| Document and Entity Information | Aug. 12, 2021 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001842718 |
| Document Type | 8-K |
| Document Period End Date | Aug. 12, 2021 |
| Entity Registrant Name | INTEGRAL AD SCIENCE HOLDING CORP. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-40557 |
| Entity Tax Identification Number | 83-0731995 |
| Entity Address, Address Line One | 95 Morton St. |
| Entity Address, Address Line Two | 8th Floor |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10014 |
| City Area Code | (646) |
| Local Phone Number | 278-4871 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, $0.001 par value |
| Trading Symbol | IAS |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
