Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2023-12-31 |
As at 2023-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
|---|---|---|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | ||||||
| Property, plant and equipment [abstract] | ||||||
| Property, plant and equipment |
686,497,000
EUR
|
607,716,000
EUR
|
679,501,000
EUR
|
604,932,000
EUR
|
— | — |
| Intangible assets and goodwill [abstract] | ||||||
| Intangible assets and goodwill |
203,754,000
EUR
|
162,379,000
EUR
|
204,352,000
EUR
|
155,259,000
EUR
|
— | — |
| Investment property [abstract] | ||||||
| Investment property |
3,296,000
EUR
|
3,296,000
EUR
|
4,304,000
EUR
|
7,457,000
EUR
|
— | — |
| Investments in subsidiaries, joint ventures and associates reported in separate financial statements [abstract] | ||||||
| Investments in subsidiaries reported in separate financial statements | — |
36,920,000
EUR
|
— |
38,720,000
EUR
|
— | — |
| Trade and other non-current receivables [abstract] | ||||||
| Non-current prepayments and non-current accrued income other than non-current contract assets [abstract] | ||||||
| Non-current prepayments |
2,714,000
EUR
|
2,787,000
EUR
|
3,293,000
EUR
|
3,694,000
EUR
|
— | — |
| Other non-current receivables |
19,685,000
EUR
|
19,684,000
EUR
|
19,251,000
EUR
|
19,246,000
EUR
|
— | — |
| Non-current prepayments and non-current accrued income including non-current contract assets [abstract] | ||||||
| Non-current accrued income including non-current contract assets [abstract] | ||||||
| Non-current contract assets |
4,179,000
EUR
|
3,749,000
EUR
|
3,624,000
EUR
|
3,234,000
EUR
|
— | — |
| Trade and other current receivables [abstract] | ||||||
| Current prepayments and current accrued income other than current contract assets [abstract] | ||||||
| Current prepayments [abstract] | ||||||
| Current prepaid expenses |
6,743,000
EUR
|
4,855,000
EUR
|
4,545,000
EUR
|
3,741,000
EUR
|
— | — |
| Trade and other current receivables |
170,123,000
EUR
|
161,091,000
EUR
|
157,680,000
EUR
|
150,884,000
EUR
|
— | — |
| Current prepayments and current accrued income including current contract assets [abstract] | ||||||
| Current accrued income including current contract assets [abstract] | ||||||
| Current contract assets |
14,148,000
EUR
|
14,036,000
EUR
|
15,942,000
EUR
|
15,562,000
EUR
|
— | — |
| Categories of current financial assets [abstract] | ||||||
| Current financial assets |
1,046,000
EUR
|
18,002,000
EUR
|
837,000
EUR
|
11,516,000
EUR
|
— | — |
| Classes of current inventories [abstract] | ||||||
| Current inventories |
24,802,000
EUR
|
21,176,000
EUR
|
25,253,000
EUR
|
21,702,000
EUR
|
— | — |
| Classes of current inventories, alternative [abstract] | ||||||
| Cash and cash equivalents [abstract] | ||||||
| Cash and cash equivalents |
55,479,000
EUR
|
44,376,000
EUR
|
37,382,000
EUR
|
19,573,000
EUR
|
15,935,000
EUR
|
3,754,000
EUR
|
| Non-current assets or disposal groups classified as held for sale or as held for distribution to owners [abstract] | ||||||
| Non-current assets or disposal groups classified as held for sale |
588,000
EUR
|
588,000
EUR
|
796,000
EUR
|
796,000
EUR
|
— | — |
| Borrowings [abstract] | ||||||
| Non-current portion of non-current borrowings |
306,578,000
EUR
|
306,578,000
EUR
|
236,683,000
EUR
|
236,683,000
EUR
|
— | — |
| Current borrowings and current portion of non-current borrowings [abstract] | ||||||
