Employee Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2024	Aug. 26, 2023	Aug. 27, 2022
UniFirst Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 74	$ 73	$ 72
Interest cost	159	147	104
Expected return on assets	$ (90)	$ (101)	$ (118)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent
Amortization of prior service cost	$ 21	$ 21	$ 21
Amortization of net loss			20
Other events		(12)	(10)
Net periodic benefit cost	164	128	89
SERP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	405	486	919
Interest cost	1,255	1,191	928
Amortization of actuarial (gain)/loss	(116)
Amortization of net loss			516
Other events			(855)
Net periodic benefit cost	$ 1,544	$ 1,677	$ 1,508