| Cover Cover | May 07, 2020 | Oct. 29, 2019 |
| Cover [Abstract] | ||
| Document Type | 8-K | |
| Document Period End Date | Apr. 29, 2021 | |
| Entity Registrant Name | EXLSERVICE HOLDINGS, INC. | |
| Entity Incorporation, State or Country Code | DE | |
| Entity File Number | 001-33089 | |
| Entity Tax Identification Number | 82-0572194 | |
| Entity Address, Address Line One | 320 Park Avenue, | |
| Entity Address, Address Line Two | 29th Floor, | |
| Entity Address, City or Town | New York, | |
| Entity Address, State or Province | NY | |
| Entity Address, Postal Zip Code | 10022 | |
| City Area Code | 212 | |
| Local Phone Number | 277-7100 | |
| Written Communications | false | |
| Soliciting Material | false | |
| Pre-commencement Tender Offer | false | |
| Pre-commencement Issuer Tender Offer | false | |
| Entity Emerging Growth Company | false | |
| Title of 12(b) Security | Common Stock, $0.001 par value per share | |
| Trading Symbol | EXLS | |
| Security Exchange Name | NASDAQ | |
| Amendment Flag | false | |
| Entity Central Index Key | 0001297989 |
