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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, 2021 $ / shares | Dec. 31, 2021 TWD ($) $ / shares shares | Dec. 31, 2020 TWD ($) $ / shares shares | Dec. 31, 2019 TWD ($) $ / shares shares
Basic earnings per share, amount after tax |  |  |  |
Equity holders of the Company - Amount after tax | $ |  | $ 4,937,267 | $ 2,378,978 | $ 2,508,574
Diluted earnings per share, amount after tax |  |  |  |
Equity holders of the Company - Amount after tax | $ |  | $ 4,937,267 | $ 2,378,978 | $ 2,508,574
Weighted average number of ordinary shares outstanding |  | 727,240 | 727,240 | 727,111
Diluted earnings per share, weighted-average number of ordinary shares outstanding |  |  |  |
Employees' compensation |  | 15,618 | 9,668 | 9,879
Restricted shares |  |  |  | 126
Weighted average number of ordinary shares outstanding |  | 742,858 | 736,908 | 737,116
Ordinary shares [member] |  |  |  |
Basic earnings per share |  |  |  |
Equity holders of the Company - Earnings per share | (per share) | $ 0.24 | $ 6.79 | $ 3.27 | $ 3.45
Diluted earnings per share |  |  |  |
Equity holders of the Company - Earnings per share | (per share) | $ 0.24 | $ 6.65 | $ 3.23 | $ 3.40

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- Definition The weighted average number of ordinary shares outstanding plus the weighted average number of ordinary shares that would be issued on the conversion of all the dilutive potential ordinary shares into ordinary shares. [Refer: Ordinary shares [member]; Weighted average [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 33 -IssueDate 2021-01-01 -Paragraph 70 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=33&code=ifrs-tx-2021-en-r&anchor=para_70_b&doctype=Standard -URIDate 2021-03-24 + 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). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 33 -IssueDate 2021-01-01 -Paragraph 66 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=33&code=ifrs-tx-2021-en-r&anchor=para_66&doctype=Standard -URIDate 2021-03-24 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 33 -IssueDate 2021-01-01 -Paragraph 67 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=33&code=ifrs-tx-2021-en-r&anchor=para_67&doctype=Standard -URIDate 2021-03-24 + 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 2021-01-01 -Paragraph 66 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=33&code=ifrs-tx-2021-en-r&anchor=para_66&doctype=Standard -URIDate 2021-03-24 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 33 -IssueDate 2021-01-01 -Paragraph 67 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=33&code=ifrs-tx-2021-en-r&anchor=para_67&doctype=Standard -URIDate 2021-03-24 + Details
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