Statement of Cash Flows [Abstract]
Cash flows from operating activities:
Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract]
Net income
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest
Adjustments to reconcile net income to net cash provided by operating activities:
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Loss on disposal of property, plant and equipment
Gain (Loss) on Disposition of Property Plant Equipment
Depreciation expense
Depreciation
Reduction in carrying value of operating right-of-use assets
Operating Lease, Right-of-Use Asset, Amortization Expense
Operating Lease, Right-of-Use Asset, Amortization Expense
Amortization of intangibles
Amortization of Intangible Assets
Amortization of government grants
Recovery of Amortization of Government Grants
Amortization of Government Grants.
Interest on short term investments
Accrued Interest On Short Term Bank Deposits
Accrued Interest On Short Term Bank Deposits
Interest on non-current operating lease liability
Accrued Interest On Operating Lease Liability
Accrued Interest On Operating Lease Liability
Realized gain on sale of short term investments
Gain (Loss) on Sale of Investments
Loss/(gain) on re-measurement of financial assets
Increase (Decrease) in Equity Securities, FV-NI
Stock compensation expense
Share-based Payment Arrangement, Noncash Expense
Amortization of interest rate hedge
Amortization of Deferred Hedge Gains
Amortization of financing costs
Amortization of Debt Issuance Costs
Deferred taxes
Deferred Income Taxes and Tax Credits
Changes in assets and liabilities:
Increase (Decrease) in Operating Capital [Abstract]
Decrease in accounts receivable
Increase (Decrease) in Accounts Receivable
Increase in unbilled revenue
Increase (Decrease) in Contract with Customer, Asset
Decrease in other receivables
Increase (Decrease) in Other Receivables
Increase in prepayments and other current assets
Increase (Decrease) in Prepaid Expense and Other Assets
Decrease/(increase) in other non-current assets
Increase (Decrease) in Other Noncurrent Assets
Increase in unearned revenue
Increase (Decrease) in Contract with Customer, Liability
Increase in other current liabilities
Increase (Decrease) in Other Current Liabilities
Decrease in operating lease liabilities
Increase (Decrease) In Operating Lease Liabilities
Increase (Decrease) in Operating Lease Liabilities
Increase/(decrease) in other non-current liabilities
Increase (Decrease) in Other Noncurrent Liabilities
Increase in income taxes payable
Increase (Decrease) in Income Taxes Payable
(Decrease)/increase in accounts payable
Increase (Decrease) in Accounts Payable
Net cash provided by operating activities
Net Cash Provided by (Used in) Operating Activities
Cash flows from investing activities:
Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract]
Purchase of property, plant and equipment
Payments to Acquire Property, Plant, and Equipment
Purchase of subsidiary undertakings
Payments to Acquire Businesses, Gross
Cash acquired with subsidiary undertaking
Cash Acquired from Acquisition
Purchase of available for sale investments
Payments to Acquire Debt Securities, Available-for-sale
Sale of available for sale investments
Proceeds from Sale of Debt Securities, Available-for-sale
Purchase of investments in equity - long term
Payments to Acquire Long-term Investments
Net cash used in investing activities
Net Cash Provided by (Used in) Investing Activities
Cash flows from financing activities:
Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract]
Proceeds from exercise of equity compensation
Proceeds from Stock Options Exercised
Share issue costs
Payments of Stock Issuance Costs
Repurchase of ordinary shares
Payments for Repurchase of Common Stock
Share repurchase costs
Payments for Share Repurchase Costs
Payments for Share Repurchase Costs
Net cash used in financing activities
Net Cash Provided by (Used in) Financing Activities
Effect of exchange rate movements on cash
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents
Net (decrease)/increase in cash and cash equivalents
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect
Cash and cash equivalents at beginning of period
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents
Cash and cash equivalents at end of period
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill
Goodwill Disclosure [Text Block]
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment [Table]
Schedule of Segment Reporting Information, by Segment [Table]
Geographical [Axis]
Geographical [Axis]
Geographical [Domain]
Geographical [Domain]
Ireland
IRELAND
Rest of Europe
Rest Of Europe [Member]
Rest Of Europe [Member]
U.S.
UNITED STATES
Rest of World
Rest of World [Member]
Rest of World [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information [Line Items]
Revenue
Revenue from Contract with Customer, Excluding Assessed Tax
Income Tax Disclosure [Abstract]
Liability for unrecognized tax benefit
Unrecognized Tax Benefits
Items generating unrecognized tax benefits
Unrecognized Tax Benefits, Current Year Tax Positions
Unrecognized Tax Benefits, Current Year Tax Positions
Interest and related penalties
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued
Income Statement [Abstract]
Costs and expenses:
Cost of Revenue [Abstract]
Direct costs
Cost of Goods and Services Sold
Selling, general and administrative expense
Selling, General and Administrative Expense
Depreciation and amortization
Depreciation, Depletion and Amortization, Nonproduction
Total costs and expenses
Costs and Expenses
Income from operations
Operating Income (Loss)
Interest income
Investment Income, Interest
Interest expense
Interest Expense, Debt
Provision for income taxes
Income Tax Expense (Benefit)
Net income
Net income attributable to noncontrolling interest
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest
Net income attributable to the Group
Net Income (Loss) Attributable to Parent
Net income per Ordinary Share attributable to the Group (note 10):
Earnings Per Share [Abstract]
Basic (USD per share)
Earnings Per Share, Basic
Diluted (USD per share)
Earnings Per Share, Diluted
Weighted average number of Ordinary Shares outstanding:
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Basic (in shares)
Weighted Average Number of Shares Outstanding, Basic
Diluted (in shares)
Weighted Average Number of Shares Outstanding, Diluted
Accounting Policies [Abstract]
Basis of presentation
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]
Schedule of Earnings Per Share, Basic and Diluted
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Goodwill [Roll Forward]
Goodwill [Roll Forward]
Opening balance
Goodwill
Current period acquisitions (Note 6)
Goodwill, Acquired During Period
Prior period acquisitions
Goodwill, Purchase Accounting Adjustments
Foreign exchange movement
Goodwill, Foreign Currency Translation Gain (Loss)
Closing balance
Share-based Payment Arrangement [Abstract]
Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]
Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]
Award Type [Axis]
Award Type [Axis]
Award Type [Domain]
Award Type [Domain]
Employee Stock Option
Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding Number of Shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at beginning of period (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number
Granted (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross
Exercised (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period
Canceled/expired (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period
Outstanding at end of period (in shares)
Exercisable at end of period (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number
Weighted Average Exercise Price
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding at beginning of period (USD per share)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price
Granted (USD per share)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price
Exercised (USD per share)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price
Canceled/expired (USD per share)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price
Outstanding at end of period (USD per share)
Exercisable at end of period (USD per share)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price
Weighted Average Grant Date Fair Value
Share-based Compensation Arrangement by Share-based Payment Award, Options, Weighted Average Grant Date Fair Value [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Weighted Average Grant Date Fair Value [Abstract]
Outstanding at beginning of period (USD per share)
Share Based Compensation Arrangement by Share Based Payment Award, Options, Weighted Average Grant Date Fair Value
Share Based Compensation Arrangement by Share Based Payment Award, Options, Weighted Average Grant Date Fair Value
Granted (USD per share)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value
Exercised (USD per share)
Share Based Compensation Arrangement By Share Based Payment Award Options Exercised In Period Weighted Average Grant Date Fair Value
Share Based Compensation Arrangement By Share Based Payment Award Options Exercised In Period Weighted Average Grant Date Fair Value
Canceled/expired (USD per share)
Share-based Compensation Arrangement By Share-based Payment Award, Options, Forfeitures And Expirations In Period, Weighted Average Grant Date Fair Value
Share-based Compensation Arrangement By Share-based Payment Award, Options, Forfeitures And Expirations In Period, Weighted Average Grant Date Fair Value
Outstanding at end of period (USD per share)
Exercisable at end of period (USD per share)
Share Based Compensation Arrangement by Share Based Payment Award, Options, Exercisable, Weighted Average Grant Date Fair Value
Share Based Compensation Arrangement by Share Based Payment Award, Options, Exercisable, Weighted Average Grant Date Fair Value
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]
Outstanding at end of period (in years)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term
Exercisable at end of period (in years)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term
Weighted average grant date fair value
Assumptions:
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected volatility
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate
Dividend yield
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate
Risk-free interest rate
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate
Expected life
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term
Leases [Abstract]
Due within 1 year
Lessee, Operating Lease, Liability, Payments, Due Next Rolling Twelve Months
Due between 1 and 5 years
Lessee, Operating Lease, Liability, Payments, Due Between Rolling Year One And Year Five
Lessee, Operating Lease, Liability, Payments, Due Between Rolling Year One and Year Five
Thereafter
Lessee, Operating Lease, Liability, Payments, Due after Rolling Year Five
Total future minimum lease payments
Lessee, Operating Lease, Liability, Payments, Due
Lease imputed interest
Lessee, Operating Lease, Liability, Undiscounted Excess Amount
Operating lease liabilities
Operating Lease, Liability
Schedule of Components of Income Tax Expense
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition [Table]
Schedule of Business Acquisitions, by Acquisition [Table]
Finite-Lived Intangible Assets by Major Class [Axis]
Finite-Lived Intangible Assets by Major Class [Axis]
Finite-Lived Intangible Assets, Major Class Name [Domain]
Finite-Lived Intangible Assets, Major Class Name [Domain]
Customer relationships
Customer Relationships [Member]
Order backlog
Order or Production Backlog [Member]
Patient database
Database Rights [Member]
Business Acquisition [Axis]
Business Acquisition [Axis]
Business Acquisition, Acquiree [Domain]
Business Acquisition, Acquiree [Domain]
Medpass
Medpass Group Limited [Member]
Medpass Group Limited [Member]
Symphony
CRN Holdings LLC, Symphony [Member]
CRN Holdings LLC, Symphony [Member]
MeDiNova
MeDiNova Research [Member]
MeDiNova Research [Member]
MMD
MolecularMD Corp [Member]
MolecularMD Corp [Member]
Business Acquisition [Line Items]
Business Acquisition [Line Items]
Percentage of share capital acquired
Business Acquisition, Percentage of Voting Interests Acquired
Percentage of interest acquired
Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage
Cash & cash equivalents
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents
Property, plant and equipment
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment
Operating right of use assets
Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Operating Lease, Right-Of-Use Asset
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Operating Lease, Right-of-Use Asset
Goodwill
Intangible asset
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles
Accounts receivable
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables
Unbilled revenue
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Unbilled Revenue
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Unbilled Revenue
Prepayments and other current assets
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets
Other receivables
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Other Receivables
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Other Receivables
Deferred tax asset
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets
Accounts payable
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable
Unearned revenue
Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Contract With Customer, Liability, Current
Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Contract With Customer, Liability, Current
Other liabilities
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other
Current lease liabilities
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Operating Lease Liability
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Operating Lease Liability
Non-current lease liabilities
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Operating Lease Liability
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Operating Lease Liability
Non-current deferred tax liability
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities
Net assets acquired
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net
Cash outflows
Working capital adjustment
Business Combination, Consideration Transferred, Working Capital Adjustments
Business Combination, Consideration Transferred, Working Capital Adjustments
Redeemable noncontrolling interest
Business Combination Acquisition Of Less Than 100 Percent Redeemable Noncontrolling Interest Fair Value
Business Combination Acquisition Of Less Than 100 Percent Redeemable Noncontrolling Interest Fair Value
Non-current other liabilities
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other
Contingent consideration
Business Combination, Contingent Consideration, Liability
Total consideration
Business Combination, Consideration Transferred
Goodwill expected to be tax deductible
Business Acquisition, Goodwill, Expected Tax Deductible Amount
Contingent consideration, maximum amount
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High
Restructuring and Related Activities [Abstract]
Details of Movement in Restructuring Provisions Recognized
Schedule of Restructuring Reserve by Type of Cost [Table Text Block]
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue
Disaggregation of Revenue [Table Text Block]
Schedule of Restructuring and Related Costs [Table]
Schedule of Restructuring and Related Costs [Table]
Restructuring Plan [Axis]
Restructuring Plan [Axis]
Restructuring Plan [Domain]
Restructuring Plan [Domain]
Resource Rationalizations 2018
Resource Rationalizations 2018 [Member]
Resource Rationalizations 2018 [Member]
Restructuring Program [Axis]
Restructuring Program [Axis]
Restructuring Program [Axis]
Restructuring Program [Domain]
Restructuring Program [Domain]
Restructuring Program [Domain]
