| Document and Entity Information | Oct. 01, 2021 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001861795 |
| Document Type | 8-K |
| Document Period End Date | Oct. 1, 2021 |
| Entity Registrant Name | Definitive Healthcare Corp. |
| Entity File Number | 1-40815 |
| Entity Incorporation State Country Code | DE |
| Entity Tax Identification Number | 86-3988281 |
| Entity Address, Address Line One | 550 Cochituate Rd |
| Entity Address, City or Town | Framingham |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 01701 |
| City Area Code | (508) |
| Local Phone Number | 720-4224 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Class A Common Stock, $0.001 par value |
| Trading Symbol | DH |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
