0001001 - Document - Cover link:presentationLink link:calculationLink link:definitionLink 1001002 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS link:presentationLink link:calculationLink link:definitionLink 1002003 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) link:presentationLink link:calculationLink link:definitionLink 1003004 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) link:presentationLink link:calculationLink link:definitionLink 1004005 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) link:presentationLink link:calculationLink link:definitionLink 1005006 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (UNAUDITED) link:presentationLink link:calculationLink link:definitionLink 1006007 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) link:presentationLink link:calculationLink link:definitionLink 2101101 - Disclosure - Basis of presentation link:presentationLink link:calculationLink link:definitionLink 2402401 - Disclosure - Basis of presentation (Details) link:presentationLink link:calculationLink link:definitionLink 2103102 - Disclosure - Significant accounting policies link:presentationLink link:calculationLink link:definitionLink 2204201 - Disclosure - Significant accounting policies (Policies) link:presentationLink link:calculationLink link:definitionLink 2105103 - Disclosure - Revenue link:presentationLink link:calculationLink link:definitionLink 2306301 - Disclosure - Revenue (Tables) link:presentationLink link:calculationLink link:definitionLink 2407402 - Disclosure - Revenue (Details) link:presentationLink link:calculationLink link:definitionLink 2108104 - Disclosure - Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) link:presentationLink link:calculationLink link:definitionLink 2309302 - Disclosure - Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) (Tables) link:presentationLink link:calculationLink link:definitionLink 2410403 - 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 2411404 - 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 2412405 - Disclosure - Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 2412405 - Disclosure - Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 2113105 - Disclosure - Goodwill link:presentationLink link:calculationLink link:definitionLink 2314303 - Disclosure - Goodwill (Tables) link:presentationLink link:calculationLink link:definitionLink 2415406 - Disclosure - Goodwill - Schedule of Goodwill (Details) link:presentationLink link:calculationLink link:definitionLink 2416407 - Disclosure - Goodwill - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 2117106 - Disclosure - Intangible assets link:presentationLink link:calculationLink link:definitionLink 2318304 - Disclosure - Intangible assets (Tables) link:presentationLink link:calculationLink link:definitionLink 2419408 - Disclosure - Intangible assets (Details) link:presentationLink link:calculationLink link:definitionLink 2120107 - Disclosure - Business combinations link:presentationLink link:calculationLink link:definitionLink 2321305 - Disclosure - Business combinations (Tables) link:presentationLink link:calculationLink link:definitionLink 2422409 - Disclosure - Business combinations - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 2423410 - Disclosure - Business combinations - Schedule of Fair Value of PRA Health Sciences Inc Acquisition Consideration (Details) link:presentationLink link:calculationLink link:definitionLink 2424411 - Disclosure - Business combinations - Schedule of PRA Health Sciences Inc Acquisition (Details) link:presentationLink link:calculationLink link:definitionLink 2425412 - Disclosure - Business combinations - Schedule of Fair Value of Intangible Assets PRA Health Sciences Inc Acquisition (Details) link:presentationLink link:calculationLink link:definitionLink 2426413 - Disclosure - Schedule of Measurement Period Adjustments of PRA Health Sciences Inc Acquisition (Details) link:presentationLink link:calculationLink link:definitionLink 2427414 - Disclosure - Business combinations - Schedule of Proforma Information of PRA Health Sciences Inc Acquisition (Details) link:presentationLink link:calculationLink link:definitionLink 2128108 - Disclosure - Equity method investments link:presentationLink link:calculationLink link:definitionLink 2329306 - Disclosure - Equity method investments (Tables) link:presentationLink link:calculationLink link:definitionLink 2430415 - Disclosure - Equity method investments - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 2431416 - Disclosure - Equity method investments - Summary of Equity Method Investments (Details) link:presentationLink link:calculationLink link:definitionLink 2132109 - Disclosure - Fair value measurements link:presentationLink link:calculationLink link:definitionLink 2433417 - Disclosure - Fair value measurements (Details) link:presentationLink link:calculationLink link:definitionLink 2134110 - Disclosure - Restructuring link:presentationLink link:calculationLink link:definitionLink 2335307 - Disclosure - Restructuring (Tables) link:presentationLink link:calculationLink link:definitionLink 2436418 - Disclosure - Restructuring - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 2437419 - Disclosure - Restructuring - Summary of Restructuring Charges (Details) link:presentationLink link:calculationLink link:definitionLink 2438420 - Disclosure - Restructuring - Summary of Details of Movement in Restructuring Charges (Details) link:presentationLink link:calculationLink link:definitionLink 2139111 - Disclosure - Operating leases link:presentationLink link:calculationLink link:definitionLink 2340308 - Disclosure - Operating leases (Tables) link:presentationLink link:calculationLink link:definitionLink 2441421 - Disclosure - Operating leases - Schedule of Lease Costs (Details) link:presentationLink link:calculationLink link:definitionLink 2442422 - Disclosure - Operating leases - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 2443423 - Disclosure - Operating leases - Schedule of Operating Lease Maturity (Details) link:presentationLink link:calculationLink link:definitionLink 2443423 - Disclosure - Operating leases - Schedule of Operating Lease Maturity (Details) link:presentationLink link:calculationLink link:definitionLink 2144112 - Disclosure - Bank credit lines and loan facilities link:presentationLink link:calculationLink link:definitionLink 2345309 - Disclosure - Bank credit lines and loan facilities (Tables) link:presentationLink link:calculationLink link:definitionLink 2446424 - Disclosure - Bank credit lines and loan facilities - Schedule of Outstanding Debt (Details) link:presentationLink link:calculationLink link:definitionLink 2447425 - Disclosure - Bank credit lines and loan facilities - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 2448426 - Disclosure - Bank credit lines and loan facilities - Schedule of Contractual Maturities of Debt (Details) link:presentationLink link:calculationLink link:definitionLink 2149113 - Disclosure - Income taxes link:presentationLink link:calculationLink link:definitionLink 2350310 - Disclosure - Income taxes (Tables) link:presentationLink link:calculationLink link:definitionLink 2451427 - Disclosure - Income taxes - Schedule of Components of Income Tax Expense (Details) link:presentationLink link:calculationLink link:definitionLink 2452428 - Disclosure - Income taxes - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 2153114 - Disclosure - Net income per ordinary share link:presentationLink link:calculationLink link:definitionLink 2354311 - Disclosure - Net income per ordinary share (Tables) link:presentationLink link:calculationLink link:definitionLink 2455429 - 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 2456430 - Disclosure - Net income per ordinary share - Schedule of Reconciliation of Net Income Attributable to the Group (Details) link:presentationLink link:calculationLink link:definitionLink 2157115 - Disclosure - Share-based awards link:presentationLink link:calculationLink link:definitionLink 2358312 - Disclosure - Share-based awards (Tables) link:presentationLink link:calculationLink link:definitionLink 2459431 - Disclosure - Share-based awards - Summary of Stock Option Activity (Details) link:presentationLink link:calculationLink link:definitionLink 2460432 - Disclosure - Share-based awards - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 2461433 - Disclosure - Share-based awards - Schedule of Weighted Average Fair Values and Assumptions Used (Details) link:presentationLink link:calculationLink link:definitionLink 2462434 - Disclosure - Share-based awards - Summary of RSU and PSU Activity (Details) link:presentationLink link:calculationLink link:definitionLink 2463435 - Disclosure - Share-based awards - Schedule of Non-cash Stock Compensation Expense (Details) link:presentationLink link:calculationLink link:definitionLink 2164116 - Disclosure - Share capital link:presentationLink link:calculationLink link:definitionLink 2465436 - Disclosure - Share capital (Details) link:presentationLink link:calculationLink link:definitionLink 2166117 - Disclosure - Business Segment and Geographical Information link:presentationLink link:calculationLink link:definitionLink 2367313 - Disclosure - Business Segment and Geographical Information (Tables) link:presentationLink link:calculationLink link:definitionLink 2468437 - Disclosure - Business Segment and Geographical Information - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 2469438 - Disclosure - Business Segment and Geographical Information - Schedule of Distribution of Revenue by Geographical Area (Details) link:presentationLink link:calculationLink link:definitionLink 2470439 - Disclosure - Business Segment and Geographical Information - Schedule of Distribution of Income from Operations by Geographical Area (Details) link:presentationLink link:calculationLink link:definitionLink 2471440 - Disclosure - Business Segment and Geographical Information - Schedule of Distribution of Depreciation and Amortization by Geographical Area (Details) link:presentationLink link:calculationLink link:definitionLink