Revenue Recognition - Narrative (Details)	3 Months Ended
Nov. 30, 2024	Nov. 25, 2023
Revenue from Contract with Customer [Abstract]
Percentage of revenues derived from route servicing fees	84.30%	84.40%

Revenue From Contracts With Customers, Percentage Of Revenues From Route Servicing Fees

No definition available.

Name:	unf_RevenueFromContractsWithCustomersPercentageOfRevenuesFromRouteServicingFees
Namespace Prefix:	unf_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration