| Cover | Oct. 28, 2020 |
| Document Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Oct. 28, 2020 |
| Entity Registrant Name | PLEXUS CORP. |
| Entity Incorporation, State or Country Code | WI |
| Entity File Number | 001-14423 |
| Entity Tax Identification Number | 39-1344447 |
| Entity Address, Address Line One | One Plexus Way |
| Entity Address, City or Town | Neenah |
| Entity Address, State or Province | WI |
| Entity Address, Postal Zip Code | 54957 |
| City Area Code | 920 |
| Local Phone Number | 969-6000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.01 par value |
| Trading Symbol | PLXS |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000785786 |
| Amendment Flag | false |
