Statement Of Cash Flows [Abstract]
| Concept | 
                                    
                                        2023-01-01 to 2023-12-31  | 
                            
                                
                                    
                                        As at 2023-12-31  | 
                            
                                
                                    
                                        As at 2022-12-31  | 
                            
                                
                                    
                                        2022-01-01 to 2022-12-31  | 
                            
                                
                                    
                                        As at 2021-12-31  | 
                            
                        
|---|---|---|---|---|---|
| Statement of cash flows [abstract] | |||||
| Cash flows from (used in) operating activities [abstract] | |||||
| Classes of cash payments from operating activities [abstract] | |||||
| Payments to suppliers for goods and services | 
                                        
                                             
                                                56,701,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                44,491,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Payments to and on behalf of employees | 
                                        
                                             
                                                9,345,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                6,487,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Other cash payments from operating activities | 
                                        
                                             
                                                3,547,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                2,858,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash flows from (used in) operating activities | 
                                        
                                             
                                                23,555,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                26,126,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash flows from (used in) investing activities [abstract] | |||||
| Other cash payments to acquire interests in joint ventures, classified as investing activities | 
                                        
                                             
                                                2,235,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash advances and loans made to other parties, classified as investing activities | 
                                        
                                             
                                                939,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                1,593,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash receipts from repayment of advances and loans made to other parties, classified as investing activities | 
                                        
                                             
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                1,502,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Interest received, classified as investing activities | 
                                        
                                             
                                                137,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                131,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash flows from (used in) investing activities | 
                                        
                                             
                                                27,572,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                10,005,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash flows from (used in) financing activities [abstract] | |||||
| Proceeds from issuing shares | 
                                        
                                             
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                16,000,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Payments of lease liabilities, classified as financing activities | 
                                        
                                             
                                                490,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Dividends paid, classified as financing activities | 
                                        
                                             
                                                12,937,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                10,152,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash flows from (used in) financing activities | 
                                        
                                             
                                                13,427,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                5,848,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Effect of exchange rate changes on cash and cash equivalents [abstract] | |||||
| Effect of exchange rate changes on cash and cash equivalents | 
                                        
                                             
                                                56,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                53,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Increase (decrease) in cash and cash equivalents after effect of exchange rate changes | 
                                        
                                             
                                                17,500,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                21,916,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash and cash equivalents | — | 
                                        
                                             
                                                26,742,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                44,242,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                22,326,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             
                                        
                                     |