| Document and Entity Information Document | Feb. 26, 2020 |
| Document [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Feb. 26, 2020 |
| Entity Registrant Name | Graco Inc. |
| Entity Incorporation, State or Country Code | MN |
| Entity File Number | 001-09249 |
| Entity Tax Identification Number | 41-0285640 |
| Entity Address, Address Line One | 88 – 11th Avenue Northeast |
| Entity Address, City or Town | Minneapolis, |
| Entity Address, State or Province | MN |
| Entity Address, Postal Zip Code | 55413 |
| City Area Code | (612) |
| Local Phone Number | 623-6000 |
| 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 | GGG |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000042888 |
| Amendment Flag | false |
