Retirement Benefit Plans - Summary of Defined Benefit Plans Amounts Included in Consolidated Balance Sheets (Detail) $ in Thousands, $ in Thousands |
Dec. 31, 2023
TWD ($)
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Dec. 31, 2023
USD ($)
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Dec. 31, 2022
TWD ($)
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Dec. 31, 2022
USD ($)
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Dec. 31, 2021
TWD ($)
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Dec. 31, 2020
TWD ($)
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|---|---|---|---|---|---|---|
| Disclosure of net defined benefit liability (asset) [abstract] | ||||||
| Present value of the defined benefit obligation | $ 10,193,848 | $ 332,915 | $ 10,261,997 | |||
| Fair value of the plan assets | (6,617,058) | (216,103) | (6,477,877) | |||
| Present value of unfunded defined benefit obligation | 3,576,790 | 116,812 | 3,784,120 | $ 123,583 | $ 5,561,596 | $ 6,196,840 |
| Recorded under other payables | (20,281) | (662) | (88,983) | |||
| Recorded under other non-current assets | 181,844 | 5,939 | 248,843 | |||
| Net defined benefit liability | $ 3,738,353 | $ 122,089 | $ 3,943,980 |