Name:	unf_AccrualForEnvironmentalLossContingenciesEffectOfInflation
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Accrual for environmental loss contingencies, net of estimated insurance proceeds, total.

No definition available.

Name:	unf_AccrualForEnvironmentalLossContingenciesNetOfEstimatedInsuranceProceeds
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The portion of the estimated aggregate undiscounted amount of the accrual for environmental loss contingencies that is expected to be paid, net of estimated insurance proceeds expected to be received, after the fifth year of the balance sheet date.

No definition available.

Name:	unf_AccrualForEnvironmentalLossContingenciesUndiscountedDueAfterFifthYearNetOfEstimatedInsuranceProceeds
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

No definition available.

Name:	unf_AccrualForEnvironmentalLossContingenciesUndiscountedDueInFiveYearsNetOfEstimatedInsuranceProceeds
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

No definition available.

Name:	unf_AccrualForEnvironmentalLossContingenciesUndiscountedDueInFourYearsNetOfEstimatedInsuranceProceeds
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

No definition available.

Name:	unf_AccrualForEnvironmentalLossContingenciesUndiscountedDueInThreeYearsNetOfEstimatedInsuranceProceeds
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

No definition available.

Name:	unf_AccrualForEnvironmentalLossContingenciesUndiscountedDueInTwoYearsNetOfEstimatedInsuranceProceeds
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

No definition available.

Name:	unf_AccrualForEnvironmentalLossContingenciesUndiscountedDueWithinOneYearNetOfEstimatedInsuranceProceeds
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of discount applied to the future cost of environmental remediation to present value.

No definition available.

Name:	unf_EnvironmentalLiabilitiesChangesInDiscountRates
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of interest accretion expense recognized during the period that is associated with environmental remediation costs. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability.

No definition available.

Name:	unf_EnvironmentalLiabilitiesInterestAccretion
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Name:	unf_EstimatedCostsCurrentDollarsAbstract
Namespace Prefix:	unf_
Data Type:	xbrli:stringItemType
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

Name:	unf_EstimatedInsuranceProceedsAbstract
Namespace Prefix:	unf_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The estimated aggregate undiscounted amount of the estimated insurance proceeds accrual for environmental loss contingencies as of the balance sheet date.

No definition available.

Name:	unf_EstimatedInsuranceProceedsForEnvironmentalLossContingenciesGross
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The portion of the estimated aggregate undiscounted amount of the insurance proceeds for environmental loss contingencies that is expected to be received after the fifth year of the balance sheet date.

No definition available.

Name:	unf_EstimatedInsuranceProceedsForEnvironmentalLossContingenciesUndiscountedDueAfterFifthYear
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The portion of the estimated aggregate undiscounted amount of the insurance proceeds for environmental loss contingencies that is expected to be received within five years of the balance sheet date.

No definition available.

Name:	unf_EstimatedInsuranceProceedsForEnvironmentalLossContingenciesUndiscountedDueInFifthYear
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The portion of the estimated aggregate undiscounted amount of the insurance proceeds for environmental loss contingencies that is expected to be received within four years of the balance sheet date.

No definition available.

Name:	unf_EstimatedInsuranceProceedsForEnvironmentalLossContingenciesUndiscountedDueInFourthYear
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The portion of the estimated aggregate undiscounted amount of the insurance proceeds for environmental loss contingencies that is expected to be received within two years of the balance sheet date.

No definition available.

Name:	unf_EstimatedInsuranceProceedsForEnvironmentalLossContingenciesUndiscountedDueInSecondYear
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The portion of the estimated aggregate undiscounted amount of the insurance proceeds for environmental loss contingencies that is expected to be received within three years of the balance sheet date.

No definition available.

Name:	unf_EstimatedInsuranceProceedsForEnvironmentalLossContingenciesUndiscountedDueInThirdYear
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The portion of the estimated aggregate undiscounted amount of the insurance proceeds for environmental loss contingencies that is expected to be received within one year of the balance sheet date.

No definition available.

Name:	unf_EstimatedInsuranceProceedsForEnvironmentalLossContingenciesUndiscountedDueWithinOneYear
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

This element represents the number of insurance companies the Company is entitled to receive legal settlements as reimbursements for environmental remediation costs.

No definition available.

Name:	unf_InsuranceCompaniesPayingLegalSettlements
Namespace Prefix:	unf_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Name:	unf_NetAnticipatedCostsAbstract
Namespace Prefix:	unf_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

This element represents the number of sites related to former operations that are subject to remediation of certain hazardous or toxic substances.

No definition available.

Name:	unf_NumberOfSitesRelatedToFormerOperationsWithEnvironmentalIssues
Namespace Prefix:	unf_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Recorded amount of the individual components comprising the asset for insurance recoveries related to environmental remediation obligations.

No definition available.

Name:	unf_RecordedInsuranceEnvironmentalRecoveriesAmount
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Maximum risk-free rate of interest used to discount the remediation costs. A risk-free rate represents the interest that an investor would expect from an absolutely risk-free investment over a given period of time.

No definition available.

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

This element represent the minimum risk-free rate of interest used to discount the remediation costs. A risk-free rate represents the interest that an investor would expect from an absolutely risk-free investment over a given period of time.

No definition available.

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

Total costs accrued as of the balance sheet date for environmental loss contingencies.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 410

-SubTopic 30

-Section 50

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 25

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6395460&loc=d3e13647-108346

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

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 96-1

-Paragraph 161

-Subparagraph a

-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 Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 9

-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 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14326-108349

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

The amount of imputed interest necessary to reduce (reconcile) the estimated aggregate undiscounted amount of the accrual for environmental loss contingencies to the present value recognized on the balance sheet (if the accrual qualifies for discounting).

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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 5

-Section Y

-Paragraph Question 1

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 5.Y.Q1)

-URI http://asc.fasb.org/extlink&oid=6572457&loc=d3e149879-122751

Name:	us-gaap_AccrualForEnvironmentalLossContingenciesDiscount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The estimated aggregate undiscounted amount of the accrual for environmental loss contingencies as of the balance sheet date.

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

Present value of the estimated aggregate accrual for environmental loss contingencies as of the balance sheet date (if the accrual qualifies for discounting).

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 410

-SubTopic 30

-Section 50

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 410

-SubTopic 30

-Section 35

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=6536425&loc=d3e12798-110857

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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 5

-Section Y

-Paragraph Question 1

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

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 96-1

-Paragraph 161, 132

-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 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 5.Y.Q1)

-URI http://asc.fasb.org/extlink&oid=6572457&loc=d3e149879-122751

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

The aggregate amount disbursed during the reporting period to settle environmental loss contingencies.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 5.Y.Q2)

-URI http://asc.fasb.org/extlink&oid=6572457&loc=d3e149879-122751

Name:	us-gaap_AccrualForEnvironmentalLossContingenciesPayments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

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

The portion of the estimated aggregate undiscounted amount of the accrual for environmental loss contingencies that is expected to be paid after the fifth year after the balance sheet date.

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

The portion of the estimated aggregate undiscounted amount of the accrual for environmental loss contingencies that is expected to be paid in the fifth year after the balance sheet date.

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

The portion of the estimated aggregate undiscounted amount of the accrual for environmental loss contingencies that is expected to be paid in the fourth year after the balance sheet date.

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

The portion of the estimated aggregate undiscounted amount of the accrual for environmental loss contingencies that is expected to be paid in the second year after the balance sheet date.

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

The portion of the estimated aggregate undiscounted amount of the accrual for environmental loss contingencies that is expected to be paid in the third year after the balance sheet date.

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

The portion of the estimated aggregate undiscounted amount of the accrual for environmental loss contingencies that is expected to be paid within one year of the balance sheet date.

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

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

The designation of funds furnished by a borrower to a lender to assure future payments of the borrower's real estate taxes and insurance obligations with respect to a mortgaged property. Escrow deposits may be made for a variety of other purposes such as earnest money and contingent payments. This element excludes replacement reserves which are an escrow separately provided for within the US GAAP taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.10)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Name:	us-gaap_EscrowDeposit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The net proceeds or assets obtained in excess of (less than) the net carrying amount of assets recorded, or assets distributed and liabilities assumed less than (in excess of) estimated litigation liability extinguished, in settlement of a litigation matter. Represents (for other than an insurance entity in its normal claims settlement process), the amount of income (expense) recognized in the period to settle pending or threatened litigation and insurance claims.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 9, 10, 11, 12

-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 450

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14326-108349

Name:	us-gaap_GainLossRelatedToLitigationSettlement
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The effective date of a duly executed litigation settlement agreement.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 9

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14557-108349

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 9, 10, 11, 12

-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 Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14326-108349

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14435-108349

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

Cash received for the settlement of litigation during the current period.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 27

-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 230

-SubTopic 10

-Section 45

-Paragraph 25

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3536-108585