v3.26.1
Operating Segments Information - Summary of Segment Information (Detail)
$ in Thousands, $ in Thousands
 12 Months Ended
Dec. 31, 2025
TWD ($)
Dec. 31, 2025
USD ($)
Dec. 31, 2024
TWD ($)
Dec. 31, 2023
TWD ($)
Dec. 31, 2025
USD ($)
Disclosure of operating segments [line items]          
Operating revenue $ 645,387,710 $ 20,573,405 $ 595,409,585 $ 581,914,471  
Interest income 1,879,685 59,920 1,883,518 1,513,407  
Interest expense (7,478,400) (238,393) (6,747,843) (6,238,910)  
Depreciation and amortization (67,439,837) (2,149,819) (59,815,212) (58,101,863)  
Share of the profit or loss of associates and joint ventures 815,990 26,012 896,702 1,080,600  
Impairment loss (605,981) (19,317) (176,023) (146,570)  
Segment profit before income tax 51,303,096 1,635,419 41,733,373 42,611,823  
Expenditures for segment assets 171,616,529 5,470,721 96,207,546 48,758,649  
Investments accounted for using the equity method 25,030,827   20,423,340 19,678,314 $ 797,922
Contract assets 7,568,112   5,640,317 5,100,076 241,253
Packaging segment [member]          
Disclosure of operating segments [line items]          
Operating revenue 308,342,594 9,829,219 261,731,413 256,805,887  
Interest income 158,334 5,047 223,222 188,704  
Interest expense (3,247,286) (103,516) (2,701,084) (2,907,679)  
Depreciation and amortization (37,261,275) (1,187,800) (33,951,864) (34,110,372)  
Share of the profit or loss of associates and joint ventures 648,174 20,663 698,852 916,310  
Impairment loss (47,482) (1,514) (121,992) (81,133)  
Segment profit before income tax 31,039,237 989,456 28,948,970 25,405,636  
Expenditures for segment assets 113,391,501 3,614,648 58,566,380 27,881,152  
Investments accounted for using the equity method 19,312,606   15,422,237 15,159,266 615,639
Contract assets 6,067,444   4,337,297 4,066,174 193,415
Testing segment [member]          
Disclosure of operating segments [line items]          
Operating revenue 71,900,228 2,292,006 54,561,480 49,879,923  
Interest income 178,655 5,695 182,106 124,443  
Interest expense (1,199,998) (38,253) (766,292) (720,145)  
Depreciation and amortization (22,205,667) (707,863) (17,457,538) (16,173,653)  
Share of the profit or loss of associates and joint ventures 33,103 1,055 53,574 134,667  
Impairment loss (38,030) (1,212) (2,845) (65,437)  
Segment profit before income tax 15,124,700 482,139 10,616,147 9,369,875  
Expenditures for segment assets 51,649,837 1,646,472 31,397,079 13,664,416  
Investments accounted for using the equity method 3,355,902   2,618,682 2,338,125 106,978
Contract assets 1,500,668   1,303,020 1,033,902 47,838
EMS segment [member]          
Disclosure of operating segments [line items]          
Operating revenue 257,192,747 8,198,685 271,293,309 268,218,002  
Interest income 1,471,308 46,902 1,409,437 1,087,121  
Interest expense (1,931,523) (61,572) (2,062,626) (1,816,814)  
Depreciation and amortization (5,622,193) (179,222) (5,895,380) (5,335,496)  
Share of the profit or loss of associates and joint ventures 145,186 4,628 152,996 38,211  
Impairment loss (40,192) (1,281) (51,186)    
Segment profit before income tax 7,654,796 244,016 7,594,473 9,216,053  
Expenditures for segment assets 5,894,373 187,898 5,551,760 6,207,532  
Investments accounted for using the equity method 2,362,319   2,355,629 2,160,112 $ 75,305
All other segments [member]          
Disclosure of operating segments [line items]          
Operating revenue 7,952,141 253,495 7,823,383 7,010,659  
Interest income 71,388 2,276 68,753 113,139  
Interest expense (1,099,593) (35,052) (1,217,841) (794,272)  
Depreciation and amortization (2,350,702) (74,934) (2,510,430) (2,482,342)  
Share of the profit or loss of associates and joint ventures (10,473) (334) (8,720) (8,588)  
Impairment loss (480,277) (15,310)      
Segment profit before income tax (2,515,637) (80,192) (5,426,217) (1,379,741)  
Expenditures for segment assets 680,818 21,703 692,327 1,005,549  
Investments accounted for using the equity method     26,792 20,811  
Inter-group revenues [member] | Packaging segment [member]          
Disclosure of operating segments [line items]          
Operating revenue 5,671,362 180,789 5,829,221 4,550,622  
Inter-group revenues [member] | Testing segment [member]          
Disclosure of operating segments [line items]          
Operating revenue 557,926 17,785 420,691 447,279  
Inter-group revenues [member] | EMS segment [member]          
Disclosure of operating segments [line items]          
Operating revenue 31,708,367 1,010,786 35,110,458 26,639,833  
Inter-group revenues [member] | All other segments [member]          
Disclosure of operating segments [line items]          
Operating revenue 8,430,074 268,731 6,536,547 6,776,002  
Inter-group revenues [member] | Adjustments and Eliminations [member]          
Disclosure of operating segments [line items]          
Operating revenue (46,367,729) (1,478,091) (47,896,917) (38,413,736)  
Operating segment [member]          
Disclosure of operating segments [line items]          
Operating revenue 691,755,439 22,051,496 643,306,502 620,328,207  
Operating segment [member] | Packaging segment [member]          
Disclosure of operating segments [line items]          
Operating revenue 314,013,956 10,010,008 267,560,634 261,356,509  
Operating segment [member] | Testing segment [member]          
Disclosure of operating segments [line items]          
Operating revenue 72,458,154 2,309,791 54,982,171 50,327,202  
Operating segment [member] | EMS segment [member]          
Disclosure of operating segments [line items]          
Operating revenue 288,901,114 9,209,471 306,403,767 294,857,835  
Operating segment [member] | All other segments [member]          
Disclosure of operating segments [line items]          
Operating revenue $ 16,382,215 $ 522,226 $ 14,359,930 $ 13,786,661