Share-Based and Other Deferred Compensation (Details) $ / shares in Units, $ in Thousands		1 Months Ended				3 Months Ended				9 Months Ended		12 Months Ended
	Feb. 15, 2020 shares	Jun. 30, 2019 USD ($) shares	Nov. 30, 2017 USD ($) shares	Jul. 31, 2017 vote shares	Nov. 30, 2016 USD ($) tranche Number_Of_Anniversaries shares	Sep. 30, 2020 USD ($) shares	Jun. 30, 2020 shares	Mar. 31, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) payment_installment Installments $ / shares shares	Sep. 30, 2019 USD ($)	Dec. 31, 2020 USD ($) shares	Dec. 31, 2019 USD ($)	Dec. 31, 2017 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Cost Not Yet Recognized						$ 197,164				$ 197,164
Deferred Compensation Arrangement With Individual, Total Compensation Cost Not Yet Recognized Period For Recognition										31 months
Deferred Compensation Arrangement Compensation Expense						$ 30,164			$ 20,688	$ 95,178	$ 73,456
Headcount Reductions (as a percent)						8.00%				8.00%
Severance Costs									2,762	$ 26,967	7,575
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Severance Costs									691		1,911
Restricted Stock Units (RSUs) [Member] | Forecast [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock Units Related to Restructuring | shares												172,000
Cash and Deferred Cash Compensation [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Severance Costs									2,071		5,664
Special Charges [Member] | Separation Benefits and Stay Arrangements [Member] | Forecast [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Severance Costs												$ 27,877
Special Charges [Member] | Deferred Compensation [Member] | Forecast [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Severance Costs												15,123
Special Charges [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Severance Costs						$ 3,102				10,437			$ 1,272
Special Charges [Member] | Restricted Stock Units (RSUs) [Member] | Forecast [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Severance Costs												$ 11,911
Special Charges [Member] | Cash and Deferred Cash Compensation [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Severance Costs						$ 4,151				$ 26,967			$ 1,578
LP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Limited Partnership Units Convertible Conversion Ratio					1	1				1
Amended Two Thousand Sixteen Stock Incentive Plan [Member] | Class A [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Additional Shares Authorized (in shares) | shares							6,000,000
Number of Shares Available for Grant (in shares) | shares						7,030,000				7,030,000
Long Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement Compensation Expense						$ 9,160		$ (6,810)	8,302	$ 5,339	24,928
Long Term Incentive Plan Performance Period (in years)										4 years
Number of Payment Installments | payment_installment										3
Deferred Compensation Arrangement with Individual, Distribution Paid											19,516
Long Term Incentive Plan [Member] | Current Liabilities [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Recorded Liability						34,215				$ 34,215
Long Term Incentive Plan [Member] | Noncurrent Liabilities [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Recorded Liability						$ 68,431				$ 68,431
Class J LP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Limited Partners' Capital Account, Units Outstanding | shares						0				0
Issued LP Units (in shares) | shares						0				0
Class J LP Units [Member] | Acquisition Related [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Vested During Period (in shares) | shares	223,000
Limited Partners' Capital Account, Units Outstanding | shares						0				0
Issued LP Units (in shares) | shares						0				0
Class I-P Units [Member] | Board of Directors Chairman [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Expense						$ 1,164			1,164	$ 3,468	3,455
Grant of I-P Units (in units) | shares					400,000
Retirement Notice Requirement					1 year
Number of Tranches of Class I-P Units | tranche					2
Number of Class I-P Units in Each Tranche (in units) | shares					200,000
Number of Consecutive Trading Days Required for Class I-P Units to Exceed Thresholds					20 days
Grant of I-P Units, Fair Value of Award					$ 24,412
Class K-P Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Expense						3,066			1,277	$ 5,392	1,911
Grant of K-P Units (in units) | shares		220,000	64,000
K-P Units to be Granted Upon Achievement of Benchmarks (in units) | shares			16,000
Grant of K-P Units, Fair Value of Award		$ 21,692	$ 6,250
Class K-P Units [Member] | Share-based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant of K-P Units (in units) | shares		120,000
Class K-P Units [Member] | Share-based Payment Arrangement, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant of K-P Units (in units) | shares		100,000
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation, Vesting Period (in years)										4 years
Restricted Stock Units (RSUs) [Member] | 2016 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Issued During Period (in shares) | shares										1,946,000
Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares										$ 80.94
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grant Date Weighted Average Fair Value, Granted										$ 157,467
Restricted Stock Units (RSUs) [Member] | 2016 Stock Incentive Plan [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares										$ 44.21
Restricted Stock Units (RSUs) [Member] | 2016 Stock Incentive Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares										$ 81.53
Restricted Stock Units (RSUs) [Member] | 2006 and 2016 Stock Incentive Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Expense						46,880			50,152	$ 147,352	162,296
Shares Vested During Period (in shares) | shares										2,529,000
Shares Forfeited During Period (in shares) | shares										103,000
Deferred Cash Compensation Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation, Vesting Period (in years)										4 years
Deferred Compensation Arrangement with Individual, Cash Award Granted, Amount						1,460		$ 179,705		$ 1,460
Restricted Cash Award [Member] | Board of Directors Chairman [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Retirement Notice Requirement					6 months
Deferred Compensation Arrangement with Individual, Cash Award Granted, Amount					$ 35,000
Deferred Compensation Arrangement With Individual Cash Award Tranche One Vesting Amount					11,000
Deferred Compensation Arrangement With Individual Cash Award Tranche Two Vesting Amount					6,000
Deferred Compensation Arrangement With Individual Cash Award Tranche Three Vesting Amount					$ 6,000
Awards Vesting Period | Number_Of_Anniversaries					3
Restricted Cash Award [Member] | Board of Directors Chairman [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Cash Award Granted, Amount					$ 8,750
Restricted Cash Award [Member] | Board of Directors Chairman [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Cash Award Granted, Amount					$ 35,000
Other Deferred Cash [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Cash Award Granted, Amount														$ 29,500
Awards Vesting Period | Installments										5
Long Term Incentive Plan [Member] | 2017 Long-term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Cost Not Yet Recognized						30,627				$ 30,627
Employee Loans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement Compensation Expense						8,101			6,631	16,516	15,976
Deferred Compensation Arrangement with Individual, Recorded Liability						$ 34,852				$ 34,852
Requisite Service Period (in years)										1 year
Maximum Contractual Term (in years)										5 years
Evercore ISI [Member] | Class H LP Interests [Member] | Acquisition Related [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Units Outstanding (in units) | shares				4,148,000
Evercore ISI [Member] | Class J LP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Number of Votes | vote				1
Evercore ISI [Member] | Class J LP Units [Member] | Class B [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Issued During Period, Shares, New Issues | shares				1
Evercore ISI [Member] | Class J LP Units [Member] | Acquisition Related [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Expense									$ 4,527	$ 1,067	$ 12,276
Evercore ISI [Member] | Vested LP Units [Member] | Class J LP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant of LP Units (in units) | shares				1,012,000
Evercore ISI [Member] | Vested LP Units [Member] | Class J LP Units [Member] | Subject to Continued Employment [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant of LP Units (in units) | shares				963,000
Evercore ISI [Member] | Unvested LP Units [Member] | Class J LP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant of LP Units (in units) | shares				938,000