Document and Entity Information - shares	3 Months Ended
	Mar. 27, 2021	Apr. 22, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 27, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Trading Symbol	DORM
Title of 12(b) Security	Common stock, par value $0.01 per share
Security Exchange Name	NASDAQ
Entity Registrant Name	Dorman Products, Inc.
Entity Central Index Key	0000868780
Current Fiscal Year End Date	--12-26
Entity Current Reporting Status	Yes
Entity Interactive Data Current	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 Incorporation, State or Country Code	PA
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
Entity Common Stock, Shares Outstanding		32,082,579
Document Quarterly Report	true
Document Transition Report	false