Income Tax - Summary of Income Tax Recognized in Other Comprehensive Income (Detail) $ in Thousands, $ in Thousands |
12 Months Ended | |||
|---|---|---|---|---|
|
Dec. 31, 2025
TWD ($)
|
Dec. 31, 2025
USD ($)
|
Dec. 31, 2024
TWD ($)
|
Dec. 31, 2023
TWD ($)
|
|
| Income tax relating to components of other comprehensive income [abstract] | ||||
| Related to remeasurement of defined benefit plans | $ 249,889 | $ 7,966 | $ (62,184) | $ (2,214) |
| Unrealized loss on equity instruments at fair value through other comprehensive income | (383,009) | (12,210) | (22,288) | (262,404) |
| Unrealized gain (loss) on debt instruments at fair value through other comprehensive income | 2,379 | 76 | 2,315 | (5,792) |
| Income tax recognized in other comprehensive income | $ (130,741) | $ (4,168) | $ (82,157) | $ (270,410) |