Share capital and reserves - Listing and Share Transaction Costs (Details) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share Capital, Reserves and Other Equity Interest [Abstract]
Share issue related cost, beginning balance	€ 13.8	€ 13.8
Share issue related cost	(11.1)	0.0	€ (0.5)
Share issue related cost, ending balance	€ 24.9	€ 13.8	€ 13.8

The amount of cost related to the issuance of shares.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 106
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_106_d&doctype=Standard
-URIDate 2019-03-27

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