XML 59 R52.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Distribution of Net Revenue by Geographical Area (Detail) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017
Segment Reporting Information [Line Items] |  |  |  |
Revenue | $ 641,610 | $ 591,781 | $ 1,261,735 | $ 1,169,847
Ireland |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenue | 260,120 | 231,315 | 495,230 | 463,663
Rest of Europe |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenue | 96,692 | 78,922 | 191,732 | 151,479
U.S. |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenue | 221,201 | 229,938 | 446,871 | 453,020
Rest of World |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenue | $ 63,597 | $ 51,606 | $ 127,902 | $ 101,685

X
- Definition Amount of revenue earned from products sold or services provided under the terms of a contract, including, but not limited to, government contracts and construction contracts, classified as other. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
Name: | us-gaap_ContractsRevenue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_SegmentReportingInformationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementGeographicalAxis=country_IE
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementGeographicalAxis=iclr_RestOfEuropeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementGeographicalAxis=country_US
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementGeographicalAxis=iclr_RestOfWorldMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |