Business combinations and capital reorganization - Summary of Operating Results of MOMA (Detail) - MOMA acquisition [member] € in Thousands  | 
6 Months Ended | 
|---|---|
| 
 Jun. 30, 2022  
EUR (€) 
 | |
| Disclosure of detailed information about business combination [line items] | |
| Revenue | € 470 | 
| Other income | 5 | 
| General and administrative expenses | (441) | 
| Operating profit | 34 | 
| Finance costs | (9) | 
| Profit before income tax | 25 | 
| Income tax | (10) | 
| Profit for the half-year | € 15 | 
| X | ||||||||||
- Definition Finance costs of cquiree. No definition available. 
  | 
| X | ||||||||||
- Definition General and administrative expenses. No definition available. 
  | 
| X | ||||||||||
- Definition Income tax of acquiree. No definition available. 
  | 
| X | ||||||||||
- Definition Operating profit of acquiree. No definition available. 
  | 
| X | ||||||||||
- Definition Other income of Acquiree. No definition available. 
  | 
| X | ||||||||||
- Definition Profit before income tax of acquiree. No definition available. 
  | 
| X | ||||||||||
- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table. No definition available. 
  | 
| X | ||||||||||
- Definition The profit (loss) of the acquiree, since the acquisition date, included in the consolidated statement of comprehensive income. [Refer: Profit (loss)] Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
  | 
| X | ||||||||||
- Definition The amount of revenue of the acquiree since the acquisition date included in the consolidated statement of comprehensive income. [Refer: Revenue] Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
  | 
| X | ||||||||||
- Details 
  |