Other non-current assets - Financial assets held at fair value through profit or loss (Details) - EUR (€) € in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of fair value remeasurement
Net book value at December 31,	€ 11,275	€ 6,000	€ 1,754
Financial assets.
Reconciliation of fair value remeasurement
Costs at January 1	4,818	2,373	2,750
Acquisitions of the year		4,736
Disposals of the year	(82)	(2,291)	(377)
Costs at December 31,	4,736	4,818	2,373
Net book value at December 31,	11,275	6,000	1,754
Financial assets. \| Level 1
Reconciliation of fair value remeasurement
Fair value adjustment at January 1	1,182	(619)	(399)
Cancellation of fair value adjustment following disposal	2	598	55
Fair value adjustment of the year	5,355	1,203	(275)
Fair value adjustment at December 31,	€ 6,539	€ 1,182	€ (619)

Fair value adjustment of financial assets

No definition available.

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- Definition

The amount of financial assets at amortised cost. The amortised cost is the amount at which financial assets are measured at initial recognition minus principal repayments, plus or minus the cumulative amortisation using the effective interest method of any difference between that initial amount and the maturity amount, and adjusted for any impairment. [Refer: Financial assets]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
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-IssueDate 2019-01-01
-Paragraph 8
-Subparagraph f
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- Definition

The amount of financial assets that are measured at fair value and for which gains (losses) are recognised in profit or loss. A financial asset shall be measured at fair value through profit or loss unless it is measured at amortised cost or at fair value through other comprehensive income. A gain (loss) on a financial asset measured at fair value shall be recognised in profit or loss unless it is part of a hedging relationship, it is an investment in an equity instrument for which the entity has elected to present gains and losses in other comprehensive income or it is a financial asset measured at fair value through other comprehensive income. [Refer: At fair value [member]; Financial assets]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
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-Paragraph 8
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- Definition

The gains (losses) including exchange differences recognised in profit or loss on the fair value measurement of assets. [Refer: At fair value [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 13
-IssueDate 2019-01-01
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-Clause i
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- Definition

The increase (decrease) in the fair value measurement of assets. [Refer: At fair value [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 13
-IssueDate 2019-01-01
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- Definition

The increase in the fair value measurement of assets resulting from purchases of those assets. [Refer: At fair value [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- References

No definition available.

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The decrease in the fair value measurement of assets resulting from sales. [Refer: At fair value [member]]

+ References

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