| Document and Entity Information | Aug. 08, 2023 |
| Cover [Abstract] | |
| Entity Registrant Name | AZEK Co Inc. |
| Amendment Flag | false |
| Entity Central Index Key | 0001782754 |
| Document Type | 8-K |
| Document Period End Date | Aug. 08, 2023 |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-39322 |
| Entity Tax Identification Number | 90-1017663 |
| Entity Address, Address Line One | 1330 W Fulton Street 350 |
| Entity Address, City or Town | Chicago |
| Entity Address, State or Province | IL |
| Entity Address, Postal Zip Code | 60607 |
| City Area Code | (877) |
| Local Phone Number | 275-2935 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Class A Common Stock, par value $0.001 per share |
| Trading Symbol | AZEK |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
