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Summary of Significant Accounting Policies - Estimated Useful Lives by Major Asset (Detail) | 12 Months Ended
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Dec. 30, 2017
Minimum [Member] |
Property, Plant and Equipment [Line Items] |
Estimated useful life of Property, Plant and Equipment | 3 years
Minimum [Member] | Buildings and Building Improvements [Member] |
Property, Plant and Equipment [Line Items] |
Estimated useful life of Property, Plant and Equipment | 10 years
Minimum [Member] | Machinery, Equipment and Tooling [Member] |
Property, Plant and Equipment [Line Items] |
Estimated useful life of Property, Plant and Equipment | 3 years
Minimum [Member] | Software and Computer Equipment [Member] |
Property, Plant and Equipment [Line Items] |
Estimated useful life of Property, Plant and Equipment | 3 years
Minimum [Member] | Furniture, Fixtures and Leasehold Improvements [Member] |
Property, Plant and Equipment [Line Items] |
Estimated useful life of Property, Plant and Equipment | 3 years
Maximum [Member] |
Property, Plant and Equipment [Line Items] |
Estimated useful life of Property, Plant and Equipment | 39 years
Maximum [Member] | Buildings and Building Improvements [Member] |
Property, Plant and Equipment [Line Items] |
Estimated useful life of Property, Plant and Equipment | 39 years
Maximum [Member] | Machinery, Equipment and Tooling [Member] |
Property, Plant and Equipment [Line Items] |
Estimated useful life of Property, Plant and Equipment | 10 years
Maximum [Member] | Software and Computer Equipment [Member] |
Property, Plant and Equipment [Line Items] |
Estimated useful life of Property, Plant and Equipment | 10 years
Maximum [Member] | Furniture, Fixtures and Leasehold Improvements [Member] |
Property, Plant and Equipment [Line Items] |
Estimated useful life of Property, Plant and Equipment | 15 years

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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_PropertyPlantAndEquipmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingAndBuildingImprovementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=dorm_SoftwareAndComputerEquipmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=dorm_FurnitureFixturesAndLeaseholdImprovementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |