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Earnings Per Share - Income and Share Data Used in Basic and Diluted EPS Computations (Detail) $ / shares in Units, shares in Thousands, $ in Thousands | 12 Months Ended
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Dec. 31, 2024 $ / shares | Dec. 31, 2024 TWD ($) $ / shares shares | Dec. 31, 2023 TWD ($) $ / shares shares | Dec. 31, 2022 TWD ($) $ / shares shares
Basic earnings per share, amount after tax |  |  |  |
Equity holders of the Company - Amount after tax | $ |  | $ 1,439,536 | $ 1,967,565 | $ 3,439,697
Diluted earnings per share, amount after tax |  |  |  |
Equity holders of the Company - Amount after tax | $ |  | $ 1,439,536 | $ 1,967,565 | $ 3,439,697
Weighted average number of ordinary shares outstanding |  | 727,240 | 727,240 | 727,240
Diluted earnings per share, weighted-average number of ordinary shares outstanding |  |  |  |
Employees' compensation |  | 6,772 | 7,698 | 15,406
Weighted average number of ordinary shares outstanding |  | 734,012 | 734,938 | 742,646
Ordinary shares [member] |  |  |  |
Basic earnings per share |  |  |  |
Equity holders of the Company - Earnings per share | (per share) | $ 0.06 | $ 1.98 | $ 2.71 | $ 4.73
Diluted earnings per share |  |  |  |
Diluted earnings (loss) per share | (per share) | $ 0.06 | $ 1.96 | $ 2.68 | $ 4.63

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- Definition The amount of profit (loss) attributable to ordinary equity holders of the parent entity (the numerator) divided by the weighted average number of ordinary shares outstanding during the period (the denominator). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 33 -IssueDate 2024-01-01 -Paragraph 66 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=33&code=ifrs-tx-2024-en-r&anchor=para_66&doctype=Standard -URIDate 2024-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 33 -IssueDate 2024-01-01 -Paragraph 67 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=33&code=ifrs-tx-2024-en-r&anchor=para_67&doctype=Standard -URIDate 2024-03-27 + Details
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- Definition The amount of profit (loss) attributable to ordinary equity holders of the parent entity (the numerator), divided by the weighted average number of ordinary shares outstanding during the period (the denominator), both adjusted for the effects of all dilutive potential ordinary shares. [Refer: Ordinary shares [member]; Weighted average [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 33 -IssueDate 2024-01-01 -Paragraph 66 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=33&code=ifrs-tx-2024-en-r&anchor=para_66&doctype=Standard -URIDate 2024-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 33 -IssueDate 2024-01-01 -Paragraph 67 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=33&code=ifrs-tx-2024-en-r&anchor=para_67&doctype=Standard -URIDate 2024-03-27 + Details
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