Employee Benefit Plans - Schedule of Amounts Recorded in Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Aug. 29, 2026	Aug. 30, 2025
UniFirst Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Deferred tax assets (liabilities)	$ 48	$ 4
Accrued liabilities	710	530
Accumulated other comprehensive (loss) income	(141)	(11)
SERP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Deferred tax assets (liabilities)	(1,677)	(1,388)
Accrued liabilities	21,855	23,479
Accumulated other comprehensive (loss) income	$ 4,969	$ 4,071