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Balance Type:	debit
Period Type:	duration

- Details

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

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
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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 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

Reference 3: 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

Name:	us-gaap_AccrualForEnvironmentalLossContingencies
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The Increase or Decrease in the accrual for environmental loss in the period from revisions in estimates to existing obligations. The amount does not relate to changes in the environmental accrual related to business acquisitions or divestitures, or to currency movements.

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=27011672&loc=d3e149879-122751

Name:	us-gaap_AccrualForEnvironmentalLossContingenciesIncreaseDecreaseForRevisionInEstimates
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Period Type:	duration

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