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Recurring Basis Fair Value, Assets Measured on Recurring Basis [Table Text Block] Future Minimum Commitments Under Operating Leases Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Segment Reporting [Abstract] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Service Service [Member] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] United States Domestic [Member] Domestic International International [Member] International Revenues from External Customers and Long-Lived Assets [Line Items] Revenues from External Customers and Long-Lived Assets [Line Items] Revenue from services Revenues Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Stock-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Restricted Stock Restricted Stock [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Restricted Stock Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Nonvested, beginning balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Nonvested, ending balance (in shares) Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Nonvested weighted average grant date fair value, beginning balance (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Nonvested weighted average grant date fair value, ending balance (in dollars per share) Other Assets [Abstract] Schedule of Other Assets Schedule of Other Assets, Noncurrent [Table Text Block] Other Income and Expenses [Abstract] Other Expense, Net Other Income and Other Expense Disclosure [Text Block] Revenue from Contract with Customer [Abstract] Revenue Revenue from Contract with Customer [Text Block] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] United States UNITED STATES Canada CANADA Mexico MEXICO Puerto Rico PUERTO RICO Brazil BRAZIL Total Americas Americas [Member] France FRANCE Switzerland SWITZERLAND Portugal PORTUGAL United Kingdom UNITED KINGDOM Russia RUSSIAN FEDERATION Italy ITALY Germany GERMANY Ireland IRELAND Norway NORWAY Other Other EMEA [Member] Other EMEA [Member] Total EMEA EMEA [Member] Total APAC Asia Pacific [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Revenue from services Revenue from Contract with Customer, Excluding Assessed Tax Business Combinations [Abstract] Schedule of Recognized Identified Assets Acquired and Liabilities Assumed Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Summary of Status of Nonvested Restricted Stock Awards and Units Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block] Summary of Status of Nonvested Performance Share Awards Share-based Compensation, Performance Shares Award Nonvested Activity [Table Text Block] Document and Entity Information [Abstract] Document and Entity Information [Abstract] Document Information [Table] Document Information [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Class A common stock Common Class A [Member] Class B common stock Common Class B [Member] Document Information [Line Items] Document Information [Line Items] Entity Registrant Name Entity Registrant Name Document Type Document Type Current Fiscal Year End Date Current Fiscal Year End Date Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Public Float Entity Public Float Amendment Flag Amendment Flag Entity Central Index Key Entity Central Index Key Entity Current Reporting Status Entity Current Reporting Status Entity Voluntary Filers Entity Voluntary Filers Entity Filer Category Entity Filer Category Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Entity Emerging Growth Company Entity Emerging Growth Company Entity Small Business Entity Small Business Entity Shell Company Entity Shell Company Stockholders' Equity Note [Abstract] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2016-01 Accounting Standards Update 2016-01 [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Foreign Currency Translation Adjustments Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Unrealized Gains and Losses on Investment Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] Pension Liability Adjustments Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Balance at beginning of year Stockholders' Equity Attributable to Parent Cumulative-effect adjustment from adoption of ASU 2016-01, Financial Instruments Cumulative Effect of New Accounting Principle in Period of Adoption Other comprehensive income (loss) before classifications OCI, before Reclassifications, Net of Tax, Attributable to Parent Amounts reclassified from accumulated other comprehensive income Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent Net current-period other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Balance at end of year Supplemental Cash Flow Elements [Abstract] Increase in trade accounts receivable Increase (Decrease) in Accounts Receivable Increase in prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Increase in accounts payable and accrued liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities (Decrease) increase in accrued payroll and related taxes Increase (Decrease) in Employee Related Liabilities Increase in accrued workers’ compensation and other claims Increase (Decrease) in Workers' Compensation Liabilities Increase in income and other taxes Increase (Decrease) in Accrued Taxes Payable Total changes in operating assets and liabilities, net of acquisition Increase (Decrease) in Operating Capital Income Tax Disclosure [Abstract] Income tax based on statutory rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount State income taxes, net of federal benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Foreign tax rate differential Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount General business credits Effective Income Tax Rate Reconciliation, Tax Credit, Amount Life insurance cash surrender value Life insurance cash surrender value The portion of the difference between total income tax expense or benefit as reported in the Income Statement and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates