Program [Member] USD ($)	Dec. 31, 2014 LP Units [Member]	Dec. 31, 2013 LP Units [Member] USD ($)	Dec. 31, 2012 LP Units [Member] USD ($)	Dec. 31, 2014 Lexicon [Member] Acquisition Related [Member]	Dec. 31, 2013 Lexicon [Member] Acquisition Related [Member]	Dec. 31, 2014 Lexicon [Member] Acquisition Related [Member] USD ($)	Dec. 31, 2013 Lexicon [Member] Acquisition Related [Member] USD ($)	Dec. 31, 2012 Lexicon [Member] Acquisition Related [Member] USD ($)	Dec. 31, 2014 Lexicon [Member] Acquisition Related [Member] Unvested Acquisition Related Equity Awards [Member] USD ($)	Dec. 31, 2011 Lexicon [Member] Acquisition Related [Member] Class A [Member]	Dec. 31, 2014 Evercore ISI [Member] Acquisition Related [Member] USD ($)	Dec. 31, 2014 Evercore ISI [Member] Acquisition Related [Member] Unvested Acquisition Related Equity Awards [Member] USD ($)	Feb. 25, 2015 Subsequent Event [Member] Other Deferred Cash [Member] USD ($)	Feb. 25, 2015 Subsequent Event [Member] Other Share Based Awards [Member]	Feb. 28, 2015 Subsequent Event [Member] Lexicon [Member] Acquisition Related [Member] GBP (£)	Feb. 28, 2015 Subsequent Event [Member] Lexicon [Member] Acquisition Related [Member] Class A [Member]	Dec. 31, 2014 Class E LP Units [Member] Evercore ISI [Member] Acquisition Related [Member]	Dec. 31, 2013 Class E LP Units [Member] Evercore ISI [Member] Acquisition Related [Member]	Dec. 31, 2014 Class E LP Units [Member] Evercore ISI [Member] Vested LP Units [Member]	Oct. 31, 2014 Class E LP Units [Member] Evercore ISI [Member] Unvested LP Units [Member]	Dec. 31, 2014 Class E LP Units [Member] Evercore ISI [Member] Unvested LP Units [Member]	Dec. 31, 2014 Class G Interests [Member] Evercore ISI [Member] Acquisition Related [Member]	Dec. 31, 2013 Class G Interests [Member] Evercore ISI [Member] Acquisition Related [Member]	Oct. 31, 2014 Class G Interests [Member] Evercore ISI [Member]	Dec. 31, 2014 Class G Interests [Member] Evercore ISI [Member] Vested LP Units [Member]	Dec. 31, 2014 Class G Interests [Member] Evercore ISI [Member] Unvested LP Units [Member]	Dec. 31, 2014 Class H Interests [Member] Evercore ISI [Member] Acquisition Related [Member]	Dec. 31, 2013 Class H Interests [Member] Evercore ISI [Member] Acquisition Related [Member]	Oct. 31, 2014 Class H Interests [Member] Evercore ISI [Member]	Dec. 31, 2014 Class H Interests [Member] Evercore ISI [Member] Vested LP Units [Member]	Dec. 31, 2014 Class H Interests [Member] Evercore ISI [Member] Unvested LP Units [Member]	Dec. 31, 2014 Special Charges [Member] USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Original Grant Of Vested Lp Units																																13,548,000
Original Grant Of Unvested Lp Units																																9,589,000
Limited Partnership Units Convertible Conversion Ratio																																1
Amortization of LP Units																																	$ 20,063	$ 20,971
Grant Of LP Units (in units)																																																		710,000	710,000	710,000			1,078,000	538,000	540,000			4,095,000	2,044,000	2,051,000
Class H Interests Performance Period			3 years
Compensation expense related to acquisition related awards																																					5,255	10,960	18,749			3,399
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized																					121,771								949											1,572			316,456
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition																					13 months								3 months											6 months			49 months
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares																																									1,883,000
Compensation expense related to deferred cash consideration																																					1,626	3,937	7,216
Grant Of Acquisition Related Deferred Compensation																																					1,892
Deferred Compensation Vesting Period																																					2 years
Expense Related To Acquisition Related Deferred Compensation																																						211	875
Deferred Cash Consideration Transfer Restrictions Released																																														3,190
Stock Authorized Under Plan																									20,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized		5,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant																						5,392,000	7,323,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number																								224,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number											5,348,000	6,680,000																							460,000	1,127,000												1,173,000	0				1,077,000	0				4,091,000	0
Grant Of Deferred Cash Compensation																											3,926	9,153																7,400
Deferred compensation, vesting period (in years)																													4 years
Compensation expense related to deferred compensation programs																													3,683	3,804	4,210
Long Term Incentive Plan Performance period (in years)						4 years
Long Term Incentive Plan Payment period (in years)						2 years
Deferred compensation arrangement compensation expense							5,700	1,584	13,851	7,433
Shares issued during period (in shares)											2,071,000								2,398,000	3,163,000						2,071,000									13,000										2,200,000			1,174,000					1,078,000					4,095,000
Weighted average grant date fair value (in dollars per share)													$ 46.59	$ 26.60	$ 22.62	$ 58.67	$ 55.24	$ 29.19
Vested											(3,245,000)								(2,188,000)	(1,760,000)						(3,245,000)									(680,000)													0					0					0
Forfeited											(158,000)								(60,000)	(256,000)						(158,000)									0													0					0					0
Compensation expense related to Service-based Award																			79,678	62,840						90,597
Requisite service period (in years)									one
Maximum contractual term (in years)									five
Unamortized deferred compensation									23,869
LP Units, Transfer Restrictions Released (in LP units)	1,267,000
Restricted Class A Shares, Transfer Restrictions Released (in shares)	610,000																																														531,000
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense			34,375	29,497	26,773
Awards Vesting Period																																													4 years
Expense Related To Separation Benefits			5,671	4,834	7,273																																																										3,372
Cash Payments Related To Separation Benefits			$ 3,415	$ 3,314	$ 5,135																																																										$ 238