Business combination contingent cash consideration.

No definition available.

Name:	dorm_BusinessCombinationContingentCashConsideration
Namespace Prefix:	dorm_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

Business combination contingent consideration maximum cash payment.

+ References

No definition available.

+ Details

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Namespace Prefix:	dorm_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

Business combination sales thresholds achievement maturity date.

+ References

No definition available.

+ Details

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

- Definition

Payments for working capital and other purchase price adjustments.

+ References

No definition available.

+ Details

Name:	dorm_PaymentsForWorkingCapitalAndOtherPurchasePriceAdjustments
Namespace Prefix:	dorm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Valuation of finite lived intangible assets cash flows discounted rate.

+ References

No definition available.

+ Details

Name:	dorm_ValuationOfFiniteLivedIntangibleAssetsCashFlowsDiscountedRate
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_BusinessAcquisitionLineItems
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477

+ Details

Name:	us-gaap_BusinessCombinationConsiderationTransferred1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow associated with the acquisition of business during the period (for example, cash that was held by the acquired business).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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- Details

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- Details

Name:	us-gaap_BusinessAcquisitionAxis=dorm_MASAutomotiveDistributionIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_SellingGeneralAndAdministrativeExpensesMember
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Business Acquisitions and Investments - Additional Information (Detail) - USD ($)		3 Months Ended	6 Months Ended
	Oct. 26, 2017	Jun. 30, 2018	Jun. 30, 2018
Minimum [Member]
Business Acquisition [Line Items]
Cash flows discounted at rates	15.00%
Maximum [Member]
Business Acquisition [Line Items]
Cash flows discounted at rates	17.00%
MAS Automotive Distribution Inc [Member]
Business Acquisition [Line Items]
Business acquisition, percentage of outstanding stock acquired	100.00%
Business acquisition, total purchase price consideration	$ 67,223,000
Business acquisition, cash acquired	3,300,000
Net sales, included in consolidated statement of operations			$ 20,200,000
Estimated contingent payments	7,982,000		8,000,000
Business combination maximum contingent consideration payment	$ 11,700,000
Business combination sales thresholds achievement maturity date	2020-12
Payment to former shareholder		$ 1,500,000
MAS Automotive Distribution Inc [Member] \| Selling, General and Administrative Expeses [Member]
Business Acquisition [Line Items]
Estimated contingent payments			$ 200,000