| Cover Page | Nov. 05, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Nov. 5, 2020 |
| Entity Registrant Name | AAON, INC. |
| Entity Incorporation, State or Country Code | NV |
| Entity File Number | 0-18953 |
| Entity Tax Identification Number | 87-0448736 |
| Entity Address, Address Line One | 2425 South Yukon Ave., |
| Entity Address, City or Town | Tulsa, |
| Entity Address, State or Province | OK |
| Entity Address, Postal Zip Code | 74107 |
| City Area Code | 918 |
| Local Phone Number | 583-2266 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | AAON |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000824142 |
| Amendment Flag | false |
