Stock Dividend (Details Textual)	9 Months Ended
Sep. 29, 2012	May 15, 2012
Stock Dividend (Textual) [Abstract]
Stock Dividend, declared date	May 15, 2012
Stock dividend ratio upon stock split		Two-for-one
Stock dividend record date	Jun. 01, 2012
Recorded date of shares distributed to shareholders	Jun. 15, 2012

Name:	dorm_StockDividendTextualAbstract
Namespace Prefix:	dorm_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Stockholders stock dividend note stock dividend ratio upon stock split.

+ References

No definition available.

+ Details

Name:	dorm_StockholdersStockDividendRatioUponStockSplit
Namespace Prefix:	dorm_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	instant

- Definition

Date the declared dividend will be paid, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_DividendPayableDateToBePaidDayMonthAndYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the dividend to be paid was declared, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 32

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Name:	us-gaap_DividendsPayableDateDeclaredDayMonthAndYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

Name:	us-gaap_DividendsPayableDateOfRecordDayMonthAndYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration