Employee Benefit Plans - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Aug. 29, 2026	Aug. 30, 2025	Aug. 31, 2024
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions charged to expense under the plan	$ 15.9	$ 15.6	$ 20.3
Other (income) expense	(0.6)	(0.4)	(0.6)
SERP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Amounts charged to expense related to the plan	1.2	1.6	1.7
Accumulated benefit obligations	20.4	21.7
UniFirst Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Amounts charged to expense related to the plan	0.2	0.2	0.2
Accumulated benefit obligations	2.6	3.0
Non-qualified Deferred Compensation Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Amounts charged to expense related to the plan	1.3	1.0	$ 0.8
NQDC plan assets	5.7	4.7
NQDC plan liabilities, current	$ 3.7	$ 2.8