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measurements Fair Value Disclosures [Text Block] Number of operating segments Number of Operating Segments Revenue benchmark Revenue Benchmark [Member] 2028 and thereafter Long-Term Debt, Maturity, Year Four And Thereafter Long-Term Debt, Maturity, Year Four And Thereafter Personnel related liabilities Personnel Related Liabilities [Member] Personnel Related Liabilities Schedule of Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Equity [Abstract] Equity [Abstract] Weighted average remaining lease term Operating Lease, Weighted Average Remaining Lease Term Revenue Revenue from Contract with Customer, Excluding Assessed Tax Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Facility liability Facility Liability [Member] Facility Liability Amendment Flag Amendment Flag Intangible assets Intangible Assets Disclosure [Text Block] 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] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Payments to acquire businesses, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Weighted average discount rate Operating Lease, Weighted Average Discount Rate, Percent Credit Facility [Domain] Credit Facility [Domain] Basis spread on variable rate (in percent) Debt Instrument, Basis Spread on Variable Rate Total long-term debt, net Long-Term Debt, Excluding Current Maturities Goodwill Goodwill Disclosure [Text Block] Buyback Program Buyback Program [Member] Buyback Program [Member] Diluted (in shares) Weighted average number of ordinary shares outstanding for diluted net income per ordinary share (in shares) Weighted Average Number of Shares Outstanding, Diluted Derivative Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Derivative Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Schedule of accounts receivables and unbilled revenue, and unbilled services and unearned revenue Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] Additional ordinary shares which have been reserved for issuance (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized Revenue Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) Revenue from Contract with Customer [Text Block] Purchase of property, plant and equipment Payments to Acquire Property, Plant, and Equipment 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] Additional paid-in capital Additional Paid in Capital, Common Stock Additional Paid-in Capital Additional Paid-in Capital [Member] Gain / (loss) on cash flow hedge Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax Balance Sheet Location [Axis] Balance Sheet Location [Axis] Total Assets Assets Share of losses from equity method investments Loss on equity method investments Income (Loss) from Equity Method Investments Share Repurchase Program Share Repurchase Program [Axis] Cover [Abstract] Subsequent Events Subsequent Events [Text Block] Shared based compensation expense APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Amortization of financing costs and debt discount Amortization of Debt Issuance Costs U.S. UNITED STATES Restructuring and Related Activities [Abstract] Restructuring and Related Activities [Abstract] Non-current other liabilities Other Liabilities, Noncurrent Shares vested (in USD per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Total future minimum lease payments Lessee, Operating Lease, Liability, to be Paid Revenue, remaining performance obligation Revenue, Remaining Performance Obligation, Amount Business Segment and Geographical Information Segment Reporting Disclosure [Text Block] Net increase / (decrease) in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Variable Rate Component [Domain] Variable Rate Component [Domain] Variable Rate Component [Domain] Senior Secured Term Loan Secured Debt [Member] 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 Equity Component [Domain] Equity Component [Domain] Debt Instrument [Line Items] Debt Instrument [Line Items] 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 Concentration Risk Type [Domain] Concentration Risk Type [Domain] Income from operations Income from operations Operating Income (Loss) Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Schedule of Indefinite-Lived Intangible Assets [Table] Schedule of Indefinite-Lived Intangible Assets [Table] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Statement [Line Items] Statement [Line Items] Other comprehensive income, net of tax: Other Comprehensive Income (Loss), Net of Tax [Abstract] Change in unbilled services (unbilled revenue) Increase 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 Long-term Debt Instruments Schedule of Debt [Table Text Block] Customer relationships Customer Relationships [Member] Type of Restructuring [Domain] Type of Restructuring [Domain] Other Liabilities