Retirement Benefit Plans - Summary of Maturity Analysis of Undiscounted Pension Benefit (Detail) $ in Thousands, $ in Thousands |
Dec. 31, 2025
TWD ($)
|
Dec. 31, 2025
USD ($)
|
Dec. 31, 2024
TWD ($)
|
|---|---|---|---|
| Disclosure of defined benefit plans [line items] | |||
| Maturity analysis of undiscounted pension benefit | $ 16,825,960 | $ 536,371 | $ 13,127,807 |
| Less than 1 year [member] | |||
| Disclosure of defined benefit plans [line items] | |||
| Maturity analysis of undiscounted pension benefit | 760,181 | 24,233 | 677,634 |
| 1-5 years [member] | |||
| Disclosure of defined benefit plans [line items] | |||
| Maturity analysis of undiscounted pension benefit | 2,931,962 | 93,464 | 2,870,872 |
| More than 5 years [member] | |||
| Disclosure of defined benefit plans [line items] | |||
| Maturity analysis of undiscounted pension benefit | $ 13,133,817 | $ 418,674 | $ 9,579,301 |