| Document and Entity Information | Dec. 21, 2020 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001628908 |
| Document Type | 8-K |
| Document Period End Date | Dec. 21, 2020 |
| Entity Registrant Name | Evolent Health, Inc. |
| Entity Incorporation State 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 |
| Entity Address, Postal Zip Code | 22203 |
| City Area Code | (571) |
| Local Phone Number | 389-6000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | 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 |
