| Document and Entity Information | Dec. 08, 2021 |
| Document And Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Dec. 8, 2021 |
| Entity Registrant Name | CVENT HOLDING CORP. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-39709 |
| Entity Tax Identification Number | 98-1560055 |
| Entity Address, Address Line One | 1765 Greensboro Station Place |
| Entity Address, Address Line Two | 7th Floor |
| Entity Address, City or Town | Tysons |
| Entity Address, State or Province | VA |
| Entity Address, Postal Zip Code | 22102 |
| City Area Code | 703 |
| Local Phone Number | 226-3500 |
| Entity Information, Former Legal or Registered Name | DRAGONEER GROWTH OPPORTUNITIES CORP. II |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, $0.0001 par value per share |
| Trading Symbol | CVT |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Current Fiscal Year End Date | --12-31 |
| Amendment Flag | false |
| Entity Central Index Key | 0001827075 |
| Former Address [Member] | |
| Document And Entity Information [Line Items] | |
| Entity Address, Address Line One | One Letterman Drive |
| Entity Address, Address Line Two | Building D |
| Entity Address, Address Line Three | Suite M500 |
| Entity Address, City or Town | San Francisco |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94129 |
