Name:	unf_CreditAdjustedRiskFreeRatesMaximumRate
Namespace Prefix:	unf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

This element represents the minimum rate that a liability is discounted, using a credit-adjusted risk-free rate. Credit-adjusting the risk-free rate means adding to the Treasury rates some amount of additional interest-rate basis points to reflect the fact that companies might default on their debt obligations.

No definition available.

Name:	unf_CreditAdjustedRiskFreeRatesMinimumRate
Namespace Prefix:	unf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

This element represents the percentage added to estimated current cost of decommissioning one of the Company's facilities based on future estimated inflation rate.

No definition available.

Name:	unf_EstimatedImpactOfInflationPerYear
Namespace Prefix:	unf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

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

No definition available.

Name:	unf_RangeOfYearsDiscountForEstimatedFutureCostsToDecommissionItsNuclearLaundryFacilitiesMaximumYears
Namespace Prefix:	unf_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

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_RangeOfYearsDiscountForEstimatedFutureCostsToDecommissionItsNuclearLaundryFacilitiesMinimumYears
Namespace Prefix:	unf_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 143

-Paragraph 3, 10, 22

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 410

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Asset Retirement Obligation

-URI http://asc.fasb.org/extlink&oid=6505190

Name:	us-gaap_AssetRetirementObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_AssetRetirementObligationAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 410

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (c)(3)

-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 143

-Paragraph 13, 14

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 143

-Paragraph 22

-Subparagraph c(3)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 410

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6392676&loc=d3e7480-110848