Employee Benefit Plans - Schedule of Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 29, 2026	Aug. 30, 2025	Aug. 31, 2024
UniFirst Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 74	$ 73	$ 74
Interest cost	133	148	159
Expected return on assets	(72)	(91)	(90)
Amortization of prior service cost	21	21	21
Amortization of actuarial gain	0	0	0
Other events	47	(10)	0
Net periodic benefit cost	203	141	164
SERP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	274	390	405
Interest cost	1,224	1,239	1,255
Expected return on assets	0	0	0
Amortization of prior service cost	0	0	0
Amortization of actuarial gain	(322)	(41)	(116)
Other events	0	0	0
Net periodic benefit cost	$ 1,176	$ 1,588	$ 1,544