Insights Insights [Member] -- None. No documentation exists for this element. -- Accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Statistical Measurement [Domain] Statistical Measurement [Domain] Other current assets Other Current Assets [Member] Schedule of Notional Amounts of Outstanding Derivative Positions Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Operating Lease, Liability, Current, Statement of Financial Position [Extensible List] Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Award Timing Predetermined Award Timing Predetermined [Flag] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Entity File Number Entity File Number Additional Paid-In Capital Additional Paid-in Capital [Member] Interest rate swaps Interest rate swap contracts Interest Rate Swap [Member] Payments of deferred financing fees Payments of Financing Costs Tabular List, Table Tabular List [Table Text Block] Leases [Abstract] Adoption of new accounting standard and Accounting standards issued but not yet adopted New Accounting Pronouncements, Policy [Policy Text Block] Goodwill [Line Items] Goodwill [Line Items] Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Other expenses Other Expenses Basic (in dollars per share) Basic income per share (in dollars per share) Earnings Per Share, Basic Adjustment to Compensation: Adjustment to Compensation [Axis] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Accounts payable and accrued and other liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Liabilities: Liabilities, Fair Value Disclosure [Abstract] Revenue and Related Matters Revenue from Contract with Customer [Text Block] Schedule of Segment Reporting Information by Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Axis] Remaining performance obligation, amount Revenue, Remaining Performance Obligation, Amount Adjustment to Compensation, Amount Adjustment to Compensation Amount Other assets Increase (Decrease) in Other Operating Assets Principles of consolidation Consolidation, Policy [Policy Text Block] Stock-based compensation expense Share-Based Payment Arrangement, Noncash Expense Employee Stock Option Share-Based Payment Arrangement, Option [Member] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Line of credit facility, additional borrowing capacity Line of Credit Facility, Additional Borrowing Capacity Line of Credit Facility, Additional Borrowing Capacity Total Stockholders’ Equity Beginning balance Ending balance Equity, Attributable to Parent Measurement Frequency [Axis] Measurement Frequency [Axis] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Other comprehensive income (loss), net of tax: Other comprehensive income (loss) activity during the period: Other Comprehensive Income (Loss), Net of Tax [Abstract] Insider Trading Policies and Procedures [Line Items] Stock-based compensation expense Share-Based Payment Arrangement, Expense Common stock, shares authorized (in shares) Common Stock, Shares Authorized Hedging Designation [Domain] Hedging Designation [Domain] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Current assets: Assets, Current [Abstract] Total Liabilities and Stockholders’ Equity Liabilities and Equity Proceeds from event cancellation insurance claims Unusual or Infrequent Item, or Both, Insurance Proceeds Fair Value, Recurring Fair Value, Recurring [Member] Defined Benefit Pension Plans Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Contractual annualized interest rate Line of Credit Facility, Interest Rate at Period End Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) [Table] Liabilities and Stockholders’ Equity Liabilities and Equity [Abstract] Cover page. Cover [Abstract] Reclassifications from AOCL to income Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent 2024 Credit Agreement 2024 Credit Agreement [Member] 2024 Credit Agreement Maximum Maximum [Member] Remaining amortization period Finite-Lived Intangible Asset, Useful Life Finite-lived intangible assets, net Finite-Lived Intangible Assets, Net Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Debt Instrument [Line Items] Debt Instrument [Line Items] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Treasury Stock Treasury Stock, Common [Member] 2022 Acquisition 2022 Acquisition [Member] 2022 Acquisition Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Pay vs Performance Disclosure [Line Items] Net balance sheet carrying amount Debt, Long-Term and Short-Term, Combined Amount Total operating lease liabilities included in the Condensed Consolidated Balance Sheets Operating Lease, Liability Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Debt Instrument, Redemption, Period One Debt Instrument, Redemption, Period One [Member] Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Income before income taxes Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Entity Shell Company Entity Shell Company Weighted average effective rate Long-Term Debt, Weighted Average Interest Rate, over Time Other Other Reportable Segment [Member] Other Reportable Segment Percentage of principal amount redeemed Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed Schedule of Carrying Values and Estimated Fair Values of Debt Instruments Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block] Other liabilities Other Liabilities, Noncurrent Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Deferred revenues Increase (Decrease) in Deferred Revenue Debt Instrument, Redemption, Period [Domain] Debt Instrument, Redemption, Period [Domain] Statement of Stockholders' Equity [Abstract] Goodwill impairment Impairment loss Goodwill Impairment Loss Goodwill, Impairment Loss Operating Segments Operating Segments [Member] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Current portion of long-term debt Long-Term Debt, Current Maturities Company Selected Measure Amount Company Selected Measure Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Name Measure Name Letter of Credit Letter of Credit [Member] Schedule Of Stock-Based Compensation Expense By Expense Category Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Accounts payable and accrued liabilities Operating Lease, Liability, Current Finite-lived Intangible Assets [Roll Forward] Finite-Lived Intangible Assets [Roll Forward] Supplemental Balance Sheet Information Liabilities, Leases [Table Text Block] Liabilities, Leases Document Fiscal Period Focus Document Fiscal Period Focus Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Unsecured Debt Unsecured Debt [Member] Award Timing Method Award Timing Method [Text Block] Award Type [Axis] Award Type [Axis] Non-current deferred revenues recorded in Other liabilities Contract with Customer, Liability, Noncurrent Foreign Currency Translation Adjustments Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Open Market Purchases, Excluded Open Market Purchases, Excluded [Member] Open Market Purchases, Excluded Carrying Amount Long-Term Debt Total Assets Assets 2026 Finite-Lived Intangible Asset, Expected Amortization, Year One Trading Symbol Trading Symbol Cash and cash equivalents and restricted cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Geographical [Domain] Geographical [Domain] Entity Address, City or Town Entity Address, City or Town Operating activities: Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Effects of exchange rates on cash and cash equivalents Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Other International Other International [Member] -- None. No documentation exists for this element. -- Employee Service Share-based Compensation, Allocation of Recognized Period Costs, Report Line [Domain] Income Statement Location [Domain] Statement of Income Location, Balance [Domain] Restricted stock units Restricted Stock Units (RSUs) [Member] Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Assets: Assets, Fair Value Disclosure [Abstract] 2029 Finite-Lived Intangible Asset, Expected Amortization, Year Four Entity Emerging Growth Company Entity Emerging Growth Company Changes in assets and liabilities, net of acquisitions and divestitures: Increase (Decrease) in Operating Capital, Net of Acquisition [Abstract] -- None. No documentation exists for this element. -- Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Right-of-use assets obtained in exchange for new operating lease liabilities Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Other Other Long Term Debt [Member] Other Long Term Debt [Member] Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Derivative reclassifications Total expense, net Derivative, Gain (Loss) on Derivative, Net Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Business Combination [Domain] Business Combination [Domain] PEO PEO [Member] Schedule of Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Economic Development Loan 2 Economic Development Loan 2 [Member] Economic Development Loan 2 [Member] Schedule of Estimated Future Amortization Expense by Year Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract] Accumulated Earnings Retained Earnings [Member] Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Entity Address, Postal Zip Code Entity Address, Postal Zip Code Restatement Determination Date Restatement Determination Date Share-based Payment Arrangement [Abstract] Share-Based Payment Arrangement [Abstract] Cash and cash equivalents and restricted cash, beginning of period Cash and cash equivalents, end of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Income Statement [Abstract] Income Statement [Abstract] Cost for subleasing activities Operating Lease, Cost, Subleasing Activities Operating Lease, Cost, Subleasing Activities Provision for income taxes Income Tax Expense (Benefit) Change in AOCL before reclassifications to income OCI, before Reclassifications, before Tax, Attributable to Parent Additional interest above base rate Debt Instrument, Basis Spread on Variable Rate Interest expense, net Interest Expense [Member] Europe, Middle East and Africa Europe Middle East Africa [Member] -- None. No documentation exists for this element. -- Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Product and Service [Domain] Product and Service [Domain] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] 2028 Notes Senior Notes Due 2028 [Member] Senior Notes Due 2028 Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Total Liabilities Liabilities, Fair Value Disclosure Interest rate swap contracts total notional value Notional Amounts Derivative, Notional Amount Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Digital Markets Reporting Unit Digital Markets Reporting Unit [Member] Digital Markets Reporting Unit Connecticut Economic Development Program Connecticut Economic Development Program [Member] -- None. No documentation exists for this element. -- Equity, Class of Treasury Stock [Line Items] Equity, Class of Treasury Stock [Line Items] City Area Code City Area Code Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] All Trading Arrangements All Trading Arrangements [Member] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Accrued liabilities Accrued Liabilities Current [Member] -- None. No documentation exists for this element. -- Class of Treasury Stock [Table] Class of Treasury Stock [Table] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Schedule for Contract with Customer, Asset and Liability Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] Investing activities: Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Cash provided by operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Debt instrument, issue price, percent Debt Instrument, Issue Price, Percentage Debt Instrument, Issue Price, Percentage Debt term Debt Instrument, Term Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Total lease cost, net Lease, Cost Selling, general and administrative Selling, General and Administrative Expenses [Member] Cost of services and product development Cost of Sales [Member] Goodwill Beginning balance Ending balance Goodwill Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Lease Costs Lease, Cost [Table Text Block] PEO Total Compensation Amount PEO Total Compensation Amount Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Depreciation Depreciation 2025 (remaining three months) Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year Equity Components [Axis] Equity Components [Axis] Sublease income Sublease Income Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Number of reportable segments Number of Reportable Segments Deferred consideration Business Combination, Deferred Consideration Business Combination, Deferred Consideration Accumulated impairment losses Goodwill, Impaired, Accumulated Impairment Loss Other Performance Measure, Amount Other Performance Measure, Amount Contract liabilities: Contract with Customer, Liability [Abstract] Entity Address, State or Province Entity Address, State or Province Loss on impairment of lease related assets Loss on impairment of lease related assets, net Operating Lease, Impairment Loss Variable Rate Component One Variable Rate Component One [Member] Variable Rate Component One Deferred commissions Increase (Decrease) in Deferred Charges Total current liabilities Liabilities, Current Net (decrease) increase in cash and cash equivalents and restricted cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Excluding Exchange Rate Effect, Including Discontinued Operation Derivative Instrument [Axis] Derivative Instrument [Axis] Individual: Individual [Axis] Leases Lessee, Finance Leases [Text Block] Cash used in investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Revenue, remaining performance obligation, expected timing of satisfaction, period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] 2029 Notes Senior Notes Due 2029 [Member] Senior Notes Due 2029 Document Fiscal Year Focus Document Fiscal Year Focus Basis of presentation Basis of Accounting, Policy [Policy Text Block] Operating lease right-of-use assets Operating Lease, Right-of-Use Asset Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Payments on long-term debt Repayments of Long-Term Debt Effective income tax rate Effective Income Tax Rate Reconciliation, Percent Entity Interactive Data Current Entity Interactive Data Current Operating lease cost Operating Lease, Cost Revenue recognition Revenue from Contract with Customer [Policy Text Block] Segment Information Segment Reporting Disclosure [Text Block] Schedule of Goodwill [Table] Goodwill [Table] 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] Not Designated as Hedging Instrument Not Designated as Hedging Instrument [Member] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Interest rate swaps – net change in deferred gain or loss Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Parent Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Amortization of intangibles Amortization of Intangible Assets Selling, general and administrative Selling, General and Administrative Expense Common share repurchases (including excise tax) Stock Repurchased During Period, Value Schedule Of The Changes In Accumulated Other Comprehensive Loss By Component (Net Of Tax) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Depreciation and amortization Depreciation, Depletion and Amortization Additions to property, equipment and leasehold improvements Payments for Capital Improvements Stock repurchase program, additional authorized amount Stock Repurchase Program, Additional Authorized Amount Stock Repurchase Program, Additional Authorized Amount Other assets Other Assets, Noncurrent Entity Central Index Key Entity Central Index Key PEO Name PEO Name Revenues Revenues Variable Rate Components [Domain] Variable Rate Components [Domain] Variable Rate Components [Domain] Gain on de-designated swaps Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Open Market Purchases Open Market Purchases [Member] Open Market Purchases Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Revolving credit facility Revolving Credit Facility [Member] Variable Rate Component Two Variable Rate Component Two [Member] Variable Rate Component Two Arrangement Duration Trading Arrangement Duration Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Deferred revenues Deferred revenues (current liability) Contract with Customer, Liability, Current Segments [Axis] Segments [Axis] Prepaid expenses and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Exercise Price Award Exercise Price Entity Filer Category Entity Filer Category Local Phone Number Local Phone Number Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Fees receivable, gross Accounts Receivable, before Allowance for Credit Loss, Current Stock-Based Compensation Share-Based Payment Arrangement [Text Block] Cash receipts from sublease arrangements Proceeds from Lease Payment, Operating Activity Option to terminate, term (in years) Lessee, Operating Lease, Option to Terminate, Term Lessee, Operating Lease, Option to Terminate, Term Assets Assets [Abstract] Long-term debt, net of deferred financing fees Long-Term Debt, Excluding Current Maturities Credit Facility [Axis] Credit Facility [Axis] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Balance Sheet Location [Axis] Statement of Financial Position Location, Balance [Axis] 2028 Finite-Lived Intangible Asset, Expected Amortization, Year Three Debt Instrument [Axis] Debt Instrument [Axis] Fair Value Disclosures Fair Value Disclosures [Text Block] Credit Facility [Domain] Credit Facility [Domain] Gross cost Finite-Lived Intangible Assets, Gross Stockholders’ Equity Equity, Attributable to Parent [Abstract] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Entity Address, Address Line One Entity Address, Address Line One Entity Address, Address Line Two Entity Address, Address Line Two Accumulated Other Comprehensive Loss, Net Total AOCI Attributable to Parent [Member] Debt instrument, fixed interest rate Debt Instrument, Interest Rate, Stated Percentage Fees receivable, allowance Accounts Receivable, Allowance for Credit Loss, Current Operating lease liabilities Operating lease liabilities Operating Lease, Liability, Noncurrent Derivatives and Hedging Derivative Instruments and Hedging Activities Disclosure [Text Block] Fair Value as of Grant Date Award Grant Date Fair Value Product and content delivery expenses Product And Content Delivery Expenses Product And Content Delivery Expenses Entity Registrant Name Entity Registrant Name Variable Rate Components [Axis] Variable Rate Components [Axis] Variable Rate Components Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table] Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table] Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Personnel expenses Labor and Related Expense Dilutive effect of outstanding awards associated with stock-based compensation plans (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Total costs and expenses Costs and Expenses Document Quarterly Report Document Quarterly Report Total Assets Assets, Fair Value Disclosure Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Schedule of Debt Schedule of Debt [Table Text Block] Title Trading Arrangement, Individual Title Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Schedule of Amortizable Intangible Assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Restatement Determination Date: Restatement Determination Date [Axis] Acquisition of business Payments to Acquire Businesses, Gross Non-PEO NEO Non-PEO NEO [Member] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Reporting Unit [Axis] Reporting Unit [Axis] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Other Other Intangible Assets [Member] Name Trading Arrangement, Individual Name Award Type [Domain] Award Type [Domain] Unrealized Loss Recorded in AOCL, net of tax Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax Equity Awards Adjustments Equity Awards Adjustments [Member] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Compensation Amount Outstanding Recovery Compensation Amount Aggregate principal amount Debt Instrument, Face Amount Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Revenue recognized previously attributable to deferred revenues Contract with Customer, Liability, Revenue Recognized Share Repurchase Program [Axis] Share Repurchase Program [Axis] Reporting Unit [Domain] Reporting Unit [Domain] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Name