attributable to gains and losses on company owned life insurance contracts. Foreign items Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Amount GILTI, net of foreign tax credit Effective Income Tax Rate Reconciliation, Global Intangible Low-Taxed Income, Net of Foreign Tax Credit, Amount Effective Income Tax Rate Reconciliation, Global Intangible Low-Taxed Income, Net of Foreign Tax Credit, Amount Foreign-derived intangible income Effective Income Tax Rate Reconciliation, Deduction, Extraterritorial Income Exclusion, Amount Foreign business taxes Foreign business taxes The portion of the difference between total income tax expense or benefit as reported in the Income Statement and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates attributable to foreign business taxes classified as income taxes which are based on revenue or receipts reduced by one or more category of expense. Non-deductible expenses Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount Tax law change Tax Law Change The portion of the difference between total income tax expense or benefit as reported in the Income Statement and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations, that is attributable to changes in the enacted income tax laws in the period. PersolKelly Asia Pacific transaction gain Effective Income Tax Rate Reconciliation, Disposition of Business, Amount Change in deferred tax realizability Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount Stock compensation Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount Other, net Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Total provision Income Tax Expense (Benefit) Earnings Per Share [Abstract] Net earnings Net Income (Loss) Attributable to Parent Less: Earnings allocated to participating securities Participating Securities, Distributed and Undistributed Earnings (Loss), Basic and Diluted Amount of earnings (loss) distributed and earnings (loss) allocated to participating securities for the basic and diluted earnings (loss) per share or per unit calculation under the two-class method. Net earnings available to common shareholders Net Earnings Available To Common Shareholders Net earnings after earnings distributed and allocated to participating securities under the two-class method. Average common shares outstanding (millions): Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract] Basic (in shares) Weighted Average Number of Shares Outstanding, Basic Dilutive share awards (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Basic earnings (loss) per share on common stock (in dollars per share) Earnings Per Share, Basic Diluted earnings (loss) per share on common stock (in dollars per share) Earnings Per Share, Diluted Statement of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net earnings Adjustments to reconcile net earnings to net cash from operating activities: Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Provision for bad debts Provision for Doubtful Accounts Stock-based compensation Share-based Compensation Deferred income taxes Deferred Income Tax Expense (Benefit) Loss on investment in Persol Holdings Gain (Loss) on Investments, Excluding Other than Temporary Impairments Gain on investment in PersolKelly Asia Pacific Gain (Loss) on Disposition of Business Equity in net earnings of PersolKelly Asia Pacific Income (Loss) from Equity Method Investments Other, net Other Noncash Income (Expense) Changes in operating assets and liabilities, net of acquisition Net cash from operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Capital expenditures Payments to Acquire Productive Assets Acquisition of company, net of cash received Payments to Acquire Businesses, Net of Cash Acquired Investment in equity securities Payments to Acquire Investments Net cash proceeds from investment in PersolKelly Asia Pacific equity affiliate Proceeds from Divestiture of Businesses, Net of Cash Divested (Loan to) proceeds from repayment of loan to equity affiliate Proceeds from (Repayments of) Related Party Debt Proceeds from company-owned life insurance Proceeds from Life Insurance Policy Other investing activities Payments for (Proceeds from) Other Investing Activities Net cash (used in) from investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Net change in short-term borrowings Proceeds from (Repayments of) Short-term Debt Dividend payments Payments of Ordinary Dividends, Common Stock Payments of tax withholding for restricted shares Payments Related to Tax Withholding for Share-based Compensation Other financing activities Proceeds from (Payments for) Other Financing Activities Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Effect of exchange rates on cash, cash equivalents and restricted cash Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Net change in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash, cash equivalents and restricted cash at beginning of year Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, cash equivalents and restricted cash at end of year Cash and equivalents Cash and Cash Equivalents, at Carrying Value Restricted cash included in prepaid expenses and other current assets Restricted Cash, Current Restricted cash included in other assets Restricted Cash, Noncurrent Interest paid Interest Paid, Including Capitalized Interest, Operating and Investing Activities Income taxes paid Income Taxes Paid, Net Non-cash capital expenditures Capital Expenditures Incurred but Not yet Paid Statement of Financial Position [Abstract] Statement [Table] Statement [Table] Statement [Line Items] Statement [Line Items] Allowance for trade accounts receivable Allowance for Doubtful Accounts Receivable, Current Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares issued (in shares) Common Stock, Shares, Issued Treasury stock, Class A shares (in shares) Treasury Stock, Shares Income Taxes [Table] Income Taxes [Table] Income Taxes [Table] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Persol Holdings Investment Persol Holdings Investment [Member] Persol Holdings Investment [Member] PersolKelly Asia Pacific PersolKelly Asia Pacific [Member] PersolKelly Asia Pacific Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Pro Forma Pro Forma [Member] Tax Credit Carryforward [Axis] Tax Credit Carryforward [Axis] Tax Credit Carryforward, Name [Domain] Tax Credit Carryforward, Name [Domain] General Business Tax Credit Carryforward General Business Tax Credit Carryforward [Member] Foreign Tax Credit Carryforward Foreign Tax Credit Carryforward [Member] Foreign Tax Credit Carryforward [Member] State Credit Carryforward State Credit Carryforward [Member] State Credit Carryforward [Member] Income Taxes [Line Items] Income Taxes [Line Items] [Line Items] for Income Taxes [Table] U.S. statutory rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Income tax benefit Deferred tax asset revaluation, income tax expense Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Deferred Tax Asset Revaluation, Provisional Income Tax Expense Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Deferred Tax Asset Revaluation, Provisional Income Tax Expense Tax expense on gain on investment in PersolKelly Asia Pacific equity affiliate Tax Effect of Gain from Disposal of Business Amount of tax expense on gain not previously recognized resulting from the disposal of a business that does not qualify as a discontinued operation. Transition tax Transition Tax Provisional amount recorded related to the U.S. tax law change imposing a one-time transition tax on accumulated foreign earnings. General business credit carryforward Tax Credit Carryforward, Amount Loss carryforwards Deferred Tax Assets, Operating Loss Carryforwards Valuation allowance Deferred Tax Assets, Valuation Allowance Undistributed earnings of foreign subsidiaries Undistributed Earnings of Foreign Subsidiaries Potential repatriation of foreign earnings amount Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount Unrecognized tax benefits Unrecognized Tax Benefits Unrecognized tax benefits that would impact effective tax rate Unrecognized Tax Benefits that Would Impact Effective Tax Rate Unrecognized tax benefits, income tax penalties and interest accrued Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued Significant change in unrecognized tax benefits is reasonably possible, amount of unrecorded benefit Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit Accounting Policies [Abstract] Summary of Significant Accounting Policies Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block] Equity Method Investments and Joint Ventures [Abstract] Investment in PersolKelly Asia Pacific Equity Method Investments and Joint Ventures Disclosure [Text Block] Earnings (Loss) From Continuing Operations Before Taxes Per Jurisdiction Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block] Provision for Income Taxes From Continuing Operations Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Deferred Taxes Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Differences Between Income Taxes From Continuing Operations and U.S. Statutory Rate Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Net Tax Effect of State and Foreign Loss Carryforwards Summary of Operating Loss Carryforwards [Table Text Block] Reconciliation of Unrecognized Tax Benefits Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block] Changes In Operating Assets And Liabilities, Net of the Effect of Deconsolidated Subsidiaries Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Schedule of Quarterly Financial Information Quarterly Financial Information [Table Text Block] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Intersegment Eliminations Intersegment Eliminations [Member] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Americas Staffing Americas Staffing [Member] Staffing segment activity in the regions of North America and South America. International Staffing International Staffing [Member] Staffing segment activity in the regions of Europe, Middle East and Africa and Asia Pacific. Talent Fulfillment Talent Fulfillment [Member] Talent Fulfillment [Member] Subsegments [Axis] Subsegments [Axis] Subsegments [Domain] Subsegments [Domain] Commercial Commercial [Member] Commercial [Member] Educational Staffing Educational Staffing [Member] Educational Staffing [Member] PT PT [Member] PT [Member] Permanent Placement Permanent Placement [Member] Permanent Placement [Member] Staffing Solutions Staffing Solutions [Member] Staffing Solutions [Member] Talent Solutions Talent Solutions [Member] Talent Solutions [Member] Outcome-Based Services Outcome-Based Services [Member] Outcome-Based Services [Member] Global Talent Solutions Global Talent Solutions [Member] Global Talent Solutions [Member] Retirement Benefits [Abstract] Liability for nonqualified plans Deferred Compensation Liability, Current and Noncurrent Earnings (loss) included in SG&A expenses Earnings on Unqualified Deferred Compensation Plan Liability The cost participants' earnings (losses) on the unqualified deferred compensation plan liability. Life insurance cash surrender value Deferred Compensation Plan Assets Tax-free earnings (loss) included in SG&A expenses Earnings Losses on Value of Deferred Compensation Assets Earnings (losses) on the value of the deferred compensation assets. Net expense for retirement benefits Defined Contribution Plan, Cost Benefit obligation Defined Benefit Plan, Benefit Obligation Fair value of plan assets Defined Benefit Plan, Plan Assets, Amount Unfunded liability Defined Benefit Plan, Funded (Unfunded) Status of Plan Pension expense Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Finite-lived intangible asset, useful life Finite-Lived Intangible Asset, Useful Life Loss Contingencies [Table] Loss Contingencies [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Prepaid Expenses and Other Current Assets Prepaid Expenses and Other Current Assets [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Accrual for litigation costs Loss Contingency Accrual Insurance recoveries Estimated Insurance Recoveries Loss contingency, portion not accrued Loss Contingency, Range of Possible Loss, Portion Not Accrued Changes in Accumulated Other Comprehensive Income by Component, Net of Tax Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Interest income Investment Income, Interest Interest expense Interest Expense Dividend income Investment Income, Dividend Foreign exchange gains (losses) Foreign Currency Transaction Gain (Loss), before Tax Other Other Nonoperating Expense Other expense, net Other Nonoperating Income (Expense) Schedule of Goodwill [Table] Schedule of Goodwill [Table] GTS GTS [Member] Global Talent Solutions segment activity in the Americas, EMEA and APAC. Goodwill [Line Items] Goodwill [Line Items] Goodwill [Roll Forward] Goodwill [Roll Forward] Goodwill, beginning balance Goodwill Additions to Goodwill Goodwill, Purchase Accounting Adjustments Goodwill, ending balance Related Party Transactions [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Title of Individual [Axis] Title of Individual [Axis] Relationship to Entity [Domain] Relationship to Entity [Domain] Executive Chairman and Chairman of the Board and Director Executive Chairman and Chairman of the Board and Director [Member] Executive Chairman and Chairman of the Board and Director Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Terence E. Adderley Terence E. Adderley [Member] Terence E. Adderley Terence E. Adderley Revocable Trust K [Member] Terence E. Adderley Revocable Trust K [Member] Terence E. Adderley Revocable Trust K [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Ownership percentage of parent company Ownership Percentage of Parent Company Ownership Percentage of Parent Company Domestic Income (Loss) from Continuing Operations before Income Taxes, Domestic Foreign Income (Loss) from Continuing Operations before Income Taxes, Foreign Earnings (loss) before taxes and equity in net earnings (loss) of affiliate Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Investment in Persol Holdings [Abstract] Investment in Persol Holdings [Abstract] Schedule of Gain (Loss) on Securities [Table] Schedule of Gain (Loss) on Securities [Table] OCI & AOCI OCI & AOCI [Member] OCI & AOCI [Member] Investment [Axis] Investment [Axis] Investment [Domain] Investment [Domain] Persol Holdings Investment Temp Holdings Investment [Member] Temp Holdings Investment [Member] Gain (Loss) on Securities [Line Items] Gain (Loss) on Securities [Line Items] Loss on investment in Persol Holdings Unrealized gain (loss) on available-for-sale investment, net of tax Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax Cumulative effect of new accounting principle in period of adoption Cumulative effect of new accounting principle in period of adoption, taxes Cumulative Effect of New Accounting Principle in Period of Adoption, Taxes Cumulative Effect of New Accounting Principle in Period of Adoption, Taxes New Accounting Pronouncements Description of New Accounting Pronouncements Not yet Adopted [Text Block] Debt Disclosure [Abstract] Debt Debt Disclosure [Text Block] Contingencies Legal Matters and Contingencies [Text Block] Earnings Per Share Earnings Per Share [Text Block] Related Party Transactions Related Party Transactions Disclosure [Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Segment Disclosures Segment Reporting Disclosure [Text Block] Statement of Stockholders' Equity [Abstract] Accounting Standards Update 2014-09 Accounting Standards Update 2014-09 [Member] Common Stock Common Stock [Member] Treasury Stock Treasury Stock [Member] Paid-in Capital Additional Paid-in Capital [Member] Earnings Invested in the Business Earnings Invested In The Business [Member] Earnings Invested In The Business [Member] Class A common stock, Capital Stock Class B common stock, Capital Stock Class A common stock, Treasury Stock Common Class A Treasury Stock [Member] Common Class A Treasury Stock [Member] Class B common stock, Treasury Stock Common Class B Treasury Stock [Member] Common Class B Treasury Stock [Member] Increase (Decrease) in Stockholders' Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Issuance of restricted stock and other Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Dividends Dividends, Common Stock, Cash Other comprehensive income (loss), net of tax Other Comprehensive Income (Loss), Net of Tax Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Teachers On Call, Inc. Teachers On Call, Inc. [Member] Teachers On Call, Inc. [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Ownership percentage acquired Business Acquisition, Percentage of Voting Interests Acquired Purchase price of acquisition Business Combination, Consideration Transferred Purchase price paid at closing Payments to Acquire Businesses, Gross Goodwill expected to be deductible Business Acquisition, Goodwill, Expected Tax Deductible Amount Indemnification asset recognized as of the acquisition date Business Combination, Indemnification Assets, Amount as of Acquisition Date Indemnification asset Business Combination, Indemnification Assets, Amount Business Combination, Indemnification Assets, Amount French CICE Wage subsidy receivable Wage subsidy receivable is related to a law to enhance the competitiveness of businesses in France. Intangibles, net of accumulated amortization Intangible Assets, Net (Excluding Goodwill) Long-term customer receivable Accounts Receivable, Net, Noncurrent Workers' compensation receivable Other Other Assets, Miscellaneous, Noncurrent Other assets Other Assets, Noncurrent Intangibles, accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Fiscal period duration Fiscal Period Duration Advertising expense Advertising Expense Schedule of Short-term Debt [Table] Schedule of Short-term Debt [Table] Short-term