| Summary of Changes in Items of Property, Plant and Equipment | Changes in items of property, plant and equipment in 2022 are as follows:   
       
        |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  
        |   |   | Land andbuildings
 |   |   | Plant andmachinery
 |   |   | Industrialand
 commercial
 equipment
 |   |   | Othertangible
 assets
 |   |   | Assets underconstruction
 and
 advances
 |   |   | Total |   |  
        |   |   | (EUR thousand) |   |  
        | Cost |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |  
        | At January 1, 2021 |   |   | 148,331 |   |   |   | 375,902 |   |   |   | 41,189 |   |   |   | 11,316 |   |   |   | 61,293 |   |   |   | 638,031 |   |  
        | Additions |   |   | 2,060 |   |   |   | 26,826 |   |   |   | 3,862 |   |   |   | 913 |   |   |   | 82,970 |   |   |   | 116,631 |   |  
        | Disposals |   |   | (141 | ) |   |   | (7,759 | ) |   |   | (1,188 | ) |   |   | (421 | ) |   |   | (35 | ) |   |   | (9,544 | ) |  
        | Reclassifications |   |   | 7,719 |   |   |   | 44,412 |   |   |   | 2,027 |   |   |   | 856 |   |   |   | (55,014 | ) |   |   | — |   |  
        | Exchange differences |   |   | 1,946 |   |   |   | 6,358 |   |   |   | 379 |   |   |   | 227 |   |   |   | 732 |   |   |   | 9,642 |   |  
        | At December 31, 2021 |   |   | 159,915 |   |   |   | 445,739 |   |   |   | 46,269 |   |   |   | 12,891 |   |   |   | 89,946 |   |   |   | 754,760 |   |  
        | Additions |   |   | 2,306 |   |   |   | 39,399 |   |   |   | 3,524 |   |   |   | 1,337 |   |   |   | 247,961 |   |   |   | 294,527 |   |  
        | Disposals |   |   | (293 | ) |   |   | (2,693 | ) |   |   | (18 | ) |   |   | (249 | ) |   |   | (61 | ) |   |   | (3,314 | ) |  
        | Reclassifications |   |   | 1,386 |   |   |   | 33,917 |   |   |   | 1,467 |   |   |   | 821 |   |   |   | (37,591 | ) |   |   | — |   |  
        | Exchange differences |   |   | 3,109 |   |   |   | 7,402 |   |   |   | 398 |   |   |   | 382 |   |   |   | (1,728 | ) |   |   | 9,563 |   |  
        | At December 31, 2022 |   |   | 166,423 |   |   |   | 523,764 |   |   |   | 51,640 |   |   |   | 15,182 |   |   |   | 298,527 |   |   |   | 1,055,535 |   |  
        |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |  
        | Depreciation and impairment |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |  
        | At January 1, 2021 |   |   | 63,563 |   |   |   | 222,804 |   |   |   | 29,900 |   |   |   | 8,107 |   |   |   | — |   |   |   | 324,374 |   |  
        | Depreciation charge for the year |   |   | 5,319 |   |   |   | 29,549 |   |   |   | 5,660 |   |   |   | 1,206 |   |   |   | — |   |   |   | 41,734 |   |  
        | Impairment |   |   | — |   |   |   | 547 |   |   |   | 396 |   |   |   | — |   |   |   | — |   |   |   | 943 |   |  
        | Disposals |   |   | (140 | ) |   |   | (7,330 | ) |   |   | (1,053 | ) |   |   | (410 | ) |   |   | — |   |   |   | (8,933 | ) |  
        | Exchange differences |   |   | 689 |   |   |   | 2,912 |   |   |   | 154 |   |   |   | 170 |   |   |   | — |   |   |   | 3,925 |   |  
        | At December 31, 2021 |   |   | 69,431 |   |   |   | 248,482 |   |   |   | 35,057 |   |   |   | 9,073 |   |   |   | — |   |   |   | 362,043 |   |  
        | Depreciation charge for the year |   |   | 5,948 |   |   |   | 36,628 |   |   |   | 6,250 |   |   |   | 1,512 |   |   |   | — |   |   |   | 50,338 |   |  
        | Impairment |   |   | — |   |   |   | 44 |   |   |   | — |   |   |   | — |   |   |   | — |   |   |   | 44 |   |  
        | Disposals |   |   | (293 | ) |   |   | (2,210 | ) |   |   | (5 | ) |   |   | (240 | ) |   |   | — |   |   |   | (2,748 | ) |  
        | Exchange differences |   |   | 793 |   |   |   | 3,291 |   |   |   | 130 |   |   |   | 243 |   |   |   | — |   |   |   | 4,457 |   |  
        | At December 31, 2022 |   |   | 75,879 |   |   |   | 286,235 |   |   |   | 41,432 |   |   |   | 10,588 |   |   |   | — |   |   |   | 414,134 |   |  
        |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |  
        | Net book value |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |  
        | At December 31, 2022 |   |   | 90,544 |   |   |   | 237,529 |   |   |   | 10,208 |   |   |   | 4,594 |   |   |   | 298,527 |   |   |   | 641,402 |   |  
        | At December 31, 2021 |   |   | 90,484 |   |   |   | 197,257 |   |   |   | 11,212 |   |   |   | 3,818 |   |   |   | 89,946 |   |   |   | 392,717 |   |    |