Summary of AOCI Exclusive of Reclassification (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jan. 03, 2026	Dec. 28, 2024	Dec. 30, 2023
Accumulated Other Comprehensive Income Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI, Derivative instruments net of tax	$ (3,186)	$ 5,404	$ (2,951)
Amount of Gain (Loss) Recognized in AOCI, Current year, before tax	(5,922)	188	628
Amount of Gain (Loss) Recognized in AOCI, Current year, net of tax	(7,627)	5,545	(2,480)
Derivative Instruments
Accumulated Other Comprehensive Income Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI, Derivative instruments before tax	(4,249)	7,206	(3,934)
Amount of Gain (Loss) Recognized in AOCI, Current year, tax benefit (expense)	1,063	(1,802)	983
Amount of Gain (Loss) Recognized in AOCI, Derivative instruments net of tax	(3,186)	5,404	(2,951)
Amount of Gain (Loss) Recognized in AOCI, Current year, net of tax	(3,186)	5,404	(2,951)
Current Year Actuarial Loss
Accumulated Other Comprehensive Income Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI, Current year, before tax	(2,959)	188	628
Pension and postretirement plans, prior service credits
Accumulated Other Comprehensive Income Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI, Current year, before tax	(2,963)
Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI, Current year, tax expense	1,481	(47)	(157)
Amount of Gain (Loss) Recognized in AOCI, Current year, net of tax	(4,441)	141	471
Interest Rate Contracts
Accumulated Other Comprehensive Income Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI, Current year, net of tax	3,160	5,758
Interest Rate Contracts \| Derivative Instruments
Accumulated Other Comprehensive Income Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI, Derivative instruments before tax	4,213	7,679
Commodity Contract
Accumulated Other Comprehensive Income Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI, Current year, net of tax	(6,346)	(354)	(2,951)
Commodity Contract \| Derivative Instruments
Accumulated Other Comprehensive Income Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI, Derivative instruments before tax	$ (8,462)	$ (473)	$ (3,934)

FLOWERS FOODS INC 10-K