Transactions - Pro Forma Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition, Pro Forma Information, Nonrecurring Adjustments
Revenue		$ 763,624	$ 679,323
Net loss		(69,337)	(80,990)
Net loss attributable to non-controlling interests		(3,554)	(11,544)
Net loss attributable to common shareholders of Evolent Health, Inc.		$ (65,783)	$ (69,446)
Net loss available to common shareholders, basic (in dollars per share)		$ (0.85)	$ (1.08)
Net loss available to common shareholders, diluted (in dollars per share)	$ (3.66)	$ (0.85)	$ (1.08)