Basis of Presentation and Summary of Significant Accounting Policies (Details) ft² in Thousands	Sep. 24, 2026 ft² store distribution_center design_studio state
Real Estate Properties [Line Items]
Number of states with facilities \| state	39
Number of distribution centers \| distribution_center	5
Warehouse Format Stores
Real Estate Properties [Line Items]
Number of stores \| store	282
Area of facility \| ft²	75
Design Studio
Real Estate Properties [Line Items]
Number of stores \| design_studio	5

The number of distribution centers owned or operated by the entity.

No definition available.

Name:	fnd_NumberOfDistributionCenters
Namespace Prefix:	fnd_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Area of a real estate property.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 275
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482861/275-10-50-2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 970
-SubTopic 360
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-28(Column A)(Footnote 2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478979/970-360-S99-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 970
-SubTopic 360
-Name Accounting Standards Codification
-Section 30
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478150/970-360-30-2

+ Details

Name:	us-gaap_AreaOfRealEstateProperty
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of states the entity operates in as of the balance sheet date.

+ References

+ Details

Name:	us-gaap_NumberOfStatesInWhichEntityOperates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of stores.

+ References

+ Details

Name:	us-gaap_NumberOfStores
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- 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

+ Details

Name:	us-gaap_RealEstatePropertiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=fnd_WarehouseFormatStoreMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=fnd_DesignStudioMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: