XML 142 R199.htm IDEA: XBRL DOCUMENT v3.20.1
Income Tax Expense - Summary of Tax Loss Carry Forward (Detail) - EUR (€)
€ in Thousands
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Disclosure Of Tax Loss Carryforwards [line items]    
Total € 399,821 € 393,630
No expiration [member]    
Disclosure Of Tax Loss Carryforwards [line items]    
Total 339,563 328,650
Not More than Five Years [Member]    
Disclosure Of Tax Loss Carryforwards [line items]    
Total € 26,180 € 25,647
Expiration Date 2020-2024 2019-2023
More than Five Years [Member]    
Disclosure Of Tax Loss Carryforwards [line items]    
Total € 34,078 € 39,333
Expiration Date 2024 2023