| Current borrowings and current portion of non-current borrowings |
30,598,000
EUR
|
30,598,000
EUR
|
132,757,000
EUR
|
132,757,000
EUR
|
— | — |
| Non-current portion of non-current borrowings, by type [abstract] | ||||||
| Current borrowings and current portion of non-current borrowings, by type [abstract] | ||||||
| Trade and other non-current payables [abstract] | ||||||
| Non-current accruals and non-current deferred income including non-current contract liabilities [abstract] | ||||||
| Non-current deferred income including non-current contract liabilities [abstract] | ||||||
| Non-current contract liabilities [abstract] | ||||||
| Non-current contract liabilities |
19,730,000
EUR
|
19,237,000
EUR
|
17,072,000
EUR
|
16,425,000
EUR
|
— | — |
| Accruals classified as non-current |
8,916,000
EUR
|
426,000
EUR
|
5,810,000
EUR
|
666,000
EUR
|
— | — |
| Other non-current payables |
23,336,000
EUR
|
17,316,000
EUR
|
8,177,000
EUR
|
3,847,000
EUR
|
— | — |
| Trade and other current payables [abstract] | ||||||
| Current accruals and current deferred income including current contract liabilities [abstract] | ||||||
| Current deferred income including current contract liabilities [abstract] | ||||||
| Current contract liabilities [abstract] | ||||||
| Current contract liabilities |
11,907,000
EUR
|
5,779,000
EUR
|
10,275,000
EUR
|
5,602,000
EUR
|
— | — |
| Accruals classified as current |
34,309,000
EUR
|
29,052,000
EUR
|
35,691,000
EUR
|
30,161,000
EUR
|
— | — |
| Trade and other current payables |
123,746,000
EUR
|
108,222,000
EUR
|
123,915,000
EUR
|
99,300,000
EUR
|
— | — |
| Issued capital [abstract] | ||||||
| Issued capital |
272,721,000
EUR
|
272,721,000
EUR
|
272,721,000
EUR
|
272,721,000
EUR
|
— | — |
| Retained earnings [abstract] | ||||||
| Retained earnings, profit (loss) for reporting period |
47,065,000
EUR
|
23,864,000
EUR
|
37,506,000
EUR
|
20,793,000
EUR
|
— | — |
| Retained earnings, excluding profit (loss) for reporting period |
49,575,000
EUR
|
46,628,000
EUR
|
12,497,000
EUR
|
26,076,000
EUR
|
— | — |
| Retained earnings |
96,640,000
EUR
|
70,492,000
EUR
|
50,003,000
EUR
|
46,869,000
EUR
|
— | — |
| Accumulated other comprehensive income [abstract] | ||||||
| Reserve of exchange differences on translation |
52,000
EUR
|
0
EUR
|
18,000
EUR
|
0
EUR
|
— | — |
| Reserve of remeasurements of defined benefit plans |
1,429,000
EUR
|
1,214,000
EUR
|
1,155,000
EUR
|
897,000
EUR
|
— | — |
| Miscellaneous equity [abstract] | ||||||
| Capital redemption reserve |
4,065,000
EUR
|
4,065,000
EUR
|
4,065,000
EUR
|
4,065,000
EUR
|
— | — |
| Statutory reserve |
54,854,000
EUR
|
54,544,000
EUR
|
54,854,000
EUR
|
54,544,000
EUR
|
— | — |
| Capital reserve |
106,479,000
EUR
|
104,978,000
EUR
|
106,479,000
EUR
|
104,978,000
EUR
|
— | — |
| Net assets (liabilities) [abstract] | ||||||
| Assets |
1,317,866,000
EUR
|
1,250,315,000
EUR
|
1,275,338,000
EUR
|
1,223,290,000
EUR
|
— | — |
| Liabilities |
659,228,000
EUR
|
620,126,000
EUR
|
663,661,000
EUR
|
617,057,000
EUR
|
— | — |
| Net current assets (liabilities) [abstract] | ||||||
| Current assets |
273,861,000
EUR
|
264,566,000
EUR
|
243,822,000
EUR
|
225,060,000
EUR
|
— | — |
| Current liabilities |
210,437,000
EUR
|
185,163,000
EUR
|
313,464,000
EUR
|
280,347,000
EUR
|
— | — |
| Assets less current liabilities [abstract] |