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Fair Value Information - Additional Information (Detail) - TWD ($) | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Disclosure Of Fair Value Measurement Of Financial Instruments [Abstract] |  |  |
Transfer between Level 1 and 2, assets | $ 0 | $ 0 | $ 0
Transfer between Level 2 and 1, assets | 0 | 0 | 0
Transfer between Level 1 and 2, liabilities | 0 | 0 | 0
Transfer between Level 2 and 1, liabilities | $ 0 | $ 0 | $ 0

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- Definition Disclosure of fair value measurement of financial instruments. + References No definition available. + Details
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- Definition The amount of transfers out of Level 1 and into Level 2 of the fair value hierarchy of assets held at the end of the reporting period. [Refer: Level 1 of fair value hierarchy [member]; Level 2 of fair value hierarchy [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2020-01-01 -Paragraph 93 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_93_c&doctype=Standard -URIDate 2020-01-01 + Details
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- Definition The amount of transfers out of Level 1 and into Level 2 of the fair value hierarchy of liabilities held at the end of the reporting period. [Refer: Level 1 of fair value hierarchy [member]; Level 2 of fair value hierarchy [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2020-01-01 -Paragraph 93 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_93_c&doctype=Standard -URIDate 2020-01-01 + Details
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- Definition The amount of transfers out of Level 2 and into Level 1 of the fair value hierarchy of assets held at the end of the reporting period. [Refer: Level 1 of fair value hierarchy [member]; Level 2 of fair value hierarchy [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2020-01-01 -Paragraph 93 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2020-en-r&anchor=para_93_c&doctype=Standard -URIDate 2020-01-01 + Details
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