Annual and transition report of foreign private issuers pursuant to Section 13 or 15(d)

Share-Based Payment (Schedule of Weighted Average Fair Values and Exercise Price) (Details)

v3.8.0.1
Share-Based Payment (Schedule of Weighted Average Fair Values and Exercise Price) (Details) - EUR (€)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Disclosure of terms and conditions of share-based payment arrangement [abstract]      
Weighted average exercise prices € 9.02 € 8.3 € 8.96
Weighted average fair value on grant date € 1.8 € 1.6