XML 28 R52.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Asset Retirement Obligations (Details) (USD $) In Thousands, unless otherwise specified | 12 Months Ended
--- | ---
Aug. 25, 2012 | Aug. 27, 2011 | Aug. 28, 2010
Asset Retirement Obligations [Abstract] |  |  |
Estimated impact of inflation per year (in hundredths) | 3.00% |  |
Credit-adjusted risk-free rates, minimum (in hundredths) | 7.00% |  |
Credit-adjusted risk-free rates, maximum (in hundredths) | 7.50% |  |
Range of years discount for estimated future costs to decommission its nuclear laundry facilities, minimum years (in years) | 1Y |  |
Range of years discount for estimated future costs to decommission its nuclear laundry facilities, maximum years (in years) | 32Y |  |
Rollforward of asset retirement liabilities [Abstract] |  |  |
Beginning balance | $ 9,488 | $ 8,899 |
Accretion expense | 632 | 589 | 568
Ending balance | $ 10,120 | $ 9,488 | $ 8,899

X
- Definition This element represents the maximum 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. + References No definition available. + Details
Name: | unf_CreditAdjustedRiskFreeRatesMaximumRate
Namespace Prefix: | unf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition 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. + References No definition available. + Details
Name: | unf_CreditAdjustedRiskFreeRatesMinimumRate
Namespace Prefix: | unf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition This element represents the percentage added to estimated current cost of decommissioning one of the Company's facilities based on future estimated inflation rate. + References No definition available. + Details
Name: | unf_EstimatedImpactOfInflationPerYear
Namespace Prefix: | unf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition This element describes the maximum years the Company will discount the liability of estimated future costs to decommission one of its facilities. + References No definition available. + Details
Name: | unf_RangeOfYearsDiscountForEstimatedFutureCostsToDecommissionItsNuclearLaundryFacilitiesMaximumYears
Namespace Prefix: | unf_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition This element describes the minimum years the Company will discount the liability of estimated future costs to decommission one of its facilities. + References No definition available. + Details
Name: | unf_RangeOfYearsDiscountForEstimatedFutureCostsToDecommissionItsNuclearLaundryFacilitiesMinimumYears
Namespace Prefix: | unf_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition 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. + References 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 + Details
Name: | us-gaap_AssetRetirementObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

X
- Definition 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. + References 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 + Details
Name: | us-gaap_AssetRetirementObligationAccretionExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_AssetRetirementObligationRollForwardAnalysisRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration