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Liabilities, Noncurrent Patient database Database Rights [Member] Direct costs Cost of Goods and Service, Excluding Depreciation, Depletion, and Amortization Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Commitments and contingencies Commitments and Contingencies Compensation Related Costs Share Based Payments Disclosure [Line Items] Compensation Related Costs Share Based Payments Disclosure [Line Items] Compensation Related Costs Share Based Payments Disclosure [Line Items] 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] Year 2 Lessee, Operating Lease, Liability, to be Paid, Year Two 2026 Long-Term Debt, Maturity, Year One Share-based awards Share-Based Payment Arrangement [Text Block] Schedule of Distribution of Revenue by Geographical Area Revenue from External Customers by Geographic Areas [Table Text Block] Debt Instrument [Axis] Debt Instrument [Axis] Summary of Stock Option Activity Share-Based Payment Arrangement, Option, Activity [Table Text Block] Total Share-Based Payment Arrangement, Expense Net income Net Income (Loss) Attributable to Parent Granted (in USD per share) Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period Business Acquisition [Axis] Business Acquisition [Axis] Schedule of Finite-Lived Intangible Assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Weighted Average Remaining Contractual Life Share-based Compensation Arrangement by Share-based Payment Award, Options, Weighted Average Remaining Contractual Term [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Options, Weighted Average Remaining Contractual Term [Abstract] Revenue Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) Revenue from Contract with Customer [Text Block] Document Fiscal Year Focus Document Fiscal Year Focus Income Statement [Abstract] Income Statement [Abstract] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Effect of exchange rate movements on cash Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Continuing Operations Total assets Total assets Assets, Fair Value Disclosure Weighted average remaining lease term Operating Lease, Weighted Average Remaining Lease Term Document Period End Date Document Period End Date Other non-cash items Other Noncash Income (Expense) Base rate Base Rate [Member] Senior Secured Notes (the "2027 Notes")* Senior Secured Notes Due May 2027 [Member] Senior Secured Notes Due May 2027 Total future minimum lease payments Lessee, Operating Lease, Liability, to be Paid Outstanding at beginning of period (in shares) Outstanding at end of period (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number Variable Rate Component [Domain] Variable Rate Component [Domain] Variable Rate Component [Domain] Goodwill at fair value Goodwill, Fair Value Disclosure Year 3 Lessee, Operating Lease, Liability, to be Paid, Year Three Percentage change in unearned revenue (payments on account) Increase (Decrease) In Contract With Customer, Liability, Gross, Current, Percent Increase (Decrease) In Contract with Customer, Liability, Gross, Current, Percent Prepayments and other current assets Prepaid Expense and Other Assets, Current Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Customer [Domain] Customer [Domain] Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Retained Earnings Retained Earnings [Member] Amortization of financing costs and debt discount Amortization of Debt Issuance Costs Basic (in shares) Weighted average number of ordinary shares outstanding for basic net income per ordinary share (in shares) Weighted Average Number of Shares Outstanding, Basic Schedule of Segment Reporting Information, by Segment [Table] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Change in unbilled services (unbilled revenue) Increase (Decrease) In Contract With Customer, Asset, Gross, Current Increase (Decrease) In Contract With Customer, Asset, Gross, Current Schedule of Components of Income Tax Expense Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Restructuring reserve Opening provision Closing provision Restructuring Reserve Revenue, remaining performance obligation Revenue, Remaining Performance Obligation, Amount Income Statement Location [Domain] Statement of Income Location, Balance [Domain] Costs and expenses: Cost of Revenue [Abstract] Other Liabilities