Key Financial Data Of Group
| Concept | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2022-12-31 | 2022-01-01 to 2022-12-31 | As at 2022-12-31 | 2022-01-01 to 2022-12-31 | 2021-01-01 to 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | 2021-01-01 to 2021-12-31 | 2020-01-01 to 2020-12-31 | As at 2020-12-31 | 2020-01-01 to 2020-12-31 | As at 2020-12-31 | As at 2019-12-31 | 2019-01-01 to 2019-12-31 | 2019-01-01 to 2019-12-31 | As at 2019-12-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of group | |||||||||||||||||||||||||||
| Business results of group | |||||||||||||||||||||||||||
| Net sales | 
                                                9,722,408,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,898,477,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                9,658,439,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,731,146,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,653,073,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,371,262,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,900,357,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,443,051,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                10,665,086,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,882,885,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                1,467,465,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,091,167,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                1,568,260,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,013,014,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                905,339,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,264,768,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                968,598,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                947,197,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,554,771,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,022,600,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | 
                                                998,751,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
                                                1,006,100,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                828,876,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                693,088,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                993,447,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Comprehensive income | 
                                                1,024,048,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
                                                1,026,263,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                836,932,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                682,108,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                994,907,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net assets | — | — | 
                                                8,291,905,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                8,824,702,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                7,690,877,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                8,245,077,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,735,252,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,080,886,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,263,216,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,585,024,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,284,899,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                6,751,895,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | 
                                                10,767,513,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,895,880,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                9,728,111,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,130,168,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,732,740,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,398,997,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,167,585,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                8,321,108,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,892,303,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,844,648,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | 
                                                1,215.83
                                                
                                             | — | 
                                                1,293.95
                                                
                                             | — | — | — | — | — | — | 
                                                1,127.68
                                                
                                             | — | 
                                                1,208.94
                                                
                                             | — | — | 
                                                1,134.17
                                                
                                             | 
                                                1,038.22
                                                
                                             | — | — | 
                                                1,064.95
                                                
                                             | — | 
                                                965.51
                                                
                                             | 
                                                921.50
                                                
                                             | — | — | 
                                                989.97
                                                
                                             | 
| Basic earnings (loss) per share | 
                                                146.44
                                                
                                             | — | — | 
                                                143.85
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                147.51
                                                
                                             | — | 
                                                133.02
                                                
                                             | 
                                                118.05
                                                
                                             | — | — | 
                                                121.53
                                                
                                             | 
                                                101.62
                                                
                                             | — | 
                                                132.58
                                                
                                             | — | — | 
                                                145.66
                                                
                                             | 
                                                130.34
                                                
                                             | — | 
| Diluted earnings per share |  | — | — |  | — | — | — | — | — | — | — | — |  | — |  |  | — | — |  |  | — |  | — | — |  |  | — | 
| Equity-to-asset ratio | — | — | 
                                                0.770
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.892
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                0.791
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.903
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.886
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.753
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.889
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.791
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.707
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.861
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | 
                                                0.125
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.115
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                0.136
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.114
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.107
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.121
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.108
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.129
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.167
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.138
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | 
                                                11.55
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                11.75
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                12.30
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                13.64
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                13.70
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                13.31
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                12.91
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                9.89
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                11.14
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                12.45
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | 
                                                716,129,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
                                                1,630,810,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                568,302,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,040,078,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,100,202,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                -68,903,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
                                                -106,180,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                211,821,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -515,749,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -663,092,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                7,495,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
                                                -895,810,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -61,163,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -561,086,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -333,702,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | — | 
                                                3,762,196,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                3,103,171,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2,470,641,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,750,672,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,786,588,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Number of employees | — | 
                                                27
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                693
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                288
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                280
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                86
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                40
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                300
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                221
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                27
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                678
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                276
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                291
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                707
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                311
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                737
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                712
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                304
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                33
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                32
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                29
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                13
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                26
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                39
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |