| Cover | Sep. 29, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Sep. 29, 2020 |
| Entity Registrant Name | Evolent Health, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-37415 |
| Entity Tax Identification Number | 32-0454912 |
| Entity Address, Address Line One | 800 N. Glebe Road |
| Entity Address, Address Line Two | Suite 500 |
| Entity Address, City or Town | Arlington |
| Entity Address, State or Province | VA |
| City Area Code | 571 |
| Local Phone Number | 389-6000 |
| Entity Address, Postal Zip Code | 22203 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Class A Common Stock of Evolent Health, Inc., par value $0.01 per share |
| Trading Symbol | EVH |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Amendment Flag | false |
| Entity Central Index Key | 0001628908 |
