Statement of Comprehensive Income [Abstract] Net income Net Income (Loss) Attributable to Parent Other comprehensive (loss) income: Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent Pension benefit liabilities, net of income taxes Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent Change in fair value of derivatives, net of income taxes Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Derivative financial instruments reclassified to earnings Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax Other comprehensive (loss) income Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value, Measurement Inputs, Disclosure [Text Block] Business Combinations [Abstract] Business Acquisitions Business Combination Disclosure [Text Block] Income Tax Disclosure [Abstract] Effective income tax rate Effective Income Tax Rate Reconciliation, Percent Income Statement [Abstract] Statement [Table] Statement [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Common Stock Common Class A [Member] Class B Common Stock Common Class B [Member] Statement [Line Items] Statement [Line Items] Revenues Revenues Operating expenses: Operating Expenses [Abstract] Cost of revenues Cost of Revenue Selling and administrative expenses Selling, General and Administrative Expense Depreciation and amortization Depreciation, Depletion and Amortization Total operating expenses Costs and Expenses Income from operations Operating Income (Loss) Other (income) expense: Other Income and Expenses [Abstract] Interest expense Interest Expense Interest income Investment Income, Interest Foreign exchange loss (gain) Foreign Currency Transaction Gain (Loss), before Tax Total other (income) expense Nonoperating Income (Expense) Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Provision for income taxes Income Tax Expense (Benefit) Net income Income per share – Basic: Earnings Per Share, Basic [Abstract] Common Stock (in dollars per share) Earnings Per Share, Basic Income per share – Diluted: Earnings Per Share, Diluted [Abstract] Common Stock (in dollars per share) Earnings Per Share, Diluted Income allocated to – Basic: Net Income (Loss) Available to Common Stockholders, Basic [Abstract] Common Stock Net Income (Loss) Available to Common Stockholders, Basic Income allocated to – Diluted: Net Income (Loss) Available to Common Stockholders, Diluted [Abstract] Common Stock Net Income (Loss) Available to Common Stockholders, Diluted Weighted average number of shares outstanding – Basic: Weighted Average Number of Shares Outstanding, Basic [Abstract] Common Stock (in shares) Weighted Average Number of Shares Outstanding, Basic Weighted average number of shares outstanding – Diluted: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Common Stock (in shares) Weighted Average Number of Shares Outstanding, Diluted Dividends per share: Dividends [Abstract] Dividends per share (in dollars per share) Common Stock, Dividends, Per Share, Declared Schedule of Assets or Liabilities Measured at Fair Value on a Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Stockholders' Equity Note [Abstract] Accumulated Other Comprehensive (Loss) Income Comprehensive Income (Loss) Note [Text Block] Accounting Policies [Abstract] Recent Accounting Pronouncements New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Earnings Per Share [Abstract] Schedule of Computation of Basic Earnings Per Share Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table Text Block] Schedule of Computation of Diluted Earnings Per Share Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Table Text Block] Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility Revolving Credit Facility [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Credit Agreement Credit Agreement [Member] Represents the Credit Agreement. Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] LIBOR London Interbank Offered Rate (LIBOR) [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Maturity date Debt Instrument, Maturity Date Basis points Debt Instrument, Basis Spread on Variable Rate Outstanding borrowings Long-term Line of Credit Outstanding letters of credit Letters of Credit Outstanding, Amount Amount available for borrowing Line of Credit Facility, Remaining Borrowing Capacity Schedule of Changes in Components of Accumulated Other Comprehensive (Loss) Income, Net of Tax Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Schedule of Amounts Reclassified From Accumulated Other Comprehensive (Loss) Income, Net of Tax Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Commitments and Contingencies Disclosure [Abstract] Gain Contingencies [Table] Gain Contingencies [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Williamstown, Vermont VERMONT Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Selling and Administrative Expenses Selling, General and Administrative Expenses [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Gain Contingencies [Line Items] Gain Contingencies [Line Items] Number of sites related to former operations Site Contingency, Environmental Remediation Obligations, Number of Sites Number of Sites, Environmental Gain related to environmental litigation settlement Gain (Loss) Related to Litigation Settlement Estimated rate of inflation unf_EstimatedImpactOfInflationPerYear This element represents the percentage added to estimated current cost of decommissioning one of the Company's facilities based on future estimated inflation rate. Risk-free interest rates utilized unf_RiskFreeRatesOfInterestUsedToDiscountRemediationCosts This element represent the 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. Annual proceeds Proceeds from Legal Settlements Balance in escrow account Escrow Deposit Number of Insurance Companies Number of Insurance Companies Number of Insurance Companies Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Other Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Income Taxes Income Tax Disclosure [Text Block] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Customer contracts Customer Contracts [Member] Other intangible assets Other Intangible Assets [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Gross Carrying Amount Finite-Lived Intangible Assets, Gross Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Net Carrying Amount Finite-Lived Intangible Assets, Net Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosures [Table] Derivative Instruments and Hedging Activities Disclosures [Table] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Forward Contracts Forward Contracts [Member] Currency [Axis] Currency [Axis] All Currencies [Domain] All Currencies [Domain] Canadian Dollars Canada, Dollars Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other Long-term Assets Other Noncurrent Assets [Member] Prepaid Expenses and Other Current Assets Prepaid Expenses and Other Current Assets [Member] Derivative Instruments and Hedging Activities Disclosures [Line Items] Derivative Instruments and Hedging Activities Disclosures [Line Items] Number of derivatives entered into to exchange Canadian dollars for U.S. dollars Number of Foreign Currency Derivatives Held Notional value Derivative, Notional Amount Average exchange rate Derivative, Forward Exchange Rate Fair value of the contracts Cash Flow Hedge Derivative Instrument Assets at Fair Value Gain in accumulated other comprehensive (loss) income, net of tax Accumulated Other Comprehensive Income (Loss), Net of Tax Amount reclassified from accumulated other comprehensive (loss) income to revenue related to derivative financial instruments Asset Retirement Obligation Disclosure [Abstract] Asset Retirement Obligations Asset Retirement Obligation Disclosure [Text Block] Inventory Disclosure [Abstract] Inventories Inventory Disclosure [Text Block] Accrual for Environmental Loss Contingencies [Roll Forward] Accrual for Environmental Loss Contingencies [Roll Forward] Beginning balance Accrual for Environmental Loss Contingencies Costs incurred for which reserves had been provided Accrual for Environmental Loss Contingencies, Payments Insurance proceeds Insurance proceeds Recorded amount of the individual components comprising the asset for insurance recoveries related to environmental remediation obligations. Interest accretion Interest accretion Amount of accretion expense recognized in the income statement during the period that is associated with environmental contingencies. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability. Change in discount rates Change in discount rates Amount of discount applied to the future cost of environmental remediation to present value. Ending balance Long-Term Debt Long-term Debt [Text Block] Postemployment Benefits [Abstract] Contributions charged to expense under the plan Defined Contribution Plan, Cost Amounts charged to expense related to the plans Pension Cost (Reversal of Cost) Schedule of Changes in Carrying Amount of Goodwill Schedule of Goodwill [Table Text Block] Schedule of Intangible Assets, Net Schedule of Finite-Lived Intangible Assets [Table Text Block] Raw materials Inventory, Raw Materials, Net of Reserves Work in process Inventory, Work in Process, Net of Reserves Finished goods Inventory, Finished Goods, Net of Reserves Total inventories Inventory, Net Schedule of Components of Consideration Transferred and Final Allocation of Consideration Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Segment Reporting [Abstract] Schedule of Segment Reporting Information Schedule of Segment Reporting Information, by Segment [Table Text Block] Schedule of Changes to Environmental Liabilities Schedule of Environmental Liabilities [Table Text Block] Tabular disclosure of the components of the environmental liabilities as of period end. Schedule of Anticipated Payments and Insurance Proceeds of Currently Identified Environmental Remediation Liabilities Schedule of Environmental Remediation Liabilities [Table Text Block] Tabular disclosure of environmental remediation costs less estimated insurance proceeds including the effects of inflation and discounting the costs to present value. Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Beginning balance Asset Retirement Obligation Accretion expense Asset Retirement Obligation, Accretion Expense Effect of exchange rate changes Asset Retirement Obligation, Foreign Currency Translation Gain (Loss) Change in estimate Asset Retirement Obligation, Revision of Estimate Ending balance Asset Retirement Obligations [Table] Asset Retirement Obligations [Table] Asset Retirement Obligations [Table] Asset Retirement Obligations [Line Items] Asset Retirement Obligations [Line Items] [Line Items] for Asset Retirement Obligations [Table] Remaining lives unf_AssetRetirementObligationRemainingLives This element describes the minimum years the Company will discount the liability of estimated future costs to decommission one of its facilities. Organization, Consolidation and Presentation of Financial Statements [Abstract] Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Statement of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Adjustments to reconcile net income to cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation Depreciation Amortization of intangible assets Amortization of Intangible Assets Amortization of deferred financing costs Amortization of Debt Issuance Costs and Discounts Gain on sale of assets Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Share-based compensation Share-based Compensation Accretion on environmental contingencies Accretion on asset retirement obligations Deferred income taxes Deferred Income Taxes and Tax Credits Changes in assets and liabilities, net of acquisitions: Increase (Decrease) in Operating Capital [Abstract] Receivables, less reserves Increase (Decrease) in Receivables Inventories Increase (Decrease) in Inventories Rental merchandise in service unf_IncreaseDecreaseInRentalMerchandiseInService The net change during the reporting period in the aggregate value of rental merchandise in service, associated with underlying transactions that are classified as operating activities. Prepaid expenses and other current assets and Other assets Increase (Decrease) in Prepaid Expense and Other Assets Accounts payable Increase (Decrease) in Accounts Payable Accrued liabilities Increase (Decrease) in Accrued Liabilities Prepaid and accrued income taxes Increase (Decrease) in Income Taxes Payable Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Acquisition of businesses, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Capital expenditures Payments to Acquire Property, Plant, and Equipment Proceeds from sale of assets Proceeds from Sale of Property, Plant, and Equipment Other Payments for (Proceeds from) Other Investing Activities Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Payments on loans payable and long-term debt Repayments of Long-term Debt Payment of deferred financing costs Payments of Financing Costs Proceeds from exercise of share-based awards, including excess tax benefits Proceeds from Stock Options Exercised Taxes withheld and paid related to net share settlement of equity awards Payments Related to Tax Withholding for Share-based Compensation Payment of cash dividends Payments of Dividends Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations Effect of exchange rate changes Effect of Exchange Rate on Cash and Cash Equivalents Net (decrease) increase in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at end of period Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Actuarial Losses Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member] Pension Benefit Liabilities, Net Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Derivative Financial Instruments, Net Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Total amounts reclassified, net of tax Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent Number of operating segments Number of Operating Segments Number of reporting segments Number of Reportable Segments Net Income Per Share Earnings Per Share [Text Block] Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Table] Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Table] Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items] Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items] As reported - Basic As reported - Basic (in shares) As reported - Basic (in dollars per share) Add: effect of dilutive potential common shares Dilutive Securities, Effect on Basic Earnings Per Share Add: effect of dilutive potential common shares (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Add: Undistributed earnings allocated to unvested participating shares Undistributed Earnings, Diluted Less: Undistributed earnings reallocated to unvested participating shares unf_UndistributedEarningsReallocatedToUnvestedParticipatingShares The earnings that is reallocated to common stock and participating securities to the extent that each security may share in earnings as if all of the earnings for the period had been distributed. Diluted EPS – Common Stock Diluted EPS – Common Stock (in shares) Diluted EPS – Common Stock (in dollars per share) Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table] Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table] Unvested participating shares Unvested Participating Shares [Member] Represents the unvested participating shares. Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Net income available to shareholders Allocation of net income for Basic: Weighted average number of shares for Basic: Earnings per share for Basic: Reconciliation of Asset Retirement Liability Schedule of Asset Retirement Obligations [Table Text Block] Estimated costs – current dollars Accrual for Environmental Loss Contingencies, Fiscal Year Maturity [Abstract] 2017 Accrual for Environmental Loss Contingencies, Undiscounted, Remainder of Fiscal Year 2018 Accrual for Environmental Loss Contingencies, Undiscounted, Second Year 2019 Accrual for Environmental Loss Contingencies, Undiscounted, Third Year 2020 Accrual for Environmental Loss Contingencies, Undiscounted, Fourth Year 2021 Accrual for Environmental Loss Contingencies, Undiscounted, Fifth Year Thereafter Accrual for Environmental Loss Contingencies, Undiscounted, after Fifth Year Total Accrual for Environmental Loss Contingencies, Gross Estimated insurance proceeds Estimated Insurance Proceeds for Environmental Loss Coontingencies, Fiscal Year Maturity [Abstract] Estimated Insurance Proceeds for Environmental Loss Coontingencies, Fiscal Year Maturity [Abstract] 2017 unf_EstimatedInsuranceProceedsForEnvironmentalLossContingenciesUndiscountedRemainderOfFiscalYear The portion of the estimated aggregate undiscounted amount of the insurance proceeds for environmental loss contingencies that is expected to be received within the remainder of the fiscal year. 2018 unf_EstimatedInsuranceProceedsForEnvironmentalLossContingenciesUndiscountedDueInSecondYear 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. 2019 unf_EstimatedInsuranceProceedsForEnvironmentalLossContingenciesUndiscountedDueInThirdYear 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. 2020 unf_EstimatedInsuranceProceedsForEnvironmentalLossContingenciesUndiscountedDueInFourthYear 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. 2021 unf_EstimatedInsuranceProceedsForEnvironmentalLossContingenciesUndiscountedDueInFifthYear 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. Thereafter unf_EstimatedInsuranceProceedsForEnvironmentalLossContingenciesUndiscountedDueAfterFifthYear 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. Total unf_EstimatedInsuranceProceedsForEnvironmentalLossContingenciesGross The estimated aggregate undiscounted amount of the estimated insurance proceeds accrual for environmental loss contingencies as of the balance sheet date. Net anticipated costs Accrual for Environmental Loss Contingencies, Net of Estimated Insurance Proceeds, Fiscal Year Maturity [Abstract] Accrual for Environmental Loss Contingencies, Net of Estimated Insurance Proceeds, Fiscal Year Maturity [Abstract] 2017 unf_AccrualForEnvironmentalLossContingenciesUndiscountedRemainderOfFiscalYearNetOfEstimatedInsuranceProceeds 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, within the remainder of the fiscal year. 2018 unf_AccrualForEnvironmentalLossContingenciesUndiscountedDueInTwoYearsNetOfEstimatedInsuranceProceeds 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, in two years of the balance sheet date. 2019 unf_AccrualForEnvironmentalLossContingenciesUndiscountedDueInThreeYearsNetOfEstimatedInsuranceProceeds 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, in three years of the balance sheet date. 2020 unf_AccrualForEnvironmentalLossContingenciesUndiscountedDueInFourYearsNetOfEstimatedInsuranceProceeds 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, in four years of the balance sheet date. 2021 unf_AccrualForEnvironmentalLossContingenciesUndiscountedDueInFiveYearsNetOfEstimatedInsuranceProceeds 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, in five years of the balance sheet date. Thereafter unf_AccrualForEnvironmentalLossContingenciesUndiscountedDueAfterFifthYearNetOfEstimatedInsuranceProceeds 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. Total unf_AccrualForEnvironmentalLossContingenciesNetOfEstimatedInsuranceProceeds Accrual for environmental loss contingencies, net of estimated insurance proceeds, total. Effect of inflation unf_AccrualForEnvironmentalLossContingenciesEffectOfInflation The amount of inflation necessary to increase (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 inflation). Effect of discounting Accrual for Environmental Loss Contingencies, Discount Balance at end of period Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Arrow Uniform Arrow Uniform [Member] Acquired entity, Arrow Uniform. Business Acquisition [Line Items] Business Acquisition [Line Items] Number of business acquisitions completed Number of Businesses Acquired Aggregate purchase price Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Contingent consideration Business Combination, Contingent Consideration, Asset, Current Number of locations unf_NumberOfLocations Represents the number of locations. Number of employees Entity Number of Employees Number of Midwestern states Number of States in which Entity Operates Cash paid upon closing for the acquisition Payments to Acquire Businesses, Gross Receivable due from seller Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables Foreign Currency Translation Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Pension-related Derivative Financial Instruments Total Accumulated Other Comprehensive (Loss) Income AOCI Attributable to Parent [Member] AOCI Attributable to Parent, Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Beginning balance Stockholders' Equity Attributable to Parent Other comprehensive (loss) income before reclassification OCI, before Reclassifications, Net of Tax, Attributable to Parent Amounts reclassified from accumulated other comprehensive (loss) income Ending balance Document And Entity Information Document Information [Table] Document Information [Table] Document Information [Line Items] Document Information [Line Items] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Trading Symbol Trading Symbol Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Receivables Inventories Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory Rental merchandise in service unf_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRentalMerchandiseInService The amount of rental merchandise in service recognized as of the acquisition date. Prepaid expense and other current assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets Property, plant and equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Goodwill Goodwill Intangible assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles Other assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Accrued liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Total Purchase Price Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net Goodwill [Roll Forward] Goodwill [Roll Forward] Beginning balance Goodwill recorded during the period Goodwill, Acquired During Period Other Goodwill, Other Increase (Decrease) Ending balance Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] US and Canadian Rental and Cleaning US and Canadian Rental and Cleaning [Member] Represents U.S. and Canadian rental and cleaning segment. MFG MFG [Member] Represents MFG segment. Corporate Corporate Segment [Member] Subtotal Core Laundry Operations US and Canadian Rental and Cleaning, MFG, and Corporate Segments [Member] US and Canadian Rental and Cleaning, MFG, and Corporate Segments [Member] Specialty Garments Specialty Garments [Member] Represents specialty garments segment. First Aid First Aid [Member] Represents First Aid segment. Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments Operating Segments [Member] Net Interco MFG Elim Intersegment Eliminations [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Income (loss) from operations Interest (income) expense, net Interest Income (Expense), Net Income (loss) before taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring Fair Value, Measurements, Recurring [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Assets: Assets, Fair Value Disclosure [Abstract] Cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Pension plan assets Defined Benefit Plan, Fair Value of Plan Assets Foreign currency forward contracts Foreign Currency Contract, Asset, Fair Value Disclosure Total assets at fair value Assets, Fair Value Disclosure Statement of Financial Position [Abstract] Receivables, reserves Allowance for Doubtful Accounts Receivable, Current Accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Preferred stock, shares outstanding (in shares) Preferred Stock, Shares Outstanding Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (in shares) Common Stock, Shares Authorized Common stock, shares issued (in shares) Common Stock, Shares, Issued Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Schedule of Components of Inventory Schedule of Inventory, Current [Table Text Block] Anti-dilutive securities excluded from calculation of diluted earnings per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Employee Benefit Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Derivative Instruments and Hedging Activities Derivative Instruments and Hedging Activities Disclosure [Text Block] Segment Reporting Segment Reporting Disclosure [Text Block] Assets Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Receivables, less reserves of $11,652 and $7,675 Receivables, Net, Current Inventories Rental merchandise in service Rental merchandise in service Inventories that are actively being utilized by the Company to service its rental customers. This merchandise is amortized over an estimated useful life and is shown net of accumulated amortization. Prepaid taxes Prepaid Taxes Prepaid expenses and other current assets Prepaid Expense, Current Total current assets Assets, Current Property, plant and equipment, net of accumulated depreciation of $689,859 and $661,295 Property, Plant and Equipment, Net Customer contracts, net Customer contracts, net Carrying amount, net of accumulated amortization, as of the balance sheet date of an intangible asset that arises from a contractual arrangement with a third party. Other intangible assets, net Other Intangible Assets, Net Deferred income taxes Deferred Income Tax Assets, Net Other assets Other Assets, Noncurrent Total assets Assets Liabilities and shareholders’ equity Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued liabilities Accrued Liabilities, Current Accrued taxes Accrued Income Taxes, Current Total current liabilities Liabilities, Current Accrued liabilities Accounts Payable and Accrued Liabilities, Noncurrent Accrued and deferred income taxes unf_AccruedAndDeferredIncomeTaxesLongTerm Represents long-term accrued and deferred income taxes. Total liabilities Liabilities Commitments and contingencies (Note 11) Commitments and Contingencies Shareholders’ equity: Stockholders' Equity Attributable to Parent [Abstract] Preferred Stock, $1.00 par value; 2,000,000 shares authorized; no shares issued and outstanding Preferred Stock, Value, Issued Common stock Common Stock, Value, Issued Capital surplus Additional Paid in Capital Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive loss Total shareholders’ equity Total liabilities and shareholders’ equity Liabilities and Equity