Document and Entity Information - shares	6 Months Ended
	Jun. 29, 2019	Jul. 29, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 29, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Trading Symbol	DORM
Entity Registrant Name	Dorman Products, Inc.
Entity Central Index Key	0000868780
Current Fiscal Year End Date	--12-29
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity File Number	0-18914
Entity Tax Identification Number	232078856
Entity Address, Address Line One	3400 East Walnut Street
Entity Address, City or Town	Colmar
Entity Address, State or Province	Pennsylvania
Entity Address, Postal Zip Code	18915
City Area Code	215
Local Phone Number	997-1800
Entity Common Stock, Shares Outstanding		32,785,889