0000001 - Document - Cover link:presentationLink link:calculationLink link:definitionLink 9952151 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS link:presentationLink link:calculationLink link:definitionLink 9952152 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) link:presentationLink link:calculationLink link:definitionLink 9952153 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) link:presentationLink link:calculationLink link:definitionLink 9952154 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) link:presentationLink link:calculationLink link:definitionLink 9952155 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (UNAUDITED) link:presentationLink link:calculationLink link:definitionLink 9952156 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) link:presentationLink link:calculationLink link:definitionLink 9952157 - Disclosure - Basis of presentation link:presentationLink link:calculationLink link:definitionLink 9952158 - Disclosure - Summary of significant accounting policies link:presentationLink link:calculationLink link:definitionLink 9952159 - Disclosure - Revenue link:presentationLink link:calculationLink link:definitionLink 9952160 - Disclosure - Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) link:presentationLink link:calculationLink link:definitionLink 9952161 - Disclosure - Goodwill link:presentationLink link:calculationLink link:definitionLink 9952162 - Disclosure - Intangible assets link:presentationLink link:calculationLink link:definitionLink 9952163 - Disclosure - Fair value measurements link:presentationLink link:calculationLink link:definitionLink 9952164 - Disclosure - Restructuring link:presentationLink link:calculationLink link:definitionLink 9952165 - Disclosure - Operating leases link:presentationLink link:calculationLink link:definitionLink 9952166 - Disclosure - Bank credit lines, loan facilities and notes link:presentationLink link:calculationLink link:definitionLink 9952167 - Disclosure - Income taxes link:presentationLink link:calculationLink link:definitionLink 9952168 - Disclosure - Net income per ordinary share link:presentationLink link:calculationLink link:definitionLink 9952169 - Disclosure - Share-based awards link:presentationLink link:calculationLink link:definitionLink 9952170 - Disclosure - Share capital link:presentationLink link:calculationLink link:definitionLink 9952171 - Disclosure - Business Segment and Geographical Information link:presentationLink link:calculationLink link:definitionLink 9952172 - Disclosure - Commitments and contingencies link:presentationLink link:calculationLink link:definitionLink 9952173 - Disclosure - Subsequent events link:presentationLink link:calculationLink link:definitionLink 9955511 - Disclosure - Summary of significant accounting policies (Policies) link:presentationLink link:calculationLink link:definitionLink 9955512 - Disclosure - Summary of significant accounting policies (Tables) link:presentationLink link:calculationLink link:definitionLink 9955513 - Disclosure - Revenue (Tables) link:presentationLink link:calculationLink link:definitionLink 9955514 - Disclosure - Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) (Tables) link:presentationLink link:calculationLink link:definitionLink 9955515 - Disclosure - Goodwill (Tables) link:presentationLink link:calculationLink link:definitionLink 9955516 - Disclosure - Intangible assets (Tables) link:presentationLink link:calculationLink link:definitionLink 9955517 - Disclosure - Fair value measurements (Tables) link:presentationLink link:calculationLink link:definitionLink 9955518 - Disclosure - Restructuring (Tables) link:presentationLink link:calculationLink link:definitionLink 9955519 - Disclosure - Operating leases (Tables) link:presentationLink link:calculationLink link:definitionLink 9955520 - Disclosure - Bank credit lines, loan facilities and notes (Tables) link:presentationLink link:calculationLink link:definitionLink 9955521 - Disclosure - Income taxes (Tables) link:presentationLink link:calculationLink link:definitionLink 9955522 - Disclosure - Net income per ordinary share (Tables) link:presentationLink link:calculationLink link:definitionLink 9955523 - Disclosure - Share-based awards (Tables) link:presentationLink link:calculationLink link:definitionLink 9955524 - Disclosure - Share capital (Tables) link:presentationLink link:calculationLink link:definitionLink 9955525 - Disclosure - Business Segment and Geographical Information (Tables) link:presentationLink link:calculationLink link:definitionLink 9955526 - Disclosure - Summary of significant accounting policies - Schedule of Finite-Lived Intangible Assets (Details) link:presentationLink link:calculationLink link:definitionLink 9955527 - Disclosure - Revenue (Details) link:presentationLink link:calculationLink link:definitionLink 9955528 - Disclosure - Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) - Schedule of Accounts Receivables and Unbilled Revenue (Details) link:presentationLink link:calculationLink link:definitionLink 9955529 - Disclosure - Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) - Schedule of Unbilled Services and Unearned Revenue or Payments on Account (Details) link:presentationLink link:calculationLink link:definitionLink 9955530 - Disclosure - Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955530 - Disclosure - Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955531 - Disclosure - Goodwill - Schedule of Goodwill (Details) link:presentationLink link:calculationLink link:definitionLink 9955532 - Disclosure - Goodwill - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955533 - Disclosure - Intangible assets - Schedule of Finite-Lived Intangible Assets (Details) link:presentationLink link:calculationLink link:definitionLink 9955534 - Disclosure - Intangible assets - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955535 - Disclosure - Fair value measurements - Schedule of Measurement of Fair Value of Major Asset and Liability classed (Details) link:presentationLink link:calculationLink link:definitionLink 9955536 - Disclosure - Fair value measurements - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955537 - Disclosure - Restructuring - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955538 - Disclosure - Restructuring - Schedule of Restructuring Charges (Details) link:presentationLink link:calculationLink link:definitionLink 9955539 - Disclosure - Restructuring - Schedule of Details of Movement in Restructuring Charges (Details) link:presentationLink link:calculationLink link:definitionLink 9955540 - Disclosure - Operating leases - Schedule of Lease Costs (Details) link:presentationLink link:calculationLink link:definitionLink 9955541 - Disclosure - Operating leases - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955542 - Disclosure - Operating leases - Schedule of Operating Lease Maturity (Details) link:presentationLink link:calculationLink link:definitionLink 9955542 - Disclosure - Operating leases - Schedule of Operating Lease Maturity (Details) link:presentationLink link:calculationLink link:definitionLink 9955543 - Disclosure - Bank credit lines, loan facilities and notes - Schedule of Long-term Debt Instruments (Details) link:presentationLink link:calculationLink link:definitionLink 9955544 - Disclosure - Bank credit lines, loan facilities and notes - Schedule of Contractual Maturities of Debt (Details) link:presentationLink link:calculationLink link:definitionLink 9955545 - Disclosure - Bank credit lines, loan facilities and notes - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955546 - Disclosure - Bank credit lines, loan facilities and notes - Schedule of Principal Payments on Debt Instruments (Details) link:presentationLink link:calculationLink link:definitionLink 9955547 - Disclosure - Bank credit lines, loan facilities and notes - Schedule of Movement on Debt Instrument (Details) link:presentationLink link:calculationLink link:definitionLink 9955548 - Disclosure - Income taxes - Schedule of Components of Tax (Details) link:presentationLink link:calculationLink link:definitionLink 9955549 - Disclosure - Income taxes - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955550 - Disclosure - Income taxes - Schedule of Reconciliation of Beginning and Ending Amount of Total Unrecognized Tax Benefits (Details) link:presentationLink link:calculationLink link:definitionLink 9955551 - Disclosure - Net income per ordinary share - Schedule of Reconciliation of Number of Shares Used in Computation of Basic and Diluted Net Income Per Ordinary Share (Details) link:presentationLink link:calculationLink link:definitionLink 9955552 - Disclosure - Net income per ordinary share - Schedule of Reconciliation of Net Income Attributable to the Group (Details) link:presentationLink link:calculationLink link:definitionLink 9955553 - Disclosure - Share-based awards - Schedule of Stock Option Activity (Details) link:presentationLink link:calculationLink link:definitionLink 9955554 - Disclosure - Share-based awards - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955555 - Disclosure - Share-based awards - Schedule of Weighted Average Fair Values and Assumptions Used (Details) link:presentationLink link:calculationLink link:definitionLink 9955556 - Disclosure - Share-based awards - Schedule of RSU and PSU Activity (Details) link:presentationLink link:calculationLink link:definitionLink 9955557 - Disclosure - Share-based awards - Schedule of Non-Cash Stock Compensation Expense (Details) link:presentationLink link:calculationLink link:definitionLink 9955558 - Disclosure - Share capital - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955559 - Disclosure - Share capital - Schedule of Shares Redeemed Under Buyback Program (Details) link:presentationLink link:calculationLink link:definitionLink 9955560 - Disclosure - Business Segment and Geographical Information - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955561 - Disclosure - Business Segment and Geographical Information - Schedule of Distribution of Revenue by Geographical Area (Details) link:presentationLink link:calculationLink link:definitionLink 9955562 - Disclosure - Business Segment and Geographical Information - Schedule of Distribution of Income from Operations by Geographical Area (Details) link:presentationLink link:calculationLink link:definitionLink 9955563 - Disclosure - Business Segment and Geographical Information - Schedule of Distribution of Depreciation and Amortization by Geographical Area (Details) link:presentationLink link:calculationLink link:definitionLink 9955564 - Disclosure - Commitments and Contingencies (Details) link:presentationLink link:calculationLink link:definitionLink