| Document and Entity Information | Feb. 24, 2020 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0000868780 |
| Document Type | 8-K |
| Document Period End Date | Feb. 24, 2020 |
| Entity Registrant Name | Dorman Products, Inc. |
| Entity Incorporation State Country Code | PA |
| Entity File Number | 000-18914 |
| Entity Tax Identification Number | 23-2078856 |
| Entity Address, Address Line One | 3400 East Walnut Street |
| Entity Address, City or Town | Colmar |
| Entity Address, State or Province | PA |
| Entity Address, Postal Zip Code | 18915 |
| City Area Code | (215) |
| Local Phone Number | 997-1800 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, $0.01 Par Value |
| Trading Symbol | DORM |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