Debt, Type [Axis] Short-term Debt, Type [Axis] Short-term Debt, Type [Domain] Short-term Debt, Type [Domain] Book overdrafts Book Overdrafts [Member] Represents outstanding checks in excess of funds on deposit that are reclassified to a liability. Short-term Debt [Line Items] Short-term Debt [Line Items] Equity method investment, ownership percentage Equity Method Investment, Ownership Percentage Accounts payable Accounts Payable and Accrued Liabilities, Current Accrued payroll and related taxes Employee-related Liabilities, Current Liability for claims Liability for Claims and Claims Adjustment Expense Lease expense Operating Leases, Rent Expense, Net Noncancelable purchase obligations Unrecorded Unconditional Purchase Obligation Unrecorded unconditional purchase obligation term Obligation Expected Utilization Period Obligation Expected Utilization Period Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Business Talent Group, LLC Business Talent Group, LLC [Member] Business Talent Group, LLC [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] Cost of equity securities Equity Securities, FV-NI, Cost Equity securities without readily determinable fair value, amount Equity Securities without Readily Determinable Fair Value, Amount Other Assets Other Assets Disclosure [Text Block] Subsequent Event [Table] Subsequent Event [Table] Global Technology Associates, LLC Global Technology Associates, LLC [Member] Global Technology Associates, LLC [Member] NextGen Global Resources LLC NextGen Global Resources LLC [Member] NextGen Global Resources LLC [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Acquisition related costs Business Combination, Acquisition Related Costs Acquisition Business Combination Disclosure [Text Block] Components of Deferred Tax Assets and Liabilities Components of Deferred Tax Assets and Liabilities [Abstract] Depreciation and amortization Deferred Tax Liabilities, Property, Plant and Equipment Employee compensation and benefit plans Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits Workers’ compensation Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Self Insurance Unrealized gain on securities Deferred Tax Liabilities, Investments Investment in equity affiliate Deferred Tax Assets, Equity Method Investments Loss carryforwards Credit carryforwards Deferred Tax Assets, Tax Credit Carryforwards Other, net Deferred Tax Assets, Other Valuation allowance Deferred Tax Assets, Net Deferred Tax Assets, Net Property and Equipment at Cost and Depreciable Useful Lives Property, Plant and Equipment [Table Text Block] Fiscal Year Fiscal Period, Policy [Policy Text Block] Principles of Consolidation Consolidation, Policy [Policy Text Block] Investment in Persol Holdings Marketable Securities, Policy [Policy Text Block] Investment in PersolKelly Asia Pacific Equity Method Investments [Policy Text Block] Foreign Currency Translation Foreign Currency Transactions and Translations Policy [Policy Text Block] Cost of Services Cost of Sales, Policy [Policy Text Block] Advertising Expenses Advertising Cost, Policy, Expensed Advertising Cost [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Cash and Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Property and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Operating Leases Lessee, Leases [Policy Text Block] Goodwill and Other Intangible Assets Goodwill and Intangible Assets, Policy [Policy Text Block] Impairment of Long-Lived Assets, Intangible Assets, Equity Method Investments and Equity Securities Impairment or Disposal of Long-Lived Assets, Including Intangible Assets, Policy [Policy Text Block] Accounts Payable Accounts Payable [Policy Text Block] Accounts Payable [Policy Text Block] Accrued Payroll and Related Taxes Accrued Payroll and Related Taxes [Policy Text Block] Accrued Payroll and Related Taxes [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Stock-Based Compensation Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Earnings Per Share Earnings Per Share, Policy [Policy Text Block] Workers' Compensation Workers Compensation Policy [Policy Text Block] Disclosure of accounting policy for establishing accruals for workers' compensation claims. Segment Disclosures Segment Reporting, Policy [Policy Text Block] New Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Revenue Recognition Revenue Recognition, Policy [Policy Text Block] Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] TS Kelly Workforce Solutions TS Kelly Workforce Solutions [Member] TS Kelly Workforce Solutions [Member] Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Proceeds from investment in PersolKelly Asia Pacific equity affiliate Proceeds from Divestiture of Businesses Investment in equity affiliate Equity Method Investments Deconsolidated goodwill Disposal Group, Including Discontinued Operation, Goodwill Post-close cash true-up adjustment Disposal Group, Including Discontinued Operation, Consideration Equity in net earnings (loss) of affiliate Gain on investment in PersolKelly Asia Pacific Due from PersolKelly Asia Pacific Due from Affiliates Advances to PersolKelly Asia Pacific Advances to Affiliate Due to PersolKelly Asia Pacific Due to Affiliate Repayment of loan Repayment of Notes Receivable from Related Parties SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table] SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] Allowance for doubtful accounts SEC Schedule, 12-09, Allowance, Credit Loss [Member] Deferred tax assets valuation allowance SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] Balance at beginning of year SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount Charged to costs and expenses SEC Schedule, 12-09, Valuation Allowances and Reserves, Additions, Charge to Cost and Expense Charged to other accounts SEC Schedule, 12-09, Valuation Allowances and Reserves, Additions, Charge to Other Account Currency exchange effects SEC Schedule, 12-09, Valuation Allowances