Key Financial Data Of Reporting Company
| Concept | 2022-10-21 to 2023-10-20 | As at 2023-10-20 | As at 2023-10-20 | 2022-10-21 to 2023-10-20 | As at 2023-10-20 | As at 2023-10-20 | As at 2023-10-20 | As at 2023-10-20 | As at 2023-10-20 | As at 2023-10-20 | As at 2022-10-20 | As at 2022-10-20 | 2021-10-21 to 2022-10-20 | 2021-10-21 to 2022-10-20 | 2020-10-21 to 2021-10-20 | 2020-10-21 to 2021-10-20 | As at 2021-10-20 | As at 2021-10-20 | 2019-10-21 to 2020-10-20 | As at 2020-10-20 | 2019-10-21 to 2020-10-20 | As at 2020-10-20 | 2018-10-21 to 2019-10-20 | As at 2019-10-20 | As at 2019-10-20 | 2018-10-21 to 2019-10-20 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||||||||||||||||||||||
| Business results of reporting company | ||||||||||||||||||||||||||
| Net sales | 
                                                2,781,270,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,695,536,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                2,701,664,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,668,167,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,545,269,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,516,486,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,838,291,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,725,786,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | 
                                                185,484,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                152,466,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                137,884,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                139,291,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                36,689,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                42,098,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                265,994,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                268,515,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) | — | — | — | 
                                                147,437,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                94,527,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                22,553,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                179,324,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                191,611,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Equity in earnings (losses) of affiliates if equity method is applied | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share capital | — | — | — | — | 
                                                479,885,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                479,885,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                479,885,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                479,885,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                479,885,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total number of issued shares | — | — | — | — | 
                                                5,969,024
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                5,969,024
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | — | 
                                                5,969,024
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                5,969,024
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | 
                                                5,969,024
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | 
| Net assets | — | — | — | — | 
                                                2,994,873,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                3,026,892,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,855,784,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,849,684,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,655,840,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,647,286,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,642,848,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,502,820,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | — | — | — | — | 
                                                5,927,125,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                5,982,973,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,766,254,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,752,256,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                5,452,888,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,437,452,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,399,797,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,457,406,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets per share | — | — | — | — | 
                                                534.76
                                                
                                             | — | — | — | — | 
                                                540.47
                                                
                                             | 
                                                509.92
                                                
                                             | 
                                                508.83
                                                
                                             | — | — | — | — | 
                                                474.22
                                                
                                             | 
                                                472.69
                                                
                                             | — | 
                                                471.90
                                                
                                             | — |  | — | 
                                                446.90
                                                
                                             |  | — | 
| Dividend paid per share | — | — | — | 
                                                5.00
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                5.00
                                                
                                             | — | 
                                                5.00
                                                
                                             | — | — | — | — | 
                                                5.00
                                                
                                             | — | — | — | — | 
                                                5.00
                                                
                                             | 
| Interim dividend paid per share | — | — | — |  | — | — | — | — | — | — | — | — | — |  | — |  | — | — | — | — |  | — | — | — | — |  | 
| Basic earnings (loss) per share | 
                                                30.95
                                                
                                             | — | — | 
                                                26.33
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                16.17
                                                
                                             | 
                                                16.88
                                                
                                             | 
                                                5.56
                                                
                                             | 
                                                4.03
                                                
                                             | — | — |  | — | 
                                                32.02
                                                
                                             | — |  | — | — | 
                                                34.21
                                                
                                             | 
| Diluted earnings per share |  | — | — |  | — | — | — | — | — | — | — | — |  |  |  |  | — | — |  | — |  | — |  | — | — |  | 
| Equity-to-asset ratio | — | — | — | — | 
                                                0.505
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.506
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.495
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.495
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.487
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.487
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.489
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.459
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Rate of return on equity | 
                                                0.057
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.049
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                0.033
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.034
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.012
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.009
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.070
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.079
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Price-earnings ratio | 
                                                10.69
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                12.57
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                16.82
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                16.12
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                63.15
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                87.16
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                10.12
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                10.26
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Payout ratio | — | — | — | 
                                                0.190
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                0.296
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.242
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.156
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.146
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | 
                                                56,144,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                -53,031,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                311,409,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                45,790,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                474,411,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | 
                                                -68,836,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                -232,017,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -154,303,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -43,474,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -26,243,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | 
                                                -22,469,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                180,232,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -43,396,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -288,418,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -88,181,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                137,125,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                172,286,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                277,102,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                163,393,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                449,495,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Number of employees | — | 
                                                156
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                28
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                177
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                28
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                149
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                184
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                187
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                181
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                188
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                181
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                170
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                164
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Total shareholder return | — | — | — | — | 
                                                0.922
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                0.912
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1.137
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.040
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.107
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Total return on share price index | — | — | — | — | 
                                                1.506
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                1.233
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1.284
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.008
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.982
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — |