Quarterly Consolidated Statement Of Cash Flows
| Concept | 2024-01-01 to 2024-06-30 | As at 2024-06-30 | As at 2023-12-31 | 2023-01-01 to 2023-06-30 | As at 2023-06-30 | As at 2022-12-31 | 
|---|---|---|---|---|---|---|
| Quarterly consolidated statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Subtotal | 
                                                84,217,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                117,926,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | 
                                                -13,218,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,921,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                28,931,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -18,449,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | ||||||
| Purchase of property, plant and equipment | 
                                                -18,330,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -9,208,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of property, plant and equipment | 
                                                135,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of investment securities | 
                                                -10,026,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of shares of subsidiaries resulting in change in scope of consolidation | 
                                                -1,892,371,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                -1,946,310,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -37,717,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | ||||||
| Repayments of long-term borrowings | 
                                                -128,940,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -66,418,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from issuance of shares | 
                                                300,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,900,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                2,059,418,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                208,740,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Effect of exchange rate change on cash and cash equivalents | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                142,039,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                152,573,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                1,055,754,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                913,714,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                812,084,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                659,511,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |