CONSOLIDATED STATEMENTS OF CHANGES IN MEZZANINE EQUITY AND SHAREHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Performance-Based Restricted Stock Units (PSUs)	Leveraged Stock Units (LSUs)	Cumulative-effect adjustment from adoption of ASC 2020-06	Class A Common Stock	Class A Common Stock Performance-Based Restricted Stock Units (PSUs)	Class A Common Stock Leveraged Stock Units (LSUs)	Additional Paid-In Capital	Additional Paid-In Capital Performance-Based Restricted Stock Units (PSUs)	Additional Paid-In Capital Leveraged Stock Units (LSUs)	Additional Paid-In Capital Cumulative-effect adjustment from adoption of ASC 2020-06	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Accumulated Deficit)	Retained Earnings (Accumulated Deficit) Cumulative-effect adjustment from adoption of ASC 2020-06	Treasury Stock
Beginning balance (in shares) at Dec. 31, 2021					90,759,000
Beginning balance at Dec. 31, 2021	$ 693,633			$ (66,383)	$ 908			$ 1,340,989			$ (106,172)	$ (362)	$ (626,779)	$ 39,789	$ (21,123)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	19,350							19,350
Exercise of stock options (in shares)					354,000
Exercise of stock options	3,280				$ 3			3,277
Restricted stock units vested, net of shares withheld for taxes (in shares)					452,000
Restricted stock units vested, net of shares withheld for taxes	(6,187)				$ 5			(6,192)
Stock units vested, net of shares withheld for taxes (in shares)					459,000
Stock units vested, net of shares withheld for taxes	(11,232)				$ 5			(11,237)
Exchange and conversion of 2024 notes (in shares)					5,394,000
Exchange and conversion of 2024 notes	101,999				$ 54			101,945
Shares issued for acquisition (in shares)					3,742,000
Shares issued for acquisition	130,175				$ 37			130,138
Foreign currency translation adjustment	(682)											(682)
Net loss attributable to common shareholders of Evolent Health, Inc.	(7,815)												(7,815)
Ending balance (in shares) at Sep. 30, 2022					101,160,000
Ending balance at Sep. 30, 2022	856,138				$ 1,012			1,472,098				(1,044)	(594,805)		(21,123)
Beginning balance (in shares) at Jun. 30, 2022					91,657,000
Beginning balance at Jun. 30, 2022	613,088				$ 916			1,231,005				(782)	(596,928)		(21,123)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	6,992							6,992
Exercise of stock options (in shares)					317,000
Exercise of stock options	2,971				$ 4			2,967
Restricted stock units vested, net of shares withheld for taxes (in shares)					50,000
Restricted stock units vested, net of shares withheld for taxes	(948)				$ 1			(949)
Exchange and conversion of 2024 notes (in shares)					5,394,000
Exchange and conversion of 2024 notes	101,999				$ 54			101,945
Shares issued for acquisition (in shares)					3,742,000
Shares issued for acquisition	130,175				$ 37			130,138
Foreign currency translation adjustment	(262)											(262)
Net loss attributable to common shareholders of Evolent Health, Inc.	2,123												2,123
Ending balance (in shares) at Sep. 30, 2022					101,160,000
Ending balance at Sep. 30, 2022	$ 856,138				$ 1,012			1,472,098				(1,044)	(594,805)		(21,123)
Beginning balance (in shares) at Dec. 31, 2022	0
Beginning balance at Dec. 31, 2022	$ 0
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of series A preferred stock, net of issuance costs (in shares)	175,000
Issuance of series A preferred stock, net of issuance costs	$ 168,000
Net loss attributable to common shareholders of Evolent Health, Inc.	$ 7,606
Ending balance (in shares) at Sep. 30, 2023	175,000
Ending balance at Sep. 30, 2023	$ 175,606
Beginning balance (in shares) at Dec. 31, 2022	101,500,558				101,501,000
Beginning balance at Dec. 31, 2022	$ 859,417				$ 1,015			1,486,857				(1,178)	(606,154)		(21,123)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	29,898							29,898
Exercise of stock options (in shares)					1,106,000
Exercise of stock options	9,183				$ 11			9,172
Restricted stock units vested, net of shares withheld for taxes (in shares)					575,000
Restricted stock units vested, net of shares withheld for taxes	(10,373)				$ 5			(10,378)
Stock units vested, net of shares withheld for taxes (in shares)						202,000	760,000
Stock units vested, net of shares withheld for taxes		$ (3,975)	$ 0			$ 2	$ 8		$ (3,977)	$ (8)
Class A common stock issued for payment of earn-outs (in shares)					877,000
Class A common stock issued for payment of earn-outs	28,551				$ 9			28,542
Exchange and conversion of 2024 notes (in shares)					1,294,000
Exchange and conversion of 2024 notes	23,073				$ 13			23,060
Shares issued for acquisition (in shares)					8,475,000
Shares issued for acquisition	261,271				$ 85			261,186
Foreign currency translation adjustment	(87)											(87)
Net loss attributable to common shareholders of Evolent Health, Inc.	$ (100,865)							(21,236)					(79,629)
Ending balance (in shares) at Sep. 30, 2023	114,789,963				114,790,000
Ending balance at Sep. 30, 2023	$ 1,096,093				$ 1,148			1,803,116				(1,265)	(685,783)		(21,123)
Beginning balance (in shares) at Jun. 30, 2023	175,000
Beginning balance at Jun. 30, 2023	$ 172,829
Increase (Decrease) in Temporary Equity [Roll Forward]
Net loss attributable to common shareholders of Evolent Health, Inc.	$ 2,777
Ending balance (in shares) at Sep. 30, 2023	175,000
Ending balance at Sep. 30, 2023	$ 175,606
Beginning balance (in shares) at Jun. 30, 2023					113,083,000
Beginning balance at Jun. 30, 2023	1,093,219				$ 1,131			1,774,784				(1,114)	(660,459)		(21,123)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	10,222							10,222
Exercise of stock options (in shares)					330,000
Exercise of stock options	4,529				$ 3			4,526
Restricted stock units vested, net of shares withheld for taxes (in shares)					83,000
Restricted stock units vested, net of shares withheld for taxes	(1,603)				$ 1			(1,604)
Exchange and conversion of 2024 notes (in shares)					1,294,000
Exchange and conversion of 2024 notes	23,073				$ 13			23,060
Foreign currency translation adjustment	(151)
Net loss attributable to common shareholders of Evolent Health, Inc.	$ (33,196)							(7,872)					(25,324)
Ending balance (in shares) at Sep. 30, 2023	114,789,963				114,790,000
Ending balance at Sep. 30, 2023	$ 1,096,093				$ 1,148			$ 1,803,116				$ (1,265)	$ (685,783)		$ (21,123)