and Reserves, Increase (Decrease) Adjustment Deductions from reserves SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction Balance at end of year Deferred tax asset Deferred Tax Assets, Net, Noncurrent Other long-term liabilities Deferred Tax Liabilities, Net, Noncurrent Deferred tax assets, net Indefinite-lived Intangible Assets [Axis] Indefinite-lived Intangible Assets [Axis] Indefinite-lived Intangible Assets, Major Class Name [Domain] Indefinite-lived Intangible Assets, Major Class Name [Domain] Trademarks Trademarks [Member] 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 Relationships Customer Relationships [Member] Candidate Database Database Rights [Member] Intangibles Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Intangible amortization expense Amortization of Intangible Assets Advances to PersolKelly Asia Pacific Deferred sales commission Deferred Sales Commission Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Finite-lived intangible assets, amortization expense, next 12 months Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months Finite-lived intangible assets, amortization expense, year 2 Finite-Lived Intangible Assets, Amortization Expense, Year Two Finite-lived intangible assets, amortization expense, year 3 Finite-Lived Intangible Assets, Amortization Expense, Year Three Finite-lived intangible assets, amortization expense, year 4 Finite-Lived Intangible Assets, Amortization Expense, Year Four Finite-lived intangible assets, amortization expense, year 5 Finite-Lived Intangible Assets, Amortization Expense, Year Five Gross profit Gross Profit SG&A expenses Selling, General and Administrative Expense Restructuring charges included in SG&A expenses Restructuring Charges Gain (loss) on investment in Persol Holdings Net earnings (loss) Dividends per share (in dollars per share) Common Stock, Dividends, Per Share, Cash Paid Quantifying misstatement in current year financial statements amount Quantifying Misstatement in Current Year Financial Statements, Amount Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Class of Stock [Line Items] Class of Stock [Line Items] Common stock, shares authorized (in shares) Common Stock, Shares Authorized Income Taxes Income Tax Disclosure [Text Block] Income Statement [Abstract] Cost of services Cost of Goods and Services Sold Gross profit Selling, general and administrative expenses Earnings from operations Operating Income (Loss) Other expense, net Income tax (benefit) expense Net earnings before equity in net earnings (loss) of affiliate Income (Loss) from Continuing Operations Before Equity Method Investments Amount of income (loss) from continuing operations before addition of income (loss) from equity method investments. Net earnings Basic earnings per share Diluted earnings per share Dividends per share Average shares outstanding (millions): Weighted Average Number of Shares Outstanding, Diluted [Abstract] Diluted (in shares) Award Date [Axis] Award Date [Axis] Award Date [Domain] Award Date [Domain] 2018 grant 2018 grant [Member] 2018 grant [Member] 2017 grant 2017 grant [Member] 2017 grant [Member] 2016 grant 2016 grant [Member] 2016 grant [Member] Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] Performance shares eligible to earn more than target Performance shares eligible to earn more than target [Member] Performance shares eligible to earn more than target, up to maximum [Member] Maximum shares eligible to earn Maximum shares eligible to earn [Member] Maximum shares eligible to earn for award. Nature of Expense [Axis] Nature of Expense [Axis] Interim Period, Costs Not Allocable [Domain] Interim Period, Costs Not Allocable [Domain] Stock-based compensation cost Stock Based Compensation Cost [Member] Performance Shares Performance Shares [Member] Performance Shares, Financial Goals Performance Shares, Financial Goals [Member] Performance Shares, Financial Goals [Member] Performance Shares, Total Shareholder Return Performance Shares, Total Shareholder Return [Member] Performance Shares, Total Shareholder Return [Member] Performance Shares, Single Financial Goal Performance Shares, Single Financial Goal [Member] Performance Shares, Single Financial Goals Valuation Approach and Technique [Axis] Valuation Approach and Technique [Axis] Valuation Approach and Technique [Domain] Valuation Approach and Technique [Domain] Monte Carlo Fair Value Monte Carlo Fair Value [Member] A simulation model incorporating assumptions for inputs of expected stock price volatility, dividend yield and risk-free interest rate, which are used to calculate the fair value at the grant date for performance shares with market conditions. Maximum number of shares available for grants - Evergreen provision Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Outstanding Stock Maximum Plan activity adjustment period - Evergreen provision PlanActivityAdjustmentPeriod Period over which plan activity is adjusted to determine the maximum number of shares that may be issued in accordance with the plan. Maximum number of shares available for grants - Fixed provision Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized Number of shares available for grant (in shares) - Fixed provision Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Stock-based compensation cost Allocated Share-based Compensation Expense Tax benefit Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Award vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Unrecognized compensation cost, unvested restricted stock Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options Compensation cost not yet recognized, period for recognition Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Grants in period (in dollars per share) Vested in period, fair value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Maximum target percentage allowed under grant Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage Performance measurement period Share-based Compensation Arrangement by Share-based Payment Award, Performance Measurement Period Share-based Compensation Arrangement by Share-based Payment Award, Performance Measurement Period Weighted average grant date fair value (in dollars per share) Total nonvested shares (in shares) Actual percentage achieved Actual Percentage Achieved Actual percentage achieved. Statement of Comprehensive Income [Abstract] Other comprehensive income, net of tax: Other Comprehensive Income (Loss), Net of Tax [Abstract] Foreign currency translation adjustments, net of tax benefit of $0.4 million, tax expense of $0.2 million and tax expense of $0.0 million, respectively Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Less: Reclassification adjustments included in net earnings Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Unrealized gains (losses) on investment, net of tax expense of $0.0 million, tax expense of $30.2 million and tax benefit of $0.7 million, respectively Pension liability adjustments, net of tax expense of $0.2 million, tax benefit of $0.1 million and tax benefit of $0.0 million, respectively Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax Less: Reclassification adjustments included in net earnings Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax Pension liability adjustments Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Other comprehensive income (loss) Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] The Facility The Facility [Member] The Facility Securitization Facility Securitization Facility [Member] Unsecured Uncommitted Short-term Local Credit Facilities Unsecured Uncommitted Short Term Local Credit Facilities [Member] Unsecured Uncommitted Short Term Local Credit Facilities Revolving Line of Credit Line of Credit [Member] Facility Fee Facility Fee [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Standby Letter of Credit Related to Workers' Compensation Standby Letter Of Credit Related To Workers Compensation [Member] Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Short-term borrowings Short-term Debt Interest rate Line of Credit Facility, Interest Rate at Period End Remaining borrowing capacity Line of Credit Facility, Remaining Borrowing Capacity Commitment fee percentage (in basis points) Line of Credit Facility, Commitment Fee Percentage Securitization facility term Debt Instrument, Term Letters of credit outstanding Letters of Credit Outstanding, Amount Assets Assets [Abstract] Current Assets Assets, Current [Abstract] Trade accounts receivable, less allowances of $13.2 million and $12.9 million, respectively Accounts Receivable, Net, Current Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Total current assets Assets, Current Noncurrent Assets Assets, Noncurrent [Abstract] Property and equipment: Property, Plant and Equipment [Abstract] Property and equipment Property, Plant and Equipment, Gross Accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Net property and equipment Property, Plant and Equipment, Net Deferred taxes Goodwill, net Investment in Persol Holdings Equity Securities, FV-NI Other assets Total noncurrent assets Assets, Noncurrent Total Assets Assets Liabilities and Stockholders' Equity Liabilities and Equity [Abstract] Current Liabilities Liabilities, Current [Abstract] Accounts payable and accrued liabilities Accrued workers' compensation and other claims Workers' Compensation Liability, Current Income and other taxes Taxes Payable, Current Total current liabilities Liabilities, Current Noncurrent Liabilities Liabilities, Noncurrent [Abstract] Accrued workers' compensation and other claims Workers' Compensation Liability, Noncurrent Accrued retirement benefits Deferred Compensation Liability, Classified, Noncurrent Other long-term liabilities Other Liabilities, Noncurrent Total noncurrent liabilities Liabilities, Noncurrent Commitments and contingencies (See Commitments and Contingencies footnotes) Commitments and Contingencies Stockholders' Equity Stockholders' Equity Attributable to Parent [Abstract] Capital stock, $1.00 par value Capital stock, $1.00 par value [Abstract] Capital stock, $1.00 par value [Abstract] Common stock, value Common Stock, Value, Issued Treasury stock, at cost Treasury stock, at cost [Abstract] Treasury stock, at cost [Abstract] Treasury stock, value Treasury Stock, Value Paid-in capital Additional Paid in Capital Earnings invested in the business Retained Earnings (Accumulated Deficit) Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Total stockholders' equity Total Liabilities and Stockholders' Equity Liabilities and Equity Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Measured on a recurring basis Fair Value, Measurements, Recurring [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [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] Money market funds Money Market Funds, at Carrying Value Total assets at fair value Assets, Fair Value Disclosure Cash Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Other current assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other Goodwill Other noncurrent assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Current liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities Purchase price paid at closing Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Goodwill Goodwill Disclosure [Text Block] Supplemental Cash Flow Information Cash Flow, Supplemental Disclosures [Text Block] Performance Shares, Financial Measure Performance Shares, Financial Measure [Member] Performance Shares, Financial Measure [Member] Performance Shares Vested (in shares) Forfeited (in shares) Weighted Average Grant Date Fair Value Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Balance at beginning of the year Additions for prior years’ tax positions Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Reductions for prior years’ tax positions Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Additions for settlements Unrecognized Tax Benefits, Increase Resulting from Settlements with Taxing Authorities Reductions for settlements Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities Reductions for expiration of statutes Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Balance at end of the year Reconciliation of Revenue from Segments to Consolidated [Table] Reconciliation of Revenue from Segments to Consolidated [Table] Reporting Segments Operating Segments [Member] Less: Intersegment revenue Segment Reporting, Revenue Reconciling Item [Line Items] Segment Reporting, Revenue Reconciling Item [Line Items] Revenue from Services: Revenues [Abstract] Foreign currency translation adjustments, tax expense (benefit) Other Comprehensive Income (Loss), Foreign Currency Translation Gain (Loss) Arising During Period, Tax Tax expense (benefit) on unrealized gains (losses) Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, Tax Pension liability adjustments, tax expense (benefit) Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax Fair Value Measurements Fair Value Disclosures [Text Block] Retirement Benefits Pension and Other Postretirement Benefits Disclosure [Text Block] Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Common Stock Reconciliation of Basic and Diluted Earnings Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Number of reportable segments Number of Reportable Segments Long-lived assets Schedule II - Valuation Reserves SEC Schedule, 12-09, Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] New Accounting Pronouncements [Abstract] New Accounting Pronouncements [Abstract] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Accounting Standards Update 2016-02 Accounting Standards Update 2016-02 [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Operating lease, right-of-use asset Operating Lease, Right-of-Use Asset Operating lease, liability Operating Lease, Liability Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Investment in Persol Holdings Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Segment Revenue from Services Reconciliation of Revenue from Segments to Consolidated [Table Text Block] Segment Earnings from Operations Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block] Summary of Revenue From Services by Geographic Area Revenue from External Customers by Geographic Areas [Table Text Block] Summary of Long-Lived Assets By Geographic Area Long-lived Assets by Geographic Areas [Table Text Block] Schedule of Other Expense, Net Schedule of Other Nonoperating Income (Expense) [Table Text Block] Current tax expense: Current Income Tax Expense (Benefit), Continuing Operations [Abstract] U.S. federal Current Federal Tax Expense (Benefit) U.S. state and local Current State and Local Tax Expense (Benefit) Foreign Current Foreign Tax Expense (Benefit) Total current Current Income Tax Expense (Benefit) Deferred tax (benefit) expense: Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] U.S. federal Deferred Federal Income Tax Expense (Benefit) U.S. state and local Deferred State and Local Income Tax Expense (Benefit) Foreign Deferred Foreign Income Tax Expense (Benefit) Total deferred Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Tax Period [Axis] Tax Period [Axis] Tax Period [Domain] Tax Period [Domain] 2019-2020 Expiring in Years 2019 to 2020 [Member] Expiring in Years 2019 to 2020 [Member] 2021-2035 Expiring in Years 2021 to 2035 [Member] Expiring in Years 2021 to 2035 [Member] Operating Loss Carryforwards [Line Items] Operating Loss Carryforwards [Line Items] Subject to expiration Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration No expiration Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration Total Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Land Land [Member] Work in process Workinprocess [Member] Buildings and improvements Building and Building Improvements [Member] Computer hardware and software Computerhardwareandsoftware [Member] Equipment, furniture and fixtures Equipmentfurnitureandfixtures [Member] Leasehold improvements Leasehold Improvements [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Estimated useful life Property, Plant and Equipment, Useful Life Depreciation expense Depreciation Revenue, Initial Application Period Cumulative Effect Transition [Table] Revenue, Initial Application Period Cumulative Effect Transition [Table] Capitalized Contract Cost [Axis] Capitalized Contract Cost [Axis] Capitalized Contract Cost [Domain] Capitalized Contract Cost [Domain] Deferred Sales Commissions Deferred Sales Commissions [Member] Deferred Sales Commissions [Member] Deferred Fulfillment Costs Deferred Fulfillment Costs [Member] Deferred Fulfillment Costs [Member] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Domain] Timing of Transfer of Good or Service [Domain] Transferred at Point in Time Transferred at Point in Time [Member] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Domain] Initial Application Period Cumulative Effect Transition [Domain] Difference between Revenue Guidance in Effect before and after Topic 606 Difference between Revenue Guidance in Effect before and after Topic 606 [Member] Revenue, Initial Application Period Cumulative Effect Transition [Line Items] Revenue, Initial Application Period Cumulative Effect Transition [Line Items] Contract with customer, asset Contract with Customer, Asset, Gross Deferred revenue Deferred Revenue Deferred tax liabilities Deferred Tax Liabilities, Net Revenue, payment terms Revenue, Payment Terms Revenue, Payment Terms Capitalized contract cost, gross Capitalized Contract Cost, Gross Capitalized contract cost, amortization Capitalized Contract Cost, Amortization Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table] Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table] Corporate Corporate, Non-Segment [Member] Earnings from Operations: Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] SG&A expenses Other expense, net