Share-based Plans - Stock Options Other Disclosure (Details) - EUR (€)	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017
Disclosure of terms and conditions of share-based payment arrangement [line items]
Proceeds from exercise of stock options	€ 5,839,000	€ 33,737,000

The cash inflow from the exercise of options.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 7
-IssueDate 2017-01-01
-Paragraph 17
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2017-03-01&anchor=para_17&doctype=Standard
-URIDate 2017-03-09

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration