Statement Of Changes In Equity [Abstract]
| Concept | 2021-01-01 to 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | 2021-01-01 to 2021-12-31 | 2021-01-01 to 2021-12-31 | As at 2021-12-31 | 2021-01-01 to 2021-12-31 | As at 2021-12-31 | 2021-01-01 to 2021-12-31 | 2021-01-01 to 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | 2021-01-01 to 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | 2021-01-01 to 2021-12-31 | 2021-01-01 to 2021-12-31 | 2020-01-01 to 2020-12-31 | As at 2020-12-31 | As at 2020-12-31 | As at 2020-12-31 | As at 2020-12-31 | 2020-01-01 to 2020-12-31 | 2020-01-01 to 2020-12-31 | As at 2020-12-31 | As at 2020-12-31 | As at 2020-12-31 | 2020-01-01 to 2020-12-31 | 2020-01-01 to 2020-12-31 | As at 2020-12-31 | 2020-01-01 to 2020-12-31 | 2020-01-01 to 2020-12-31 | As at 2020-12-31 | 2020-01-01 to 2020-12-31 | 2020-01-01 to 2020-12-31 | As at 2019-12-31 | As at 2019-12-31 | As at 2019-12-31 | As at 2019-12-31 | As at 2019-12-31 | As at 2019-12-31 | As at 2019-12-31 | As at 2019-12-31 | As at 2019-12-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of changes in equity [abstract] | |||||||||||||||||||||||||||||||||||||||||||||
| Statement of changes in equity [line items] | |||||||||||||||||||||||||||||||||||||||||||||
| Equity | — | 
                                                8 328
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                4,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | 
                                                10 567
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
                                                230,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | 
                                                10 435
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                1 193
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
                                                5,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                675,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                132,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | — | 
                                                1 218
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                130,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                3 013
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                675,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | 
                                                21,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                425,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                1 193
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | 
                                                3 143
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | 
                                                1 959
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | 
                                                3 151
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                90,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                616,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                9,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                1 193
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                3 241
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                1 536
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                2 194
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                675,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
| Changes in equity [abstract] | |||||||||||||||||||||||||||||||||||||||||||||
| Comprehensive income [abstract] | |||||||||||||||||||||||||||||||||||||||||||||
| Profit (loss) | 
                                                6,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                8 230
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | — | 
                                                8 224
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                8 230
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                177,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | — | — | 
                                                128,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | — | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                49,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                128,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
| Other comprehensive income | 
                                                8,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | 
                                                6,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                698,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
                                                26,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                678,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | — | 
                                                706,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                275,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | — | — | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                235,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | — | 
                                                1,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
                                                30,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                9,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                266,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
| Comprehensive income | 
                                                2,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | 
                                                6,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                8 928
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
                                                26,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                678,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | — | 
                                                8 930
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                8 230
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                98,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | — | — | 
                                                128,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                235,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | — | 
                                                1,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
                                                30,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                40,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                138,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
| Increase (decrease) through other changes, equity | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | — | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | — | — | 
                                                2 407
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                2 407
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |