Key Financial Data Of Reporting Company
| Concept | As at 2024-01-31 | 2023-02-01 to 2024-01-31 | As at 2023-01-31 | 2022-02-01 to 2023-01-31 | As at 2022-01-31 | 2021-02-01 to 2022-01-31 | As at 2021-01-31 | 2020-02-01 to 2021-01-31 | 2019-02-01 to 2020-01-31 | As at 2020-01-31 | 
|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||||||
| Business results of reporting company | ||||||||||
| Net sales | — | 
                                                10,110,524,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,242,360,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                8,102,991,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                7,174,725,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,002,175,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | 
                                                1,532,616,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,203,054,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,032,341,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                910,457,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                893,656,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) | — | 
                                                1,051,817,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                895,148,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                728,785,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                628,561,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                613,377,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Equity in earnings (losses) of affiliates if equity method is applied | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Share capital | 
                                                238,284,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                238,284,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                238,284,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                238,284,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                238,284,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total number of issued shares | 
                                                10,627,920
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                10,627,920
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                10,627,920
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                10,627,920
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | 
                                                10,627,920
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Net assets | 
                                                4,271,153,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,047,958,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,582,246,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,123,182,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,728,380,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | 
                                                6,114,087,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,673,188,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,088,983,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,432,313,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,801,139,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | 
                                                401.97
                                                
                                             | — | 
                                                380.96
                                                
                                             | — | 
                                                337.14
                                                
                                             | — | 
                                                293.93
                                                
                                             | — | — | 
                                                256.77
                                                
                                             | 
| Dividend paid per share | — | 
                                                75.00
                                                
                                             | — | 
                                                60.00
                                                
                                             | — | 
                                                34.50
                                                
                                             | — | 
                                                23.00
                                                
                                             | 
                                                20.50
                                                
                                             | — | 
| Interim dividend paid per share | — | 
                                                37.50
                                                
                                             | — | 
                                                20.00
                                                
                                             | — | 
                                                14.00
                                                
                                             | — | 
                                                11.50
                                                
                                             | 
                                                10.00
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                98.99
                                                
                                             | — | 
                                                84.24
                                                
                                             | — | 
                                                68.59
                                                
                                             | — | 
                                                59.16
                                                
                                             | 
                                                57.73
                                                
                                             | — | 
| Diluted earnings per share | — |  | — |  | — |  | — |  |  | — | 
| Equity-to-asset ratio | 
                                                0.699
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.714
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.704
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.705
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.718
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | 
                                                0.253
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.235
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.217
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.215
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.242
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | 
                                                22.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                11.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                12.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                14.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                14.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Payout ratio | — | 
                                                0.758
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.712
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.503
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.389
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.355
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                1,126,248,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                872,598,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                770,935,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                899,285,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                591,153,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | 
                                                -5,975,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -24,085,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                33,643,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -30,979,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -42,723,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | 
                                                -818,544,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -426,831,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -270,037,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -232,089,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -215,920,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | 
                                                4,277,610,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,975,881,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,554,199,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,019,657,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,383,441,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Number of employees | 
                                                1,321
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,276
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,180
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,079
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1,002
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total shareholder return | 
                                                2.629
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.231
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.027
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.983
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.918
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total return on share price index | 
                                                1.839
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.388
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.297
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.212
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1.102
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |