v3.26.1
Property, plant and equipment, intangible assets and Right-of-use assets - Addtional information (Detail) - EUR (€)
6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Disclosure of detailed information about property, plant and equipment [line items]      
Purchase of property, plant and equipment € 1,200,000 € 5,400,000  
Unpaid investment decreased 100,000   € 500,000
Rental Land [Member]      
Disclosure of detailed information about property, plant and equipment [line items]      
Addition to right-of-use assets 0 3,200,000  
Office Equipment And Installations [Member]      
Disclosure of detailed information about property, plant and equipment [line items]      
Leasehold improvements € 600,000 € 4,100,000