XML 52 R45.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Share-based Awards - Narrative (Detail) - USD ($) $ / shares in Units, $ in Millions |  |  | 3 Months Ended | 6 Months Ended | 12 Months Ended | 66 Months Ended
--- | --- | --- | --- | --- | --- | ---
Feb. 14, 2017 | May 11, 2015 | Jun. 30, 2018 | Jun. 30, 2018 | Jun. 30, 2017 | Dec. 31, 2017 | Jun. 30, 2018
Compensation Related Costs Share Based Payments Disclosure [Line Items] |  |  |  |  |  |  |
Limit of shares issued or to be issued pursuant to options granted |  |  | 1,000,000 |  |  |  |
Non-cash stock compensation expense not yet recognized |  |  | $ 60.2 | $ 60.2 |  |  | $ 60.2
Unrecognized stock-based compensation expense, weighted average period (years) |  |  |  | 2 years 6 months 6 days |  |  |
Restricted Stock Units (RSUs) |  |  |  |  |  |  |
Compensation Related Costs Share Based Payments Disclosure [Line Items] |  |  |  |  |  |  |
Fair value of stock units vested |  |  |  | $ 18.4 |  | $ 16.6 |
Stock units granted |  |  |  | 158,775 |  |  |
Performance Share Unit (PSUs) |  |  |  |  |  |  |
Compensation Related Costs Share Based Payments Disclosure [Line Items] |  |  |  |  |  |  |
Fair value of stock units vested |  |  |  | $ 14.7 |  | $ 15.0 |
Stock units granted |  |  |  | 71,906 |  |  |
PSUs Based on Service and EPS Targets |  |  |  |  |  |  |
Compensation Related Costs Share Based Payments Disclosure [Line Items] |  |  |  |  |  |  |
Stock units granted |  |  |  |  |  |  | 147,630
PSUs Based on Service and EPS Targets | Minimum |  |  |  |  |  |  |
Compensation Related Costs Share Based Payments Disclosure [Line Items] |  |  |  |  |  |  |
Cumulative EPS vesting period |  |  |  | 2015 |  |  |
PSUs Based on Service and EPS Targets | Maximum |  |  |  |  |  |  |
Compensation Related Costs Share Based Payments Disclosure [Line Items] |  |  |  |  |  |  |
Stock units to be granted |  |  | 103,423 | 103,423 |  |  | 103,423
Cumulative EPS vesting period |  |  |  | 2021 |  |  |
Employee Stock Plan, 2008 Plan |  |  |  |  |  |  |
Compensation Related Costs Share Based Payments Disclosure [Line Items] |  |  |  |  |  |  |
Ordinary shares which have been reserved for issuance |  |  | 6,000,000 | 6,000,000 |  |  | 6,000,000
Employee Stock Plan, 2008 Plan | Minimum |  |  |  |  |  |  |
Compensation Related Costs Share Based Payments Disclosure [Line Items] |  |  |  |  |  |  |
Additional number of ordinary shares which have been reserved for issuance | 400,000 |  |  |  |  |  |
Percentage of option price for fair value of ordinary share |  |  |  | 100.00% |  |  |
Employee Stock Plan, 2008 Plan | Maximum |  |  |  |  |  |  |
Compensation Related Costs Share Based Payments Disclosure [Line Items] |  |  |  |  |  |  |
Additional number of ordinary shares which have been reserved for issuance | 1,000,000 |  |  |  |  |  |
Employee Stock Plan, 2003 Plan |  |  |  |  |  |  |
Compensation Related Costs Share Based Payments Disclosure [Line Items] |  |  |  |  |  |  |
Ordinary shares which have been reserved for issuance |  |  | 6,000,000 | 6,000,000 |  |  | 6,000,000
Maximum number of award as percentage of shares outstanding |  |  |  | 10.00% |  |  |
Employee Stock Plan, 2003 Plan | Individual Employee |  |  |  |  |  |  |
Compensation Related Costs Share Based Payments Disclosure [Line Items] |  |  |  |  |  |  |
Ordinary shares which have been reserved for issuance |  |  | 400,000 | 400,000 |  |  | 400,000
Employee Stock Option |  |  |  |  |  |  |
Compensation Related Costs Share Based Payments Disclosure [Line Items] |  |  |  |  |  |  |
Shares vesting period |  |  |  | 5 years |  |  |
Shares expiration period |  |  |  | 8 years |  |  |
Weighted average contractual term of options outstanding |  |  |  | 5 years 29 days |  |  |
Weighted average fair value per option |  |  |  | $ 13.2 |  |  |
Exercisable - number of shares |  |  | 562,223 | 562,223 |  |  | 562,223
Exercisable - weighted average remaining contractual life |  |  |  | 3 years 9 months 18 days |  |  |
Exercisable - weighted average exercise price |  |  | $ 48.81 | $ 48.81 |  |  | $ 48.81