Workforce Reduction
Workforce Reduction [Member]
Workforce Reduction [Member]
Onerous Lease
Onerous Lease [Member]
Onerous Lease [Member]
Balance Sheet Location [Axis]
Balance Sheet Location [Axis]
Balance Sheet Location [Domain]
Balance Sheet Location [Domain]
Other liabilities
Other Current Liabilities [Member]
Non-current other liabilities
Other Noncurrent Liabilities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Cost and Reserve [Line Items]
Restructuring charges
Restructuring Charges
Restructuring reserve, current
Restructuring Reserve, Current
Restructuring reserve, noncurrent
Restructuring Reserve, Noncurrent
Redeemable noncontrolling interests and equity
Redeemable Noncontrolling Interests And Equity [Policy Text Block]
Redeemable Noncontrolling Interests And Equity [Policy Text Block]
New accounting pronouncements
New Accounting Pronouncements, Policy [Policy Text Block]
Options Outstanding Number of Shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Non-vested outstanding at beginning of period (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares
Granted (in shares)
Vested (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares
Forfeited (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares
Non-vested outstanding at end of period (in shares)
Weighted Average Exercise Price
Share Based Compensation Arrangement By Share Based Payment Award Nonvested Options Outstanding Exercise Price Abstract
Share Based Compensation Arrangement By Share Based Payment Award Nonvested Options Outstanding Exercise Price Abstract
Non-vested outstanding at beginning of period (USD per share)
Share Based Compensation Arrangement by Share Based Payment Award, Nonvested Options, Outstanding Weighted Average Exercise Price
Share Based Compensation Arrangement by Share Based Payment Award, Nonvested Options, Outstanding Weighted Average Exercise Price
Granted (USD per share)
Share Based Compensation Arrangement by Share Based Payment Award, Nonvested Options, Granted in Period Weighted Average Exercise Price
Share Based Compensation Arrangement by Share Based Payment Award, Nonvested Options, Granted in Period Weighted Average Exercise Price
Vested (USD per share)
Share Based Compensation Arrangement by Share Based Payment Award, Nonvested Options, Vested in Period Weighted Average Exercise Price
Share Based Compensation Arrangement by Share Based Payment Award, Nonvested Options, Vested in Period Weighted Average Exercise Price
Forfeited (USD per share)
Share Based Compensation Arrangement by Share Based Payment Award, Nonvested Options, Forfeited in Period Weighted Average Exercise Price
Share Based Compensation Arrangement by Share Based Payment Award, Nonvested Options, Forfeited in Period Weighted Average Exercise Price
Non-vested outstanding at end of period (USD per share)
Weighted Average Grant Date Fair Value
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Non-vested outstanding at beginning of period (USD per share)
Share-based Compensation Arrangement by Share-based Payment Award, Option, Nonvested, Weighted Average Exercise Price
Vested (USD per share)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Weighted Average Grant Date Fair Value
Forfeited (USD per share)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Weighted Average Grant Date Fair Value
Non-vested outstanding at end of period (USD per share)
Operating leases
Lessee, Operating Leases [Text Block]
Restructuring Reserve [Roll Forward]
Restructuring Reserve [Roll Forward]
Provision, beginning balance
Restructuring Reserve
Utilization
Restructuring Reserve Utilizations
Restructuring Reserve Utilizations
Provision, ending balance
Statement of Financial Position [Abstract]
ASSETS
Assets [Abstract]
Current Assets:
Assets, Current [Abstract]
Cash and cash equivalents
Cash and Cash Equivalents, at Carrying Value
Available for sale investments
Debt Securities, Available-for-sale, Current
Accounts receivable, net of allowance for credit losses
Accounts Receivable, after Allowance for Credit Loss, Current
Unbilled revenue
Contract with Customer, Asset, Gross, Current
Other receivables
Nontrade Receivables, Current
Prepayments and other current assets
Prepaid Expense and Other Assets, Current
Income taxes receivable
Income Taxes Receivable, Current
Total current assets
Assets, Current
Other Assets:
Assets, Noncurrent [Abstract]
Property, plant and equipment, net
Property, Plant and Equipment, Net
Operating right-of-use assets
Operating Lease, Right-of-Use Asset
Other non-current assets
Other Assets, Noncurrent
Non-current income taxes receivable
Income Taxes Receivable, Noncurrent
Non-current deferred tax asset
Deferred Income Tax Assets, Net
Investments in equity-long term
Long-term Investments
Intangible assets
Finite-Lived Intangible Assets, Net
Total Assets
Assets
LIABILITIES AND SHAREHOLDERS’ EQUITY
Liabilities and Equity [Abstract]
Current Liabilities:
Liabilities, Current [Abstract]
Accounts payable
Accounts Payable, Current
Unearned revenue
Contract with Customer, Liability, Current
Other liabilities
Other Liabilities, Current
Income taxes payable
Accrued Income Taxes, Current
Current bank credit lines and loan facilities
Line of Credit, Current
Total current liabilities
Liabilities, Current
Other Liabilities:
Liabilities, Noncurrent [Abstract]
Non-current operating lease liabilities
Operating Lease, Liability, Noncurrent
Non-current other liabilities
Other Liabilities, Noncurrent
Non-current government grants
Capital Government Grants Noncurrent
Noncurrent capital government grants, which are amortized and recognized in earnings over the grant period.
Non-current income taxes payable
Accrued Income Taxes, Noncurrent
Non-current deferred tax liability
Deferred Income Tax Liabilities, Net
Commitments and contingencies
Commitments and Contingencies
Total Liabilities
Liabilities
Shareholders' Equity:
Stockholders' Equity Attributable to Parent [Abstract]
Ordinary shares, par value 6 euro cents per share; 100,000,000 shares authorized, 52,508,751 shares issued and outstanding at March 31, 2020 and 53,622,206 shares issued and outstanding at December 31, 2019
Common Stock, Value, Issued
Additional paid‑in capital
Additional Paid in Capital, Common Stock
Other undenominated capital
Other Undenominated Capital
Other undenominated capital.
Accumulated other comprehensive income
Accumulated Other Comprehensive Income (Loss), Net of Tax
Retained earnings
Retained Earnings (Accumulated Deficit)
Total Shareholders' Equity
Stockholders' Equity Attributable to Parent
Redeemable noncontrolling interest
Redeemable Noncontrolling Interest, Equity, Carrying Amount
Total Shareholders' Equity and Redeemable Noncontrolling Interest
Stockholders Equity Attributable To Parent And Redeemable Noncontrolling Interest, Equity, Carrying Amount
Stockholders Equity Attributable To Parent And Redeemable Noncontrolling Interest, Equity, Carrying Amount
Total Liabilities and Shareholders' Equity and Redeemable Noncontrolling Interest
Liabilities and Equity
Ordinary shares, par value (in EUR per share)
Common Stock, Par or Stated Value Per Share
Ordinary shares, shares authorized (in shares)
Common Stock, Shares Authorized
Ordinary shares, shares issued (in shares)
Common Stock, Shares, Issued
Ordinary shares, shares outstanding (in shares)
Common Stock, Shares, Outstanding
Revenue
Revenue from Contract with Customer [Text Block]
Performance Share Unit (PSUs)
Performance Share Unit [Member]
Performance Share Unit [Member]
Restricted Stock Units (RSUs)
Restricted Stock Units (RSUs) [Member]
Outstanding Number of Shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at beginning of period (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number
Granted (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period
Shares vested (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period
Forfeited (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period
Outstanding at end of period (in shares)
Weighted Average Grant Date Fair Value
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Outstanding at beginning of period (USD per share)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value
Granted (USD per share)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value
Shares vested (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
Forfeited (USD per share)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value
Outstanding at end of period (USD per share)
Weighted Average Remaining Contractual Life
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Outstanding at end of period (in years)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms
Significant accounting policies
Significant Accounting Policies [Text Block]
Equity [Abstract]
Share capital
Stockholders' Equity Note Disclosure [Text Block]
Class of Treasury Stock [Table]
Class of Treasury Stock [Table]
Share Repurchase Program
Share Repurchase Program [Axis]
Share Repurchase Program [Domain]
Share Repurchase Program [Domain]
Buyback Program
Buyback Program [Member]
Buyback Program [Member]
Statistical Measurement [Axis]
Statistical Measurement [Axis]
Statistical Measurement [Domain]
Statistical Measurement [Domain]
Maximum
Maximum [Member]
Equity, Class of Treasury Stock [Line Items]
Equity, Class of Treasury Stock [Line Items]
Share repurchase program, authorized percentage
Stock Repurchase Program Authorized Percentage
Stock Repurchase Program Authorized Percentage
Share repurchase program, number of shares authorized to be repurchased (in shares)
Stock Repurchase Program, Number of Shares Authorized to be Repurchased
Shares redeemed, value
Stock Repurchased and Retired During Period, Value
Shares redeemed (in shares)
Stock Repurchased and Retired During Period, Shares
Schedule of Goodwill
Schedule of Goodwill [Table Text Block]
Accounting Changes and Error Corrections [Abstract]
Impact of change in accounting policies
New Accounting Pronouncements and Changes in Accounting Principles [Text Block]
Document And Entity Information [Abstract]
Document And Entity Information [Abstract]
Document Type
Document Type
Amendment Flag
Amendment Flag
Document Period End Date
Document Period End Date
Document Fiscal Year Focus
Document Fiscal Year Focus
Document Fiscal Period Focus
Document Fiscal Period Focus
Entity Registrant Name
Entity Registrant Name
Entity Central Index Key
Entity Central Index Key
Current Fiscal Year End Date
Current Fiscal Year End Date
Income from operations, including restructuring
Operating lease costs
Operating Lease, Cost
Income from sub-leases
Sublease Income
Net operating lease costs
Lease, Cost
Schedule of Contracts with Customers, Asset and Liabilities
Contract with Customer, Asset and Liability [Table Text Block]
Restructuring
Restructuring and Related Activities Disclosure [Text Block]
Net income
Noncontrolling interest adjustment to redemption amount
Temporary Equity, Accretion to Redemption Value, Adjustment
Net income attributable to the Group (including NCI redemption adjustment)
Net Income (Loss) Available to Common Stockholders, Basic
Net income per Ordinary Share attributable to the Group (including NCI redemption adjustment):
Earnings Per Share, Basic and Diluted [Abstract]
Weighted average number of ordinary shares outstanding for basic net income per ordinary share (in shares)
Effect of dilutive share options outstanding (in shares)
Weighted Average Number Diluted Shares Outstanding Adjustment
Weighted average number of ordinary shares outstanding for diluted net income per ordinary share (in shares)
Compensation Related Costs Share Based Payments Disclosure [Table]
Compensation Related Costs Share Based Payments Disclosure [Table]
Compensation Related Costs Share Based Payments Disclosure [Table]
Title of Individual [Axis]
Title of Individual [Axis]
Title of Individual [Domain]
Title of Individual [Domain]
Non-executive directors
Non-executive Director [Member]
Non-executive Director [Member]
Award Date [Axis]
Award Date [Axis]
Award Date [Domain]
Award Date [Domain]
Award Date, All years excluding 2018
Award Date, All Years Excluding 2018 [Member]
Award Date, Prior to 2018 [Member]
Award Date, 2018
Award Date, 2018 [Member]
Award Date, 2018 [Member]
Consultants Stock Plan, 2008 Plan
Consultants Stock Plan, 2008 Plan [Member]
Consultants Stock Plan, 2008 Plan [Member]
Employee Stock Plan, 2008 Plan
Employee Stock Plan, 2008 Plan [Member]
Employee Stock Plan, 2008 Plan [Member]
Option Plans 2008
Option Plans 2008 [Member]
Option Plans 2008 [Member]
Employee Stock Plan, 2003 Plan
Employee Stock Plan, 2003 Plan [Member]
Employee Stock Plan, 2003 Plan [Member]
Restricted Stock Units 2013
Restricted Stock Units Twenty Thirteen [Member]
Restricted Stock Units Twenty Thirteen [Member]
Consultants Restricted Stock Units 2019
Consultants Restricted Stock Units Twenty Nineteen [Member]
Consultants Restricted Stock Units Twenty Nineteen [Member]
PSUs Based on Service and EPS Targets
Performance Based Grants [Member]
Performance Based Grants [Member]
Minimum
Minimum [Member]
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]
Ordinary shares which have been reserved for issuance (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized
Limit of shares issued or to be issued pursuant to options granted (in shares)
Limit Of Shares Issued Or To Be Issued Pursuant To Options Granted
Limit of Shares Issued or To Be Issued Pursuant to Options Granted
Maximum number of shares per employee (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares Per Employee
Percentage of option price for fair value of ordinary share
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent
Maximum number of award as percentage of shares outstanding
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Outstanding Stock Maximum
Shares vesting period
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period
Shares expiration period
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period
Weighted average contractual term of options outstanding
Options outstanding fair value (USD per share)
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Option Price
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Option Price
Weighted average fair value per option (USD per share)
Share Based Compensation Arrangement by Share Based Payment Award, Options, Grants in Period, Weighted Average Option Price
Share Based Compensation Arrangement by Share Based Payment Award, Options, Grants in Period, Weighted Average Option Price
Exercisable - number of shares
Exercisable - weighted average remaining contractual life
Exercisable - weighted average exercise price (USD per share)
Fully vested total intrinsic value
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value
Intrinsic value of option exercised
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value
Ordinary shares which have been reserved for issuance (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized
Fair value of stock units vested
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value
Stock units to be granted (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant
Non-cash stock compensation expense not yet recognized
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount
Unrecognized stock-based compensation expense, weighted average period
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition
Schedule of Lease Costs
Lease, Cost [Table Text Block]
Schedule of Operating Lease Maturity
Lessee, Operating Lease, Liability, Maturity [Table Text Block]
Net income per ordinary share
Earnings Per Share [Text Block]
Provision for income taxes
Business segment information
Segment Reporting Disclosure [Text Block]
Disaggregation of Revenue [Table]
Disaggregation of Revenue [Table]
Customer [Axis]
Customer [Axis]
Customer [Domain]
Customer [Domain]
Top client
Top Client [Member]
Top Client [Member]
Clients 2-5
Clients 2-5 [Member]
Clients 2-5 [Member]
Clients 6-10
Clients 6-10 [Member]
Clients 6-10 [Member]
Clients 11-25
Clients 11-25 [Member]
Clients 11-25 [Member]
Other
Other Customers [Member]
Other Customers [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue [Line Items]
Income taxes
Income Tax Disclosure [Text Block]
New Accounting Pronouncements or Change in Accounting Principle [Table]
New Accounting Pronouncements or Change in Accounting Principle [Table]
Equity Components [Axis]
Equity Components [Axis]
Equity Component [Domain]
Equity Component [Domain]
Retained Earnings
Retained Earnings [Member]
Adjustments for New Accounting Pronouncements [Axis]
Adjustments for New Accounting Pronouncements [Axis]
Type of Adoption [Domain]
Type of Adoption [Domain]
Accounting Standards Update 2016-02
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Liability due to former noncontrolling interest holders
Shareholders' equity
Share-based awards
Share-based Payment Arrangement [Text Block]
Billed services (accounts receivable)
Accounts Receivable, before Allowance for Credit Loss, Current
Unbilled services (unbilled revenue)
Accounts receivable and unbilled revenue
Contracts Receivable, Gross
Contracts Receivable
Allowance for credit losses
Accounts Receivable, Allowance for Credit Loss
Accounts receivable and unbilled revenue, net
Contracts Receivable, Net
Contracts Receivable, Net
Unearned revenue (payments on account)
Net balance
Advance Payments Netted Against Unbilled Contracts Receivable
Advance Payments Netted Against Unbilled Contracts Receivable
Change in unbilled services (unbilled revenue)
Increase (Decrease) In Contract with Customer, Asset, Gross, Current
Increase (Decrease) In Contract with Customer, Asset, Gross, Current
Change in unearned revenue (payments on account)
Increase (Decrease) In Contract With Customer, Liability, Current
Increase (Decrease) In Contract With Customer, Liability, Current
Change in net balance
Change in Advance Payments Netted Against Unbilled Contracts Receivable
Change in Advance Payments Netted Against Unbilled Contracts Receivable
Change in unbilled services (unbilled revenue), percent
Increase (Decrease) In Contract with Customer, Asset, Gross, Current, Percent
Increase (Decrease) In Contract with Customer, Asset, Gross, Current, Percent
Change in unearned revenue (payments on account), percent
Increase (Decrease) In Contract With Customer, Liability, Gross, Current, Percent
Increase (Decrease) In Contract with Customer, Liability, Gross, Current, Percent
Change in net balance, percent
Change in Advance Payments Netted Against Unbilled Contracts Receivable, Percent
Change in Advance Payments Netted Against Unbilled Contracts Receivable, Percent
Statement of Stockholders' Equity [Abstract]
Statement [Table]
Statement [Table]
Ordinary Shares
Common Stock [Member]
Additional Paid-in Capital
Additional Paid-in Capital [Member]
Other Undenominated Capital
Other Undenominated Capital [Member]
Other undenominated capital.
Accumulated Other Comprehensive Income
AOCI Attributable to Parent [Member]
Redeemable Noncontrolling Interest
Redeemable Noncontrolling Interest [Member]
Redeemable Noncontrolling Interest [Member]
Statement [Line Items]
Statement [Line Items]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)
Beginning balance
Comprehensive income:
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Currency translation adjustment
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax
Currency impact of long term funding (net of tax)
Other Comprehensive Income (Loss), Foreign Currency Transaction And Translation Adjustment, Net Of Tax, Long-Term Funding
Adjustment that results from the process of translating the impact of long-term funding into the functional currency of the reporting entity.
Transfer to realized capital gain
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax
Amortization of interest rate hedge
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax
Fair value of cash flow hedge (net of tax)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax
Total comprehensive income
Comprehensive Income (Loss), Net of Tax, Attributable to Parent
Exercise of share options (in shares)
Exercise of share options
Stock Issued During Period, Value, Stock Options Exercised
Issue of restricted share units (in shares)
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture
Issue of restricted share units
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture
Non-cash stock compensation expense
APIC, Share-based Payment Arrangement, Increase for Cost Recognition
Share issuance costs
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs
Share repurchase program (in shares)
Share repurchase program
Share repurchase costs
Adjustment to Retained Earning Share Repurchase costs
Adjustment to Retained Earning Share Repurchase costs
Noncontrolling interest adjustment to redemption amount
Redeemable Noncontrolling Interest, Accretion To Redemption Value
Redeemable Noncontrolling Interest, Accretion To Redemption Value
Ending balance (in shares)
Ending balance
Increase (Decrease) in Temporary Equity [Roll Forward]
Increase (Decrease) in Temporary Equity [Roll Forward]
Beginning balance
Net income attributable to redeemable noncontrolling interest
Temporary Equity, Net Income
Total comprehensive income
Temporary Equity, Comprehensive Income (Loss)
Temporary Equity, Comprehensive Income (Loss)
Noncontrolling interest adjustment to redemption amount
Temporary Equity, Accretion to Redemption Value
Exercise of call option on noncontrolling interest shares
Redeemable Noncontrolling Interest, Decrease From Redemptions Or Purchase Of Interests
Redeemable Noncontrolling Interest, Decrease From Redemptions Or Purchase Of Interests
Ending balance
Schedule of Share Option Activity
Share-based Payment Arrangement, Option, Activity [Table Text Block]
Schedule of Movement in Non-vested Share Options
Schedule of Nonvested Share Activity [Table Text Block]
Schedule of Weighted Average Fair Values and Assumptions Used
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]
Schedule of RSU and PSU Activity
Schedule Of Share Based Compensation Restricted Stock Units Performance Stock Units Award Activity [Table Text Block]
Schedule Of Share Based Compensation Restricted Stock Units Performance Stock Units Award Activity [Table Text Block]
Schedule of Non-cash Stock Compensation Expense
Schedule of Non Cash Stock Compensation Expense [Table Text Block]
Schedule of Non Cash Stock Compensation Expense.
Assets
Revenue, remaining performance obligation
Revenue, Remaining Performance Obligation, Amount
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, percent
Revenue, Remaining Performance Obligation, Percentage
Revenue, remaining performance obligation, expected timing of satisfaction, period
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs, by Report Line
Income Statement Location [Axis]
Income Statement Location [Domain]
Income Statement Location [Domain]
Direct costs
Cost of Sales [Member]
Selling, general and administrative
Selling, General and Administrative Expenses [Member]
Business combinations
Business Combination Disclosure [Text Block]
Long-lived assets, net
Long-Lived Assets
Schedule of Summary of Estimates of Fair Values of Assets Acquired and Liabilities Assumed
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]
Number of operating segments
Number of Operating Segments
Depreciation, amortization and reduction in carrying value of right-of-use assets
Depreciation, Amortization And Operating Lease, Right-of-Use Asset, Amortization Expense
Depreciation, Amortization And Operating Lease, Right-of-Use Asset, Amortization Expense
Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities)
Lessee, Lease, Description [Table]
Lessee, Lease, Description [Table]
Income Statement Location [Axis]
Selling, general and administration costs
Lessee, Lease, Description [Line Items]
Lessee, Lease, Description [Line Items]
Total lease cost
Right-of-use assets obtained in exchange for lease obligations
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability
Weighted average remaining lease term (in years)
Operating Lease, Weighted Average Remaining Lease Term
Weighted average discount rate
Operating Lease, Weighted Average Discount Rate, Percent
Operating lease liabilities
Operating Lease, Liability, Current
Distribution of Revenue by Geographical Area
Revenue from External Customers by Geographic Areas [Table Text Block]
Distribution of Income from Operations by Geographical Area
Operating Income by Geography [Table Text Block]
Operating Income by Geography.
Distribution of Long-lived Assets, Net, by Geographical Area
Long-lived Assets by Geographic Areas [Table Text Block]
Distribution of Depreciation and Amortization by Geographical Area
Schedule Of Depreciation And Amortization Expense By Geographical Area [Table Text Block]
Schedule Of Depreciation And Amortization Expense By Geographical Area.
Distribution of Total Assets by Geographical Area
Reconciliation of Assets from Segment to Consolidated [Table Text Block]