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Investments - Additional Information (Detail) - EUR (€) € in Thousands | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2019 | Jun. 30, 2018 | Dec. 31, 2018
Investment [Line Items] |  |  |  |  |
Non-current investments | € 12,319 |  | € 12,319 |  | € 16,945
Purchases of investments |  |  | 30,551 | € 29,560 |
Proceeds from investment maturities |  |  | 45,114 | 18,931 |
Foreign currency exchange gains |  | € 6,917 | 871 | € 4,111 |
Foreign currency exchange losses | 1,083 |  |  |  |
Mature in 12 months [member] |  |  |  |  |
Investment [Line Items] |  |  |  |  |
Non-current investments | 6,500 |  | 6,500 |  |
Finance Income Expense [Member] |  |  |  |  |
Investment [Line Items] |  |  |  |  |
Foreign currency exchange gains | € 400 |  |  |  |
Foreign currency exchange losses |  |  | € 700 |  |

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- Definition The amount of non-current held-to-maturity investments. [Refer: Held-to-maturity investments] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Note Expiry date 2021-01-01 -Name IFRS -Number 7 -IssueDate 2018-01-01 -Paragraph 8 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-02&anchor=para_8_b&doctype=Standard&book=b -URIDate 2018-03-16 + Details
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- Definition The cash inflow from sales or maturity of financial instruments, classified as investing activities. [Refer: Financial instruments, class [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2018-01-01 -Paragraph 16 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2018-03-01&anchor=para_16&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition The cash outflow for the purchase of financial instruments. [Refer: Financial instruments, class [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2018-01-01 -Paragraph 16 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2018-03-01&anchor=para_16&doctype=Standard -URIDate 2018-03-16 + Details
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