Fully vested total intrinsic value |  |  | $ 47.1 | $ 47.1 |  |  | $ 47.1
Intrinsic value of option exercised |  |  |  | $ 18.5 | $ 14.0 |  |
Employee Stock Option | Minimum |  |  |  |  |  |  |
Compensation Related Costs Share Based Payments Disclosure [Line Items] |  |  |  |  |  |  |
Options outstanding fair value |  |  | $ 8.53 | $ 8.53 |  |  | $ 8.53
Employee Stock Option | Maximum |  |  |  |  |  |  |
Compensation Related Costs Share Based Payments Disclosure [Line Items] |  |  |  |  |  |  |
Weighted average contractual term of options outstanding |  |  |  | 8 years |  |  |
Options outstanding fair value |  |  | $ 39.96 | $ 39.96 |  |  | $ 39.96
Restricted Stock Units 2008 |  |  |  |  |  |  |
Compensation Related Costs Share Based Payments Disclosure [Line Items] |  |  |  |  |  |  |
Ordinary shares which have been reserved for issuance |  |  | 1,000,000 | 1,000,000 |  |  | 1,000,000
Restricted Stock Units 2013 |  |  |  |  |  |  |
Compensation Related Costs Share Based Payments Disclosure [Line Items] |  |  |  |  |  |  |
Additional number of ordinary shares which have been reserved for issuance |  | 2,500,000 |  |  |  |  |
Ordinary shares which have been reserved for issuance |  | 4,100,000 |  |  |  |  |

X
- Definition Compensation Related Costs Share Based Payments Disclosure [Line Items] + References No definition available. + Details
Name: | iclr_CompensationRelatedCostsShareBasedPaymentsDisclosureLineItems
Namespace Prefix: | iclr_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Limit of Shares Issued or To Be Issued Pursuant to Options Granted + References No definition available. + Details
Name: | iclr_LimitofSharesIssuedorToBeIssuedPursuanttoOptionsGranted
Namespace Prefix: | iclr_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Share Based Compensation Arrangement by Share Based Payment Award, Options, Grants in Period, Weighted Average Option Price + References No definition available. + Details
Name: | iclr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageOptionPrice
Namespace Prefix: | iclr_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Option Price + References No definition available. + Details
Name: | iclr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingOptionPrice
Namespace Prefix: | iclr_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Share Based Compensation Arrangement by Share Based Payment Award Other Than Options Expected Vesting Period + References No definition available. + Details
Name: | iclr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsExpectedVestingPeriod
Namespace Prefix: | iclr_
Data Type: | xbrli:gYearItemType
Balance Type: | na
Period Type: | duration

X
- Definition Unrecognized cost of unvested share-based compensation awards. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of additional shares authorized for issuance under an established share-based compensation plan. + References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iii) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iii) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Maximum number of shares that may be issued in accordance with the plan as a proportion of outstanding capital stock. + References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Purchase price of common stock expressed as a percentage of its fair value. + References No definition available. + Details
Name: | us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=iclr_PerformanceShareUnitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=iclr_PerformanceBasedGrantsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=iclr_EmployeeStockPlanTwentyZeroEightPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=iclr_EmployeeStockPlanTwentyZeroThreePlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PlanNameAxis=iclr_EmployeeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=iclr_RestrictedStockUnitsTwentyZeroEightMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=iclr_RestrictedStockUnitsTwentyThirteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |