Finance Income (Expense) - Additional Information (Detail) € in Millions, $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019 EUR (€)	Jun. 30, 2018 EUR (€)	Jun. 30, 2019 EUR (€)	Jun. 30, 2018 EUR (€)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)
Rental expenses on real estate [abstract]
Foreign exchange gain (loss) \| €	€ (1.1)	€ 6.9	€ 0.9	€ 4.1
Foreign currency denominated cash and cash equivalent accounts and investment \| $					$ 31.1	$ 54.5

The amount of exchange differences recognised in profit or loss that arise from foreign currency transactions, excluding those arising on financial instruments measured at fair value through profit or loss in accordance with IFRS 9. [Refer: At fair value [member]; Financial instruments, class [member]]

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 7
-IssueDate 2018-01-01
-Section A Statement of cash flows for an entity other than a financial institution
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2018-03-01&anchor=sect_AStatementofcashflowsforanentityotherthanafinancialinstitution&doctype=Illustrative%20Examples
-URIDate 2018-03-16

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 21
-IssueDate 2018-01-01
-Paragraph 52
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=21&date=2018-03-01&anchor=para_52_a&doctype=Standard
-URIDate 2018-03-16

Name:	ifrs-full_GainsLossesOnExchangeDifferencesOnTranslationRecognisedInProfitOrLoss
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration