Note 10 - Asset Retirement Obligations (Details Textual)	6 Months Ended
Feb. 25, 2017
Minimum [Member]
Asset Retirement Obligation, Remaining Lives	1 year
Maximum [Member]
Asset Retirement Obligation, Remaining Lives	27 years

This element describes the minimum years the Company will discount the liability of estimated future costs to decommission one of its facilities.

No definition available.

Name:	unf_AssetRetirementObligationRemainingLives
Namespace Prefix:	unf_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration