Debt Disclosure [Abstract] Line of Credit Facility [Table] Line of Credit Facility [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] 1.25% convertible senior notes due 2019 Convertible Debt [Member] Convertible Senior Notes [Line Items] Convertible Senior Notes [Line Items] Convertible Senior Notes [Line Items] Proceeds Debt Instrument, Face Amount Less: debt discount, net of amortization Debt Instrument, Unamortized Discount Debt Issuance Costs, Net Debt Issuance Costs, Net Net carrying amount Long-term Debt Equity component Debt Instrument, Convertible, Carrying Amount of Equity Component Fair Value Disclosures [Abstract] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Convertible debt investment Convertible Debt Securities [Member] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Shorelight Holdings LLC Shorelight Holdings Llc [Member] Shorelight Holdings 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] Fair Value of Financial Instruments [Abstract] Financial Instruments, Owned, at Fair Value [Abstract] Investments in notes Long-term Investments Debt Instrument, Maturity Date Debt Instrument, Maturity Date Aggregate principal amount Closing price of common stock Share Price Accounting Policies [Abstract] Basis of Presentation Basis of Accounting [Text Block] Revenue from Contract with Customer [Abstract] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Performance Obligation Satisfied in Prior Period [Axis] Performance Obligation Satisfied in Prior Period [Axis] Performance Obligation Satisfied in Prior Period [Axis] Performance Obligation Satisfied in Prior Period [Domain] Performance Obligation Satisfied in Prior Period [Domain] [Domain] for Performance Obligation Satisfied in Prior Period [Axis] Release of Allowance [Member] Release of Allowance [Member] Release of Allowance [Member] Change in Estimated Variable Consideration [Member] Change in Estimated Variable Consideration [Member] Change in Estimated Variable Consideration [Member] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Contract with Customer, Performance Obligation Satisfied in Previous Period Contract with Customer, Performance Obligation Satisfied in Previous Period Revenue, Remaining Performance Obligation, Amount Revenue, Remaining Performance Obligation, Amount Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Underlying Asset Class [Axis] Underlying Asset Class [Axis] Underlying Asset Class [Domain] Underlying Asset Class [Domain] Deferred Compensation Plan Assets [Member] Deferred Compensation Plan Assets [Member] Deferred Compensation Plan Assets [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Measurement Frequency [Domain] Measurement Frequency [Domain] Fair Value, Measurements, Recurring Fair Value, 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 2 Fair Value, Inputs, Level 2 [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Interest Rate Swap [Member] Interest Rate Swap [Member] Liability Class [Axis] Liability Class [Axis] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Contingent consideration for business acquisitions Contingent Consideration Liability [Member] Contingent Consideration Liability [Member] Liabilities: Liabilities, Fair Value Disclosure [Abstract] Fair Value, Asset/Liability Assets, Fair Value Disclosure [Abstract] Assets, fair value Assets, Fair Value Disclosure Financial and Nonfinancial Liabilities, Fair Value Disclosure Financial and Nonfinancial Liabilities, Fair Value Disclosure Segment Reporting [Abstract] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments Operating Segments [Member] Segment Reconciling Items Segment Reconciling Items [Member] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Healthcare Health Care [Member] Business Advisory Business Advisory [Member] Business Advisory [Member] Education [Member] Education [Member] Education [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Components of Segment Information Segment Reporting Information, Profit (Loss) [Abstract] Operating income (loss) Operating Income (Loss) Segment operating income as a percentage of segment revenues Operating Income Loss As Percent Of Revenues Segment operating income (loss) as percent of segment revenues. Revenue from Contract with Customer, Including Assessed Tax Revenue from Contract with Customer, Including Assessed Tax Reimbursable Revenues Reimbursable Revenues Reimbursable Revenues Total revenues and reimbursable expenses Revenues Other operating expenses Other Selling, General and Administrative Expense Gain (Loss) Related To Litigation Settlement And Other Operating Gains Gain (Loss) Related To Litigation Settlement And Other Operating Gains Amount of (gain) loss recognized in settlement of litigation and insurance claims and other operating activities. Also includes the amount of increase (decrease) in the fair value of a contingent consideration liability, including, but not limited to, differences arising upon settlement. Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Other expense, net Nonoperating Income (Expense) Income from continuing operations before income tax expense Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Equity [Abstract] Components of Other Comprehensive Income (Loss), Net of Tax Comprehensive Income (Loss) [Table Text Block] Components of Accumulated Other Comprehensive Income (Loss), Net of Tax Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Income Tax Disclosure [Abstract] Income Tax Disclosure [Table] Income Tax Disclosure [Table] Income Tax Disclosure [Table] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] Adjustments for Error Corrections [Axis] Adjustments for Error Corrections [Axis] Adjustments for Error Correction [Domain] Adjustments for Error Correction [Domain] Income Tax Disclosure [Line Items] Income Tax Disclosure [Line Items] Income Tax Disclosure [Line Items] Effective Income Tax Rate Reconciliation, Percent Effective Income Tax Rate Reconciliation, Percent Income tax expense Income Tax Expense (Benefit) Income from continuing operations before taxes Effective Income Tax Rate Reconciliation, at Statutory Rate, Inclusive of State Income Tax, Percent Statutory Income Tax Rate, Inclusive of State Income Tax, Percent Statutory Income Tax Rate, Inclusive of State Income Tax, Percent Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Payment Arrangement, Percent Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Payment Arrangement, Percent Unrecognized Tax Benefits Unrecognized Tax Benefits Document And Entity Information [Abstract] Document and entity information. Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Title of 12(b) Security Title of 12(b) Security Document Transition Report Document Transition Report Document Quarterly Report Document Quarterly Report Entity Registrant Name Entity Registrant Name Entity Address, Address Line One Entity Address, Address Line One Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Entity Address, Postal Zip Code Entity Address, Postal Zip Code Trading Symbol Trading Symbol Entity Central Index Key Entity Central Index Key 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 Entity File Number Entity File Number City Area Code City Area Code Local Phone Number Local Phone Number Security Exchange Name Security Exchange Name Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Shell Company Entity Shell Company Entity Tax Identification Number Entity Tax Identification Number Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Earnings Per Share [Abstract] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Unvested restricted stock awards Restricted Stock [Member] Share-based Payment Arrangement, Option [Member] Share-based Payment Arrangement, Option [Member] Convertible senior notes Warrants related to the issuance of convertible senior notes Warrant [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Total anti-dilutive securities Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Leases [Abstract] Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months Lessee, Operating Lease, Liability, Payments, Due Year Two Lessee, Operating Lease, Liability, Payments, Due Year Two Lessee, Operating Lease, Liability, Payments, Due Year Three Lessee, Operating Lease, Liability, Payments, Due Year Three Lessee, Operating Lease, Liability, Payments, Due Year Four Lessee, Operating Lease, Liability, Payments, Due Year Four Lessee, Operating Lease, Liability, Payments, Due Year Five Lessee, Operating Lease, Liability, Payments, Due Year Five Lessee, Operating Lease, Liability, Payments, Due after Year Five Lessee, Operating Lease, Liability, Payments, Due after Year Five Lessee, Operating Lease, Liability, Payments, Due Lessee, Operating Lease, Liability, Payments, Due Imputed interest of lease liabilities Lessee Operating Lease Liability Undiscounted Excess Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for operating lease. Operating Lease, Liability Operating Lease, Liability Operating Leases, Future Minimum Payments Due, Next Twelve Months Operating Leases, Future Minimum Payments Due, Next Twelve Months Operating Leases, Future Minimum Payments, Due in Two Years Operating Leases, Future Minimum Payments, Due in Two Years Operating Leases, Future Minimum Payments, Due in Three Years Operating Leases, Future Minimum Payments, Due in Three Years Operating Leases, Future Minimum Payments, Due in Four Years Operating Leases, Future Minimum Payments, Due in Four Years Operating Leases, Future Minimum Payments, Due in Five Years Operating Leases, Future Minimum Payments, Due in Five Years Operating Leases, Future Minimum Payments, Due Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Operating Leases, Future Minimum Payments Due Operating Leases, Future Minimum Payments Due Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activity Derivative Instruments and Hedging Activities Disclosure [Text Block] Interest Expense Recognized [Table] Interest Expense Recognized [Table] Interest Expense Recognized [Table] Interest Expense Recognized [Line Items] Interest Expense Recognized [Line Items] [Line Items] for Interest Expense Recognized [Table] Interest Expense, Debt, Excluding Amortization Interest Expense, Debt, Excluding Amortization Amortization of Debt Discount (Premium) Amortization of Debt Discount (Premium) Amortization of Debt Issuance Costs Amortization of Debt Issuance Costs Interest Expense, Debt Interest Expense, Debt Fair Value Disclosures - Convertible Debt Investment Reconciliation [Abstract] Fair Value Disclosures - Convertible Debt Investment Reconciliation [Abstract] Shorelight Holdings Llc [Member] Fair Value, Recurring [Member] Assets, Fair Value Disclosure Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2014-09 [Member] Accounting Standards Update 2014-09 [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Common Stock [Member] Treasury Stock Treasury Stock [Member] Additional Paid-In Capital Additional Paid-in Capital [Member] Retained Earnings Retained Earnings [Member] Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning Balance, shares Shares, Issued Beginning Balance Stockholders' Equity Attributable to Parent Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Issuance of common stock in connection with: Issuance Of Common Stock In Connection With [Abstract] Issuance Of Common Stock In Connection With [Abstract] Restricted stock awards, net of cancellations, shares Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Restricted stock awards, net of cancellations Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Stock Issued During Period, Value, Stock Options Exercised Stock Issued During Period, Value, Stock Options Exercised Share-based compensation APIC, Share-based Payment Arrangement, Increase for Cost Recognition Shares redeemed for employee tax withholdings, shares Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation Shares redeemed for employee tax withholdings Share-based Payment Arrangement, Decrease for Tax Withholding Obligation New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification Ending Balance, shares Ending Balance Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months Long-term Debt, Maturities, Repayments of Principal in Year Two Long-term Debt, Maturities, Repayments of Principal in Year Two Long-term Debt, Maturities, Repayments of Principal in Year Three Long-term Debt, Maturities, Repayments of Principal in Year Three Long-term Debt, Maturities, Repayments of Principal in Year Four Long-term Debt, Maturities, Repayments of Principal in Year Four Long-term Debt, Maturities, Repayments of Principal in Year Five Long-term Debt, Maturities, Repayments of Principal in Year Five Long-term Debt, Maturities, Repayments of Principal after Year Five Long-term Debt, Maturities, Repayments of Principal after Year Five Fair Value Interest Rate Swaps Designated as Cash Flow Hedging Instruments Schedule of Derivatives Instruments Statements of Financial Performance and Financial Position, Location [Table Text Block] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Prepaid Expenses and Other Current Assets [Member] Prepaid Expenses and Other Current Assets [Member] Other Noncurrent Assets [Member] Other Noncurrent Assets [Member] Accrued Liabilities [Member] Accrued Liabilities [Member] Other Noncurrent Liabilities [Member] Other Noncurrent Liabilities [Member] Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Fair Value interest rate swaps designated as cash flow hedging instruments Interest Rate Cash Flow Hedge Derivative at Fair Value, Net [Abstract] Fair Value (Derivative Asset and Liability) Interest Rate Cash Flow Hedge Derivative at Fair Value, Net Goodwill and Intangible Assets Disclosure [Abstract] Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months Estimated annual intangible assets amortization expense, Year Two Finite-Lived Intangible Assets, Amortization Expense, Year Two Estimated annual intangible assets amortization expense, Year Three Finite-Lived Intangible Assets, Amortization Expense, Year Three Estimated annual intangible assets amortization expense, Year Four Finite-Lived Intangible Assets, Amortization Expense, Year Four Estimated annual intangible assets amortization expense, Year Five Finite-Lived Intangible Assets, Amortization Expense, Year Five Finite-Lived Intangible Assets, Amortization Expense, after Year Five Finite-Lived Intangible Assets, Amortization Expense, after Year Five Carrying Amounts And Estimated Fair Values Of Financial Instruments [Table] Carrying Amounts And Estimated Fair Values Of Financial Instruments [Table] Carrying Amounts And Estimated Fair Values Of Financial Instruments [Table] Carrying Amounts And Estimated Fair Values Of Financial Instruments [Line Items] Carrying Amounts And Estimated Fair Values Of Financial Instruments [Line Items] Carrying Amounts And Estimated Fair Values Of Financial Instruments [Line Items] Net carrying amount Estimated Fair Value Long-term Debt, Fair Value Statement of Comprehensive Income [Abstract] Restatement [Axis] Restatement [Axis] Restatement [Domain] Restatement [Domain] Revenues and reimbursable expenses: Revenues [Abstract] Direct costs and reimbursable expenses (exclusive of depreciation and amortization shown in operating expenses): Direct Operating Costs [Abstract] Cost of Goods and Services Sold Cost of Goods and Services Sold Cost, Depreciation and Amortization Cost, Depreciation and Amortization Reimbursable Expense Reimbursable Expense Reimbursable Expense Total direct costs and reimbursable expenses Cost of Revenue Operating expenses and other gains, net Operating Expenses [Abstract] Selling, general and administrative expenses Selling, General and Administrative Expense Restructuring charges Restructuring Charges Total operating expenses and other gains, net Operating Expenses Operating income Other income (expense), net: Nonoperating Income (Expense) [Abstract] Interest expense, net of interest income Interest Expense Net Of Interest Income The cost of borrowed funds accounted for as interest that was charged against earnings during the period, net of immaterial amounts of interest income recognized during the period associated with banking, investing or other activities. Other income (expense), net Other Nonoperating Income (Expense) Total other expense, net Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Net income Net Income (Loss) Attributable to Parent Net earnings per basic share: Income (Loss) from Continuing Operations, Per Basic Share Income (Loss) from Continuing Operations, Per Basic Share Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share Basic (USD per share) Earnings Per Share, Basic Net earnings per diluted share: Earnings Per Share, Diluted [Abstract] Income (Loss) from Continuing Operations, Per Diluted Share Income (Loss) from Continuing Operations, Per Diluted Share Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Diluted Share Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Diluted Share Earnings Per Share, Diluted Earnings Per Share, Diluted Weighted average shares used in calculating earnings per share: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted average common shares outstanding – basic Weighted Average Number of Shares Outstanding, Basic Weighted average common shares outstanding – diluted Weighted Average Number of Shares Outstanding, Diluted Comprehensive income: Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Foreign currency translation adjustments, net of tax Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Unrealized gain on investment, net of tax Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax Unrealized gain (loss) on cash flow hedging instruments, net of tax Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Other comprehensive income Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Fair Value Disclosures - Contingent Consideration Reconciliation [Abstract] Fair Value Disclosures - Contingent Consideration Reconciliation [Abstract] Change in Fair Value, Reason [Axis] Change in Fair Value, Reason [Axis] Change in Fair Value, Reason [Axis] Change in Fair Value, Reason [Domain] Change in Fair Value, Reason [Domain] [Domain] for Change in Fair Value, Reason [Axis] Foreign Currency Gain (Loss) [Member] Foreign Currency Gain (Loss) [Member] Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Period Increase (Decrease) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Period Increase (Decrease) Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] 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 [Member] Customer Relationships [Member] Trade Names [Member] Trade Names [Member] Technology And Software [Member] Technology And Software [Member] Technology And Software [Member] Noncompete Agreements [Member] Noncompete Agreements [Member] Off-Market Favorable Lease [Member] Off-Market Favorable Lease [Member] Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Intangible assets Finite-Lived Intangible Assets, Net [Abstract] Useful Life (in years) Finite-Lived Intangible Asset, Useful Life Gross Carrying Amount Finite-Lived Intangible Assets, Gross Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Summary of Carrying Amounts of Debt Schedule of Long-term Debt Instruments [Table Text Block] Schedule of Maturities of Long-term Debt Schedule of Maturities of Long-term Debt [Table Text Block] Schedule of Convertible Notes Convertible Debt [Table Text Block] Summary of Interest Expense Recognized Interest Expense Disclosure [Table Text Block] Tabular disclosure of components of interest expense recognized during the period related to the convertible senior notes. Components of interest expense include the contractual interest coupon, the amortization of debt issuance costs, and the amortization of the debt discount. Changes in Carrying Amount of Goodwill Schedule of Goodwill [Table Text Block] Intangible Assets Schedule of Acquired Finite-Lived Intangible Assets by Major Class [Table Text Block] Schedule of Future Amortization Expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Interest rate swap agreement, effective date Derivative, Inception Date Interest rate swap agreement, end date Derivative, Maturity Date Interest rate swap agreement for a notional amount Derivative, Notional Amount Duration of LIBOR Duration Of Libor The duration of LIBOR which is used to calculate the interest received from the counterparty. Percentage of fixed rate Interest Rate Swap Fixed Interest Rate The fixed interest rate we pay to the counterparty of the interest rate swap. Gain (loss) reclassification from accumulated OCI to income, estimate of time to transfer Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimate of Time to Transfer Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Earnings Per Share, Policy Earnings Per Share, Policy [Policy Text Block] Convertible Senior Notes, Policy Accounting For Convertible Senior Notes [Policy Text Block] Disclosure of accounting policy for convertible senior notes including the process of calculating the debt discount and related treatment of the equity and liability components. Derivatives and Hedging, Policy Derivatives, Policy [Policy Text Block] Fair Value of Financial Instruments, Policy Fair Value of Financial Instruments, Policy [Policy Text Block] Segment Reporting, Policy Segment Reporting, Policy [Policy Text Block] Lessee, Leases, Policy Lessee, Leases [Policy Text Block] Revenue from Contract with Customer [Text Block] Revenue from Contract with Customer [Text Block] Foreign currency translation adjustment, before taxes Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax Foreign currency translation adjustment, taxes Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Tax Amount of tax expense (benefit) related to, after reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature. Foreign currency translation adjustment, net of taxes Unrealized gain on investment, before taxes Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax Unrealized gain on investment, tax (expense) benefit Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax Unrealized gain on investment, net of taxes Change in fair value, before taxes Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax Change in fair value, tax (expense) benefit Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax Change in fair value, net of taxes Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Reclassification adjustments into earnings, before taxes Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax Reclassification adjustments into earnings, tax (expense) benefit Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax Reclassification adjustments into earnings, net of taxes Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax Net unrealized gain (loss), before taxes Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax, Portion Attributable to Parent Net unrealized gain (loss), tax (expense) benefit Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax, Portion Attributable to Parent Net unrealized gain (loss), net of taxes Other comprehensive income (loss), before taxes Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent Other comprehensive income (loss), tax (expense) benefit Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Accumulated Other Comprehensive (Income) Loss, Current period change Impact of Adoption - Balance Sheet [Abstract] Impact of Adoption - Balance Sheet [Abstract] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Operating lease right-of-use asset [Member] Operating lease right-of-use asset [Member] Operating lease right-of-use asset [Member] Current maturities of operating lease liabilities [Domain] Operating lease liability current [Member] Operating lease liability current [Member] Other Liabilities [Member] Other Liabilities [Member] Deferred lease incentives [Domain] Deferred rent credit noncurrent [Member] Deferred rent credit noncurrent [Member] Operating lease liabilities, net of current [Domain] Operating lease liability noncurrent [Member] Operating lease liability noncurrent [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] Adjustments for Change in Accounting Principle [Axis] Adjustments for Change in Accounting Principle [Axis] Adjustments for Change in Accounting Principle [Domain] Adjustments for Change in Accounting Principle [Domain] Scenario [Axis] Scenario [Axis] Scenario [Domain] Scenario [Domain] 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, Current Operating Lease, Liability, Current Deferred compensation and other liabilities Deferred Compensation And Other Liabilities Aggregate carrying value, as of the balance sheet date, of the liabilities for all deferred compensation arrangements and all other non current obligations not separately disclosed in the balance sheet payable beyond one year (or the operating cycle, if longer). Operating lease liabilities, net of current portion Deferred Rent Credit, Noncurrent Operating Lease, Liability, Noncurrent Operating Lease, Liability, Noncurrent Statement of Financial Position [Abstract] Common stock, par value (USD per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (shares) Common Stock, Shares Authorized Common stock, shares issued (shares) Common Stock, Shares, Issued Treasury stock, shares (shares) Treasury Stock, Shares Schedule of Supplemental Balance Sheet Information for Operating Leases Schedule of Supplemental Balance Sheet Information for Operating Leases [Table Text Block] Schedule of Supplemental Balance Sheet Information for Operating Leases [Table Text Block] Lease, Cost Lease, Cost [Table Text Block] Lessee, Operating Lease, Liability, Maturity Lessee, Operating Lease, Liability, Maturity [Table Text Block] Schedule of Supplemental Operating Lease Information Schedule of Supplemental Operating Lease Information [Table Text Block] [Table Text Block] for Schedule of Supplemental Operating Lease Information [Table] Amortization of Intangible Assets Amortization of Intangible Assets Commitments and Contingencies Disclosure [Abstract] Commitments, Contingencies and Guarantees Commitments Contingencies and Guarantees [Text Block] Disaggregation of Revenue [Abstract] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Contract with Customer, Basis of Pricing [Axis] Contract with Customer, Basis of Pricing [Axis] Contract with Customer, Basis of Pricing [Domain] Contract with Customer, Basis of Pricing [Domain] Fixed-price Contract [Member] Fixed-price Contract [Member] Time-and-materials Contract [Member] Time-and-materials Contract [Member] Performance-based [Member] Performance-based [Member] Performance-based [Member] Software Service, Support and Maintenance Arrangement [Member] Software Service, Support and Maintenance Arrangement [Member] Employee Type [Axis] Employee Type [Axis] Employee Type [Axis] Employee Type [Domain] Employee Type [Domain] [Domain] for Employee Type [Axis] Full-time Billable Consultants [Member] Full-time Billable Consultants [Member] Full-time Billable Consultants [Member] Full-time Equivalents [Member] Full-time Equivalents [Member] Full-time Equivalents [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 over Time [Member] Transferred over Time [Member] Transferred at Point in Time [Member] Transferred at Point in Time [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Income Taxes Income Tax Disclosure [Text Block] Financing Arrangements Debt Disclosure [Text Block] Reconciliation of Basic and Diluted Earnings Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Summary of Anti-dilutive Securities Excluded from Computation of Weighted Average Common Stock Equivalents Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Schedule of Goodwill [Table] Schedule of Goodwill [Table] Goodwill [Line Items] Goodwill [Line Items] Goodwill Goodwill, Gross Accumulated impairment losses Goodwill, Impaired, Accumulated Impairment Loss Goodwill [Roll Forward] Goodwill [Roll Forward] Goodwill, net beginning balance Goodwill Goodwill, Foreign Currency Translation Gain (Loss) Goodwill, Foreign Currency Translation Gain (Loss) Goodwill, net ending balance Receivables from Major Customer Percentage Receivables from Major Customer Percentage The percentage of combined consolidated receivables from clients, net and unbilled services, net generated by a single customer above the 10% concentration risk percentage. Number of Operating Segments Number of Operating Segments Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Senior secured credit facility Senior Secured Credit Facility [Member] Senior Secured Credit Facility [Member] Promissory Note due 2024 [Member] Promissory Note due 2024 [Member] Promissory Note due 2024 [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Long-term Debt, Current Maturities Long-term Debt, Current Maturities Long-term debt, net of current portion Long-term Debt, Excluding Current Maturities Restructuring and Related Activities [Abstract] Schedule of Restructuring and Related Costs [Table] Schedule of Restructuring and Related Costs [Table] Accounting Standards Update 2016-02 [Member] Accounting Standards Update 2016-02 [Member] Restructuring Type [Axis] Restructuring Type [Axis] Type of Restructuring [Domain] Type of Restructuring [Domain] Employee Severance [Member] Employee Severance [Member] Office Space Reductions [Member] Office Space Reductions [Member] Office Space Reductions [Member] Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Restructuring reserve Restructuring Reserve Restructuring and Related Cost, Incurred Cost Restructuring and Related Cost, Incurred Cost Payments for Restructuring Payments for Restructuring Restructuring Reserve, Accrual Adjustment Restructuring Reserve, Accrual Adjustment Earnings Per Share Earnings Per Share [Text Block] Change in Contract with Customer, Asset [Abstract] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Change in Contract with Customer, Asset and Liability [Abstract] Contract with Customer, Asset, after Allowance for Credit Loss Contract with Customer, Asset, after Allowance for Credit Loss Contract Asset, Period Increase (Decrease) Contract Asset, Period Increase (Decrease) Amount of increase (decrease) in the right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than the passage of time. Deferred revenues Deferred Revenue, Current Increase (decrease) in deferred revenues Deferred Revenue, Period Increase (Decrease) Deferred Revenue, Revenue Recognized Deferred Revenue, Revenue Recognized Statement of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Adjustments to reconcile net income to net cash provided by (used in) operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Operating Lease, Impairment Loss Operating Lease, Impairment Loss Share-based compensation Share-based Payment Arrangement, Noncash Expense Amortization of debt discount and issuance costs Amortization of Debt Issuance Costs and Discounts Allowances For Doubtful Accounts And Unbilled Services Accounts Receivable, Credit Loss Expense (Reversal) Gain (Loss) on Disposition of Business Gain (Loss) on Disposition of Business Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability Changes in operating assets and liabilities, net of acquisitions and divestiture: Increase (Decrease) in Operating Capital [Abstract] (Increase) decrease in receivables from clients, net Increase (Decrease) in Accounts Receivable (Increase) decrease in unbilled services, net Increase (Decrease) in Unbilled Receivables (Increase) decrease in current income tax receivable / payable, net Increase (Decrease) in Income Taxes Payable, Net of Income Taxes Receivable (Increase) decrease in other assets Increase (Decrease) in Other Operating Assets Increase (decrease) in accounts payable and other liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Increase (decrease) in accrued payroll and related benefits Increase (Decrease) in Employee Related Liabilities Increase (decrease) in deferred revenues Increase (Decrease) in Deferred Revenue Net cash provided by (used in) 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 [Abstract] Purchases of property and equipment, net Payments to Acquire Property, Plant, and Equipment Investment in life insurance policies Payments for (Proceeds from) Life Insurance Policies Purchases of businesses, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Capitalization of internally developed software costs Payments to Develop Software Costs in Excess of Billings, Current Costs in Excess of Billings, Current Proceeds from Sale and Collection of Notes Receivable Proceeds from Sale and Collection of Notes Receivable Proceeds from Divestiture of Businesses, Net of Cash Divested Proceeds from Divestiture of Businesses, Net of Cash Divested 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 [Abstract] Proceeds from exercise of stock options Proceeds from Stock Options Exercised Shares redeemed for employee tax withholdings Payment, Tax Withholding, Share-based Payment Arrangement Proceeds from borrowings under credit facility Proceeds from Long-term Lines of Credit Repayments of debt Repayments of Long-term Debt Payments of Debt Issuance Costs Payments of Debt Issuance Costs Payment of Contingent Consideration Liabilities Payment of Contingent Consideration Liabilities Payment of Contingent Consideration Liabilities Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations Effect of exchange rate changes on cash Effect of Exchange Rate on Cash and Cash Equivalents Net decrease in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of the period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at end of the period Supplemental disclosure of cash flow information: Supplemental Cash Flow Information [Abstract] Non-cash investing and financing activities: Noncash Investing and Financing Items [Abstract] Property and equipment expenditures and capitalized software included in accounts payable and accrued expenses Capital Expenditures Incurred but Not yet Paid Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Contingent consideration related to business acquisitions Business Combination, Contingent Consideration, Liability Restructuring Charges Restructuring and Related Activities Disclosure [Text Block] Restructuring Plan [Axis] Restructuring Plan [Axis] Restructuring Plan [Domain] Restructuring Plan [Domain] Middleton, Wisconsin [Member] Middleton, Wisconsin [Member] Exit of office space in Middleton, Wisconsin Houston, Texas [Member] Houston, Texas [Member] Exit of office space in Houston, Texas San Francisco, CA [Member] San Francisco, CA [Member] Exit of office space in San Francisco, California Corporate, Non-Segment [Member] Corporate, Non-Segment [Member] Huron Legal [Member] Huron Legal [Member] Huron Legal [Member] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name [Domain] Disposal Group Name [Domain] Discontinued Operations [Member] Discontinued Operations [Member] Other Restructuring [Member] Other Restructuring [Member] Restructuring Charges [Abstract] Restructuring Charges [Abstract] Restructuring and Related Cost, Accelerated Depreciation Restructuring and Related Cost, Accelerated Depreciation New Accounting Pronouncements and Changes in Accounting Principles [Abstract] New Accounting Pronouncements New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Operating Lease, Payments Operating Lease, Payments Operating Lease, Weighted Average Remaining Lease Term Operating Lease, Weighted Average Remaining Lease Term Operating Lease, Weighted Average Discount Rate, Percent Operating Lease, Weighted Average Discount Rate, Percent Components of Segment Information Schedule of Segment Reporting Information, by Segment [Table Text Block] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] New Accounting Pronouncements [Abstract] New Accounting Pronouncements [Abstract] Schedule of New Accounting Pronouncements and Changes in Accounting Principles Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block] Assets Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Receivables from clients, net Accounts Receivable, after Allowance for Credit Loss, Current Income tax receivable Income Taxes Receivable, Current Prepaid Expense and Other Assets, Current Prepaid Expense and Other Assets, Current Total current assets Assets, Current Property and equipment, net Property, Plant and Equipment, Net Deferred Tax Assets, Net, Noncurrent Deferred Tax Assets, Net, Noncurrent Long-term investment Other non-current assets Other Assets, Noncurrent Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Goodwill Total assets Assets Liabilities and stockholders’ equity Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued expenses and other current liabilities Accrued Liabilities, Current Accrued payroll and related benefits Employee-related Liabilities, Current Business Combination, Contingent Consideration, Liability, Current Business Combination, Contingent Consideration, Liability, Current Long-term Debt, Current Maturities Total current liabilities Liabilities, Current Non-current liabilities: Liabilities, Noncurrent [Abstract] Business Combination, Contingent Consideration, Liability, Noncurrent Business Combination, Contingent Consideration, Liability, Noncurrent Deferred income taxes, net Deferred Tax Liabilities, Net, Noncurrent Total non-current liabilities Liabilities, Noncurrent Commitments and contingencies Commitments and Contingencies Stockholders’ equity Stockholders' Equity Attributable to Parent [Abstract] Common stock Common Stock, Value, Issued Treasury stock Treasury Stock, Value Additional paid-in capital Additional Paid in Capital, Common Stock Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Total stockholders’ equity Total liabilities and stockholders’ equity Liabilities and Equity Schedule of Restructuring Reserve by Type of Cost Schedule of Restructuring Reserve by Type of Cost [Table Text Block] Leases of Lessee Disclosure [Text Block] Leases of Lessee Disclosure [Text Block] Segment Information Segment Reporting Disclosure [Text Block] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Aircraft [Domain] Aircraft [Domain] Note Hedge Note Hedge [Member] Note Hedge [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] LIBOR London Interbank Offered Rate (LIBOR) [Member] Base Rate [Member] Base Rate [Member] Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Interest Rate, Stated Percentage Debt instrument maturity date Debt Conversion, Original Debt, Due Date of Debt Number of common shares converted upon debt conversion for each $1000 principal amount Debt Instrument, Convertible, Conversion Ratio Principal amount of notes per conversion Principal Amount Per Note The principal, or par, value of each note issued. Conversion price of convertible notes Debt Instrument, Convertible, Conversion Price Optional right of debt instrument holders to convert debt instrument into cash, portion of principal amount Percentage Of Principal Paid Upon Exercise Of Put Percentage of principal amount required to be paid upon a debt holder's exercise of the put option following a fundamental change as defined in the indenture. Earliest conversion date Debt Instrument Convertible Date The earliest date on which the debt instrument can be converted into equity if none of the other conversion conditions have been met. Number of least trading days required within consecutive trading days Debt Instrument, Convertible, Threshold Consecutive Trading Days Number of consecutive trading days Number Of Consecutive Period Of Trading Number of consecutive trading days during the last month of the preceding quarter in which the closing price on 20 such days must meet the stock price threshold defined in the indenture. Percentage of applicable conversion price Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger Number of consecutive business days following consecutive trading days Debt instrument, Convertible, Threshold of Consecutive Business Days Following Consecutive Trading Days Debt instrument, Convertible, Threshold of Consecutive Business Days Following Consecutive Trading Days Concentration risk percentage Minimum Trading Price Percentage The minimum trading price as a percentage of the product of the last reported share price and the conversion rate of the notes. Effective interest rate of debt Debt Instrument, Interest Rate, Effective Percentage Debt Instrument, Convertible, Remaining Discount Amortization Period Debt Instrument, Convertible, Remaining Discount Amortization Period Liability issuance costs Debt Issuance Costs Assigned To Liability Total debt issuance costs assigned to the liability component of the convertible senior notes based on the relative fair value of the liability component to the total value of the notes issued. Equity issuance costs Issuance Costs Assigned To Equity Total issuance costs assigned to the equity component of the convertible senior notes based on the relative fair value of the equity component to the total value of the notes issued. Common stock purchased Common Stock Underlying Convertible Senior Note And Related Transactions The number of shares of common stock underlying the convertible senior notes as well as the warrants and convertible note hedge transactions purchased concurrently with the issuance of the convertible senior notes. Aggregate amount for convertible hedge Payments For Note Hedges The cash outflow associated with the amount paid for convertible senior note hedges. Common stock price per share Class of Warrant or Right, Exercise Price of Warrants or Rights Aggregate proceeds from the sale of warrants Proceeds from Issuance of Warrants Deferred tax liability Deferred tax asset Deferred Tax Assets, Net of Valuation Allowance, Noncurrent Revolving Credit facility Line of Credit Facility, Current Borrowing Capacity Credit agreement expiration date Line of Credit Facility, Expiration Date Option to increase revolving credit facility Optional Increase In Revolver Optional increase in revolver. Maximum principle amount Line of Credit Facility, Maximum Borrowing Capacity Interest rate on borrowings Debt Instrument, Basis Spread on Variable Rate Convertible debt maturity term Required Payment On Revolver Related To Convertible Debt Maturity Term Required payment on revolver related to convertible debt maturity term. Percentage of other equity interests in domestic subsidiaries Percentage Of Pledged Voting Stock In Domestic Subsidiaries The percentage of pledged voting stock or other equity instruments in the domestic subsidiaries to secure the revolver and term loan. Percentage of other equity interests in foreign subsidiaries Percentage Of Pledged Voting Stock In Foreign Subsidiaries The percentage of pledged voting stock or other equity instruments in the foreign subsidiaries to secure the revolver and term loan. Debt Instrument, Covenant, Consolidated Leverage Ratio, Minimum Debt Instrument, Covenant, Consolidated Leverage Ratio, Minimum Debt Instrument, Covenant, Consolidated Leverage Ratio, Minimum Maximum consolidated leverage ratio Debt Instrument, Covenant, Consolidated Leverage Ratio, Maximum Debt Instrument, Covenant, Consolidated Leverage Ratio, Maximum Minimum consolidated interest coverage ratio Debt Instrument, Covenant, Interest Coverage Ratio, Minimum Debt Instrument, Covenant, Interest Coverage Ratio, Minimum Actual consolidated leverage ratio Debt Instrument, Covenant, Actual Consolidated Leverage Ratio Debt Instrument, Covenant, Actual Consolidated Leverage Ratio Actual interest coverage ratio Debt Instrument, Covenant, Actual Interest Coverage Ratio Debt Instrument, Covenant, Actual Interest Coverage Ratio Percentage of weighted average interest rate of borrowings Debt, Weighted Average Interest Rate Outstanding letters of credit Letters of Credit Outstanding, Amount Unused borrowing capacity under Credit Agreement Line of Credit Facility, Remaining Borrowing Capacity Repayment of Principal at Maturity Date Repayment of Principal at Maturity Date Repayment of Principal at Maturity Date Restructuring Charges Operating Lease, Cost Operating Lease, Cost Short-term Lease, Cost Short-term Lease, Cost Variable Lease, Cost Variable Lease, Cost Sublease Income Sublease Income Lease, Cost Lease, Cost Goodwill and Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Financial Assets and Liabilities Measured at Fair Value on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Summary of Carrying Amount and Estimated Fair Value of Convertible Senior Notes Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block] Commitments And Contingencies [Table] Commitments And Contingencies [Table] Commitments And Contingencies [Table] Commitments And Contingencies [Line Items] Commitments And Contingencies [Line Items] Commitments And Contingencies [Line Items] Gain (Loss) Related to Litigation Settlement Gain (Loss) Related to Litigation Settlement Guarantees in the form of letters of credit Description of Business Nature of Operations [Text Block] Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Weighted average common stock equivalents Weighted Average Number Diluted Shares Outstanding Adjustment Weighted average common shares outstanding – diluted Net earnings per basic share: Earnings Per Share, Basic and Diluted [Abstract] Basic (USD per share) Diluted (USD per share) Accelerated Share Repurchases [Table] Accelerated Share Repurchases [Table] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] Share Repurchase Program [Member] Share Repurchase Program [Member] Share Repurchase Program [Member] Accelerated Share Repurchases [Line Items] Accelerated Share Repurchases [Line Items] Share repurchase authorized amount Stock Repurchase Program, Authorized Amount Stock Repurchase Program, Remaining Authorized Repurchase Amount Stock Repurchase Program, Remaining Authorized Repurchase Amount Fair Value of Financial Instruments Fair Value Disclosures [Text Block] Foreign Currency Translation Adjustments, Beginning balance Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax Foreign Currency Translation Adjustments, Ending balance Net Unrealized Gain (Loss) on Investment, Beginning balance AOCI, Debt Securities, Available-for-sale, Adjustment, after Tax Net Unrealized Gain (Loss) on Investment, Ending balance Net Unrealized Losses on Derivatives, Beginning balance Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax Net Unrealized Losses on Derivatives, Ending balance Accumulated Other Comprehensive Income (Loss), Beginning balance Accumulated Other Comprehensive Income (Loss), Ending balance Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Restructuring Charges [Member] Restructuring Charges [Member] Leasehold Improvements [Member] Leasehold Improvements [Member] Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Lease, Cost Operating Leases, Future Minimum Payments Receivable Operating Leases, Future Minimum Payments Receivable Operating Leases, Rent Expense, Net Operating Leases, Rent Expense, Net Lessee, Operating Lease, Renewal Term Lessee, Operating Lease, Renewal Term