Awards Close in Time to MNPI Disclosures, Individual Name Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Revenues: Revenues [Abstract] Stock-based compensation expense APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Accumulated other comprehensive loss, net Accumulated Other Comprehensive Income (Loss), Net of Tax Types of Financial Instruments [Domain] Financial Instruments [Domain] Conferences Conferences Conferences [Member] -- None. No documentation exists for this element. -- Segments [Domain] Segments [Domain] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs, by Report Line [Axis] Income Statement Location [Axis] Statement of Income Location, Balance [Axis] Remaining borrowing capacity Line of Credit Facility, Remaining Borrowing Capacity Cash and Cash Equivalent [Table] Cash and Cash Equivalent [Table] Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Denominator: Denominator: [Abstract] -- None. No documentation exists for this element. -- Balance Sheet Location [Domain] Statement of Financial Position Location, Balance [Domain] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Minimum Minimum [Member] Company Selected Measure Name Company Selected Measure Name Senior Notes Senior Notes [Member] Debt Debt Disclosure [Text Block] Preferred stock, $0.01 par value, 5,000,000 shares authorized; none issued or outstanding Preferred Stock, Value, Issued Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Cash paid for amounts included in the measurement of operating lease liabilities Operating Lease, Payments Stock appreciation rights Stock Appreciation Rights (SARs) [Member] All Executive Categories All Executive Categories [Member] Stockholders' Equity Note [Abstract] Stockholders' Equity Note [Abstract] Common stock, $0.0005 par value, 250,000,000 shares authorized; 163,602,067 shares issued for both periods Common Stock, Value, Issued Goodwill [Roll Forward] Goodwill [Roll Forward] Contingencies Commitments and Contingencies Disclosure [Text Block] Fair Value Asset (Liability), Net Derivative Assets (Liabilities), at Fair Value, Net Diluted (in shares) Shares used in the calculation of diluted income per share (in shares) Weighted Average Number of Shares Outstanding, Diluted Segments Segment Reporting, Policy [Policy Text Block] Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Derivative [Table] Derivative [Table] Business Combination [Axis] Business Combination [Axis] Entity Small Business Entity Small Business Schedule of Disaggregation of Revenue by Reportable Segment Revenue from External Customers by Geographic Areas [Table Text Block] Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Preferred stock, shares outstanding (in shares) Preferred Stock, Shares Outstanding Document Transition Report Document Transition Report Underlying Securities Award Underlying Securities Amount Equity Component [Domain] Equity Component [Domain] Document Period End Date Document Period End Date PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Income Taxes Income Tax Disclosure [Text Block] Percent of target bonus charges allocated to segments Segment Reporting Information, Percent of Target Bonus Charges Allocated to Segments Segment Reporting Information, Percent of Target Bonus Charges Allocated to Segments Proceeds from revolving credit facility Proceeds from Lines of Credit Deferred commissions Other Deferred Costs, Net Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Revenue from Contract with Customer [Abstract] Hedging Designation [Axis] Hedging Designation [Axis] Fair Value Debt Instrument, Fair Value Disclosure Document Type Document Type Computation of Earnings Per Share Earnings Per Share [Text Block] Name Outstanding Recovery, Individual Name Additional paid-in capital Additional Paid in Capital Product and Service [Axis] Product and Service [Axis] Number of contracts Number of Contracts Derivative, Number of Instruments Held Derivative Contract [Domain] Derivative Contract [Domain] Lease cost Variable Lease, Cost Total revenues Revenue from Contract with Customer, Excluding Assessed Tax 2030 Notes Senior Notes Due 2030 [Member] Senior Notes Due 2030 All Individuals All Individuals [Member] Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Transferred at a point in time Transferred at Point in Time [Member] Name Forgone Recovery, Individual Name Total current assets Assets, Current Statistical Measurement [Axis] Statistical Measurement [Axis] Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Deferred compensation plan assets Plan Assets [Member] -- None. No documentation exists for this element. -- Stock repurchase program, authorized amount Share Repurchase Program, Authorized, Amount Proceeds from employee stock purchase plan Proceeds, Issuance of Shares, Share-Based Payment Arrangement, Including Option Exercised Assets: Contract with Customer, Asset, after Allowance for Credit Loss [Abstract] Fixed interest rate Derivative, Fixed Interest Rate Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Foreign currency translation impact Goodwill, Foreign Currency Translation, Gain (Loss) Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Term of contract Derivative, Term of Contract Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Share Repurchase Program [Domain] Share Repurchase Program [Domain] Schedule of Finite-Lived Intangible Assets [Table] Intangible Asset, Finite-Lived [Table] Other comprehensive income (loss), net of tax Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Current liabilities: Liabilities, Current [Abstract] Geographical [Axis] Geographical [Axis] Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance Derivative Instruments, Gain (Loss) [Table Text Block] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Pension plans – net change in deferred actuarial loss Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent Level 1 Fair Value, Inputs, Level 1 [Member] Long-term line of credit Long-Term Line of Credit Diluted (in dollars per share) Diluted income per share (in dollars per share) Earnings Per Share, Diluted Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Fees receivable, net of allowances of $5,000 and $8,500, respectively Accounts Receivable, after Allowance for Credit Loss, Current Title of 12(b) Security Title of 12(b) Security Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] AOCI Attributable to Parent, Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Treasury stock, common shares (in shares) Treasury Stock, Common, Shares Earnings Per Share [Abstract] Earnings Per Share [Abstract] Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] Consolidation Items [Domain] Consolidation Items [Domain] Gross contribution Gross Profit Cash and Cash Equivalents [Line Items] Cash and Cash Equivalents [Line Items] Number of shares repurchased (in shares) Treasury Stock, Shares, Acquired 2027 Finite-Lived Intangible Asset, Expected Amortization, Year Two Award Timing Disclosures [Line Items] Principal amount outstanding Long-Term Debt, Gross Intangible assets fully amortized Finite Lived Intangible Assets, Fully Amortized Intangibles Finite Lived Intangible Assets, Fully Amortized Intangibles Consulting Consulting Consulting [Member] -- None. No documentation exists for this element. -- Measurement Frequency [Domain] Measurement Frequency [Domain] Renewal term (in years) Lessee, Operating Lease, Renewal Term Equity Equity [Text Block] Net income Net income Net income used for calculating basic and diluted income per share Net Income (Loss) Attributable to Parent Gain on event cancellation insurance claims Gain on event cancellation insurance claims Insured Event, Gain (Loss) Intersegment Eliminations Intersegment Eliminations [Member] Expiration Date Trading Arrangement Expiration Date 2030 Finite-Lived Intangible Asset, Expected Amortization, Year Five Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Axis] Net income per share: Net Income Per Share, Basic And Diluted [Abstract] Net Income Per Share, Basic And Diluted Property, equipment and leasehold improvements, net Property, Plant and Equipment, Net Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Purchases of treasury stock Cash paid for repurchased shares Payments for Repurchase of Common Stock Adoption Date Trading Arrangement Adoption Date Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Fees receivable, net Increase (Decrease) in Accounts Receivable Entity Current Reporting Status Entity Current Reporting Status Derivative [Line Items] Derivative [Line Items] Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Customer Relationships Customer Relationships [Member] Operating income Operating Income (Loss) Accumulated earnings Retained Earnings (Accumulated Deficit) Schedule Of Share Repurchase Activity Class of Treasury Stock [Table Text Block] Schedule Of Stock-based Compensation Expense By Award Type Share-Based Payment Arrangement, Cost by Plan [Table Text Block] Financial Instrument [Axis] Financial Instrument [Axis] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Executive Category: Executive Category [Axis] Foreign currency forwards Foreign currency forward contracts Foreign Exchange Forward [Member] Transferred over time Transferred over Time [Member] Current Fiscal Year End Date Current Fiscal Year End Date Interest Rate Swaps Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member] Treasury stock, average price paid per share (in dollars per share) Treasury Stock Average Price Paid Per Share Treasury Stock Average Price Paid Per Share. Cost of services and product development - unallocated Other Cost of Operating Revenue Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Number of shares available for grant (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant Other (expense) income, net Other Nonoperating Income (Expense) Statement [Table] Statement [Table] Deferred taxes Deferred Income Tax Expense (Benefit) Adjustments to reconcile net income to cash provided by operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Financing activities: Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Common stock equivalents Common Stock Equivalents [Member] -- None. No documentation exists for this element. -- Gross cost, beginning balance Finite-Lived Intangible Assets, Excluding Foreign Currency Translation, Gross Finite-Lived Intangible Assets, Excluding Foreign Currency Translation, Gross Total contract liabilities Contract with Customer, Liability Schedule of Assets and Liabilities Measured to Fair Value on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Timing of Transfer of Good or Service [Domain] Timing of Transfer of Good or Service [Domain] Business and Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Unrecognized tax benefits Unrecognized Tax Benefits Antidilutive securities excluded from computation of (loss) income per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Weighted average shares outstanding: Weighted Average Number of Shares Outstanding, Diluted [Abstract] All Adjustments to Compensation All Adjustments to Compensation [Member] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Accounts payable and accrued liabilities Accounts Payable and Accrued Liabilities, Current Amendment Flag Amendment Flag Deferred compensation plan liabilities Plan Liabilities [Member] -- None. No documentation exists for this element. -- Treasury stock, at cost, 90,689,017 and 86,222,214 common shares, respectively Treasury Stock, Common, Value Less: deferred financing fees Debt Issuance Costs, Line of Credit Arrangements, Net Leases Lessee, Operating Leases [Text Block] Termination Date Trading Arrangement Termination Date Cash used in financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Measure: Measure [Axis] Contract assets recorded in Prepaid expenses and other current assets Contract with Customer, Asset, before Allowance for Credit Loss Numerator: Numerator: [Abstract] -- None. No documentation exists for this element. -- Basic (in shares) Weighted average number of common shares used in the calculation of basic income per share (in shares) Weighted Average Number of Shares Outstanding, Basic Stock repurchase program, remaining authorized repurchase amount Share Repurchase Program, Remaining Authorized, Amount Cost of services and product development Cost of Product and Service Sold Schedule Of Basic And Diluted Earnings Per Share Calculations Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Segment Reporting [Abstract] Segment Reporting [Abstract] Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Debt Disclosure [Abstract] Debt Disclosure [Abstract] Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount United States and Canada United States And Canada [Member] -- None. No documentation exists for this element. -- Amortization and write-off of deferred financing fees Amortization of Debt Issuance Costs Entity Tax Identification Number Entity Tax Identification Number Costs and expenses: Costs and Expenses [Abstract] Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Common stock, par value (in dollars per share) 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 Goodwill and Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Use of estimates Use of Estimates, Policy [Policy Text Block] Foreign currency translation impact Finite-Lived Intangible Assets, Foreign Currency Translation Gain (Loss) Schedule of Changes to the Carrying Amount of Goodwill by Reporting Unit Schedule of Goodwill [Table Text Block] Interest expense, net Interest Expense, Nonoperating Trading Arrangement: Trading Arrangement [Axis] Total Shareholder Return Amount Total Shareholder Return Amount Insider Trading Arrangements [Line Items] Security Exchange Name Security Exchange Name Retirement Eligible Employees Equity Award Retirement Eligible Employees Equity Award [Member] -- None. No documentation exists for this element. -- Other Product and Service, Other [Member] Total Liabilities Liabilities Line of credit facility, commitment fee percentage Line of Credit Facility, Commitment Fee Percentage Other expense (income), net Other Nonoperating Income (Expense) [Member] Line of credit facility, maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Acquisition and integration charges Acquisition and integration charges Business Combination, Acquisition and Integration Related Costs Business Combination, Acquisition and Integration Related Costs Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Interest expenses and other, net Interest And Other Nonoperating Income (Expense) Interest And Other Nonoperating Income (Expense) Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Issuances under stock plans Shares Granted, Value, Share-Based Payment Arrangement, after Forfeiture Reduction in the carrying amount of operating lease right-of-use assets Operating Lease, Right-Of-Use Asset, Reduction In Carrying Amount Operating Lease, Right-Of-Use Asset, Reduction In Carrying Amount Statement [Line Items] Statement [Line Items] Consolidation Items [Axis] Consolidation Items [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Cash and cash equivalents Cash and Cash Equivalent Common Stock Common Stock [Member] Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Non-NEOs Non-NEOs [Member]