Executive and Supervisory Board Compensation - Supervisory Board Compensation (Details) - Supervisory Board Members - EUR (€) € in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Executive and Supervisory Board Compensation
Total compensation	€ 3,702	€ 3,663	€ 3,652
Thereof fixed compensation	3,162	3,135	3,135
Thereof committee remuneration	€ 540	€ 528	€ 517

The amount of remuneration paid or payable to the entity's directors.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 112
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_112_c&doctype=Standard
-URIDate 2018-03-16

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