Capital management - Additional Information (Detail) - EUR (€)  | 
6 Months Ended | 12 Months Ended | ||
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Jun. 30, 2022  | 
Jun. 30, 2021  | 
Dec. 31, 2021  | 
Dec. 31, 2020  | 
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| Capital commitments | € 0 | € 0 | ||
| EBITDA margin ratio | 5.63% | 12.92% | 3.77% | 25.84% | 
| EBITDA | € 7,000,000 | € 8,000,000 | € 3,600,000 | € 15,300,000 | 
| Interest coverage | 21.7 | 13.57 | 17.78 | 16.2 | 
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- Definition Earnings before interest, taxes, depreciation, and amortization. No definition available. 
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- Definition EBITDA margin ratio. No definition available. 
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- Definition Interest coverage. No definition available. 
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- Definition Text block. No definition available. 
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- Definition The amount of future capital expenditures that the entity is committed to make. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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