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 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 | — | — | — | 
                                                2,184,465,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                2,066,210,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,889,078,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1,434,360,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                956,158,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | — | 
                                                -45,978,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                -17,165,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                153,890,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -711,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -402,104,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | — | — | — | 
                                                4,791,577,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                4,819,380,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,463,090,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,785,066,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2,723,140,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | — | — | 
                                                6,230,910,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                6,292,798,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,624,224,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                3,577,869,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                3,432,783,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | — | — | 
                                                305.48
                                                
                                             | — | — | — | — | 
                                                309.44
                                                
                                             | — | — | 
                                                222.36
                                                
                                             | — | — | — | 
                                                178.94
                                                
                                             | — | — | — | — | — | 
                                                174.96
                                                
                                             | 
| Basic earnings (loss) per share | — | — | — | 
                                                -1.77
                                                
                                             | — | — | — | — | — | — | 
                                                104.24
                                                
                                             | 
                                                9.07
                                                
                                             | — | — | — | — | — | 
                                                4.05
                                                
                                             | — | — | — | 
                                                -138.74
                                                
                                             | — | 
| Diluted earnings per share | — | — | — |  | — | — | — | — | — | — | 
                                                103.82
                                                
                                             | 
                                                9.02
                                                
                                             | — | — | — | — | — | 
                                                4.03
                                                
                                             | — | — | — |  | — | 
| Equity-to-asset ratio | — | — | — | — | 
                                                0.769
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.766
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.749
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.770
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.784
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                0.392
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.045
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.023
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                3.35
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                88.22
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                124.83
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Number of employees | — | 
                                                16
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                118
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                99
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                102
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                103
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                85
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                75
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                130
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                53
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                116
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                138
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                62
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | — | 
                                                8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                45
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                19
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                37
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                42
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                13
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                12
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                38
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                10
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                35
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                29
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Revenue | 
                                                4,739,514,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                7,906,739,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                6,571,001,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,385,083,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                3,695,806,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Profit (loss) before tax | 
                                                287,471,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                1,875,084,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1,059,796,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -84,062,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -1,707,738,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Profit (loss), attributable to owners of parent | 
                                                226,603,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                1,818,596,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                764,292,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,626,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -1,634,914,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Comprehensive income, attributable to owners of parent | 
                                                167,452,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                2,081,078,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                926,946,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -60,888,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -1,844,582,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Equity attributable to owners of parent | — | — | 
                                                6,137,394,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                5,947,742,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                3,866,663,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,793,822,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,825,985,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Total assets | — | — | 
                                                8,490,467,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                8,471,270,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                7,314,533,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                5,767,772,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,385,202,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Owners' equity per share | — | — | 
                                                391.28
                                                
                                             | — | — | — | — | 
                                                381.89
                                                
                                             | — | — | — | — | — | 
                                                248.27
                                                
                                             | — | — | — | — | 
                                                181.56
                                                
                                             | 
                                                183.70
                                                
                                             | — | — | — | 
| Basic earnings (loss) per share | 
                                                14.47
                                                
                                             | — | — | — | — | — | — | — | 
                                                116.77
                                                
                                             | — | — | — | — | — | 
                                                49.22
                                                
                                             | 
                                                1.21
                                                
                                             | — | — | — | — | 
                                                -106.35
                                                
                                             | — | — | 
| Diluted earnings (loss) per share | 
                                                14.46
                                                
                                             | — | — | — | — | — | — | — | 
                                                116.30
                                                
                                             | — | — | — | — | — | 
                                                48.97
                                                
                                             | 
                                                1.21
                                                
                                             | — | — | — | — |  | — | — | 
| Ratio of owners' equity to gross assets | — | — | 
                                                0.723
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.702
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.529
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.484
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.525
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
| Rate of return on equity | 
                                                0.038
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                0.371
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.230
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.007
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Price-earnings ratio | 
                                                21.14
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                2.99
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                16.25
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                417.95
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Cash flows from (used in) operating activities | 
                                                698,108,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                793,560,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                678,714,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                466,430,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -379,588,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from (used in) investing activities | 
                                                -716,182,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                -291,056,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -536,012,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -342,142,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -538,085,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from (used in) financing activities | 
                                                -154,515,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                375,775,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                307,868,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                255,899,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                648,236,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | — | 
                                                3,495,505,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                3,596,782,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2,598,630,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,067,077,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,700,469,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — |