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Other gains and losses - Summary of Other gains and losses (Details) $ in Thousands, $ in Thousands | 12 Months Ended
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Dec. 31, 2020 TWD ($) | Dec. 31, 2020 USD ($) | Dec. 31, 2019 TWD ($) | Dec. 31, 2018 TWD ($)
Disclosure of Other gains and losses [Abstract] |  |  |  |
Foreign exchange gains (losses), net | $ (355,255) |  | $ (154,993) | $ 93,104
Reimbursement of ADSs service charge | 2,101 |  | 4,292 | 13,269
Gain on valuation of financial assets at fair value through profit or loss | 24,015 |  | 1,317 | 1,485
Others | 5,872 |  | 970 | 6,851
Total | $ (323,267) | $ (11,512) | $ (148,414) | $ 114,709

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- Definition The amount of exchange differences recognised in profit or loss that arise from foreign currency transactions, excluding those arising on financial instruments measured at fair value through profit or loss in accordance with IFRS 9. [Refer: At fair value [member]; Financial instruments, class [member]] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Section A Statement of cash flows for an entity other than a financial institution -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&doctype=Illustrative%20Examples&dita_xref=IAS07_IE_A_TI -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 21 -IssueDate 2020-01-01 -Paragraph 52 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=21&code=ifrs-tx-2020-en-r&anchor=para_52_a&doctype=Standard -URIDate 2020-01-01 + Details
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- Definition The gains (losses) on financial assets at fair value through profit or loss. [Refer: Financial assets at fair value through profit or loss] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -Subparagraph a -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20_a_i&doctype=Standard -URIDate 2020-01-01 + Details
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- Definition The gains (losses) that the entity does not separately disclose in the same statement or note. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 102 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_102&doctype=Standard -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 103 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_103&doctype=Standard -URIDate 2020-01-01 + Details
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- Definition Disclosure of Other gains and losses. + References No definition available. + Details
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- Definition Reimbursement of American depositary shares charge. + References No definition available. + Details
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