Statement Of Cash Flows [Abstract]
| Concept | As at 2023-12-31 | 2023-01-01 to 2023-12-31 | 2022-01-01 to 2022-12-31 | As at 2022-12-31 | 
|---|---|---|---|---|
| Statement of cash flows [abstract] | ||||
| Cash flows from (used in) operating activities [abstract] | ||||
| Classes of cash receipts from operating activities [abstract] | ||||
| Receipts from sales of goods and rendering of services | — | 
                                                124,726,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                143,995,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Classes of cash payments from operating activities [abstract] | ||||
| Payments to suppliers for goods and services | — | 
                                                66,292,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                66,900,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Payments to and on behalf of employees | — | 
                                                35,886,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                33,460,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Income taxes paid (refund), classified as operating activities | — | 
                                                938,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                956,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Other inflows (outflows) of cash, classified as operating activities | — | 
                                                837,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                315,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Cash flows from (used in) operating activities | — | 
                                                25,314,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                46,917,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Cash flows from (used in) investing activities [abstract] | ||||
| Proceeds from sales of property, plant and equipment, classified as investing activities | — | 
                                                77,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                204,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Purchase of property, plant and equipment, classified as investing activities | — | 
                                                23,306,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                20,480,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Proceeds from government grants, classified as investing activities | — | 
                                                64,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Interest received, classified as investing activities | — | 
                                                1,154,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                144,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Cash flows from (used in) investing activities | — | 
                                                21,490,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                20,160,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Cash flows from (used in) financing activities [abstract] | ||||
| Proceeds from borrowings, classified as financing activities | — | 
                                                9,752,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                9,767,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Repayments of borrowings, classified as financing activities | — | 
                                                933,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                4,925,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Payments of lease liabilities, classified as financing activities | — | 
                                                278,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                324,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Dividends paid, classified as financing activities | — | 
                                                451,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                439,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Cash flows from (used in) financing activities | — | 
                                                7,805,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                3,921,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Increase (decrease) in cash and cash equivalents before effect of exchange rate changes | — | 
                                                11,629,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                30,678,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Effect of exchange rate changes on cash and cash equivalents [abstract] | ||||
| Effect of exchange rate changes on cash and cash equivalents | — | 
                                                45,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                181,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | 
                                                56,938,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | 
                                                45,374,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             |