Subsequent Event - Additional Information (Detail) (Revolving Credit Facility [Member])	3 Months Ended
Mar. 28, 2015
Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Credit facility expiration date	2017-06

Line of credit facility expiration month and year.

No definition available.

Name:	dorm_LineOfCreditFacilityExpirationMonthAndYear
Namespace Prefix:	dorm_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	duration