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Share-Based Compensation - Summary of Performance-Based RSU (Detail) - 2019 performance shares [member]	6 Months Ended
	Jun. 30, 2019 EUR (€) € / shares
Disclosure of Input of Model Used for Performance-Based RSU [Line Items]
Fair value at grant date (in Euros) | € / shares	€ 10.44
Share price at grant date (in Euros) | €	€ 7.10
Dividend yield	0.00%
Expected volatility	52.00%
Risk-free interest rate (U.S. government bond yield)	2.29%
Model used	Monte Carlo

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Disclosure of input of model used for performance-based RSU.

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The description of the option pricing model used for share options granted. [Refer: Option pricing model [member]]

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2018-01-01
-Paragraph 47
-Subparagraph a
-Clause i
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2018-03-01&anchor=para_47_a_i&doctype=Standard
-URIDate 2018-03-16

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