Notes to the statement of financial position - Trade receivables, other financial assets, movement in provision for impaired receivables (Details) - Trade receivables - EUR (€) € in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Disclosure of impairment loss recognised or reversed [line items]
Beginning of Period	€ 7,276	€ 5,814
Addition	3,780	4,585
Utilization	(680)	(28)
Unused amounts reversed	(5,736)	(3,099)
Currency translation	(287)	4
End of Period	€ 4,353	€ 7,276

The amount of additional allowance for credit losses of financial assets recognised in profit or loss. [Refer: Allowance account for credit losses of financial assets]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Note Expiry date 2018-01-01
-Name IFRS
-Number 7
-IssueDate 2017-01-01
-Paragraph 16
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-02&anchor=para_16&doctype=Standard&book=B
-URIDate 2017-03-09

+ Details

Name:	ifrs-full_AdditionalAllowanceRecognisedInProfitOrLossAllowanceAccountForCreditLossesOfFinancialAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of an allowance account used to record impairments to financial assets due to credit losses. [Refer: Financial assets]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IFRS
-Number 7
-IssueDate 2017-01-01
-Paragraph 16
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-02&anchor=para_16&doctype=Standard&book=B
-URIDate 2017-03-09

+ Details

Name:	ifrs-full_AllowanceAccountForCreditLossesOfFinancialAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

+ References

No definition available.

+ Details

Name:	ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The increase (decrease) in an allowance account for credit losses of financial assets resulting from the net exchange differences arising when the financial statements are translated from the functional currency into a different presentation currency, including the translation of a foreign operation into the presentation currency of the reporting entity. [Refer: Allowance account for credit losses of financial assets]

+ References

+ Details

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

- Definition

The decrease in an allowance account for credit losses of financial assets resulting from the reversal of impairment. [Refer: Allowance account for credit losses of financial assets]

+ References

+ Details

Name:	ifrs-full_ReversalAllowanceAccountForCreditLossesOfFinancialAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

The decrease in an allowance account for credit losses of financial assets resulting from the utilisation of the allowance. [Refer: Allowance account for credit losses of financial assets]

+ References

+ Details

Name:	ifrs-full_UtilisationAllowanceAccountForCreditLossesOfFinancialAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	ifrs-full_ClassesOfFinancialAssetsAxis=ifrs-full_TradeReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: