Basis of presentation.

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Business process improvement cost.

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Measurable costs associated with product losses.

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Additional information about the entity or its reportable segments that may contribute to an understanding of the enterprise.

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Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

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Basis of Presentation - Additional Information (Detail) $ in Thousands	3 Months Ended			4 Months Ended	6 Months Ended
	Jul. 18, 2026 USD ($)	Jan. 03, 2026 USD ($)	Jul. 12, 2025 USD ($)	Apr. 19, 2025 USD ($)	Jul. 18, 2026 USD ($) Segment	Jul. 12, 2025 USD ($)
Basis of Presentation [Line Items]
Number of operating segments \| Segment					1
Segment reporting, description					The company has identified two operating segments based on how business activities are managed and evaluated, legacy Flowers Foods and Simple Mills. Simple Mills qualifies as an operating segment as it meets the criteria for being a business and has discrete financial information available that is regularly reviewed by the chief executive officer (the "CEO"), who is the chief operating decision maker (the "CODM"), to assess the performance and allocate resources. As Simple Mills shares similar economic characteristics with legacy Flowers Foods, we aggregate Simple Mills and legacy Flowers Foods as one operating segment for the purpose of determining our one reportable segment.
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]					srt:ChiefExecutiveOfficerMember
Number of reportable segments \| Segment					1
Identifiable and measurable costs		$ 2,700
Reimbursement received	$ 2,000
Investment in unconsolidated affiliate	1,481	1,481			$ 1,481
Asset impairment charges and equipment relocation costs					0	$ 5,495
Business Process Improvement Cost	1,010		$ 471		2,251	$ 1,362
Spare parts and supplies	926,854	$ 952,725			926,854
Bailey Street Bakery
Basis of Presentation [Line Items]
Severance costs				$ 1,300
Asset impairment charges and equipment relocation costs				$ 6,100
Spare Parts and Supplies
Basis of Presentation [Line Items]
Spare parts and supplies	$ 102,200				$ 102,200