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Investment in Associates - Details of Investment in Associates (Detail) $ in Thousands, $ in Thousands |  | 12 Months Ended |
--- | --- | --- | ---
Apr. 08, 2019 | Dec. 31, 2019 TWD ($) | Dec. 31, 2018 TWD ($) | Dec. 31, 2019 USD ($)
Disclosure of associates [line items] |  |  |  |
Carrying amount |  | $ 3,392,910 | $ 3,863,741 | $ 113,437
JMC ELECTRONICS CO., LTD. [member] |  |  |  |
Disclosure of associates [line items] |  |  |  |
Principal place of business |  | Kaohsiung, Taiwan |  |
Measurement method |  | Equity method |  |
Carrying amount |  | $ 249,793 | $ 406,792 |
Shareholding ratio | 10.00% | 10.00% | 19.10% |
Nature of relationship |  | Strategic Investee |  |
Unimos Shanghai [member] |  |  |  |
Disclosure of associates [line items] |  |  |  |
Principal place of business |  | Shanghai, PRC |  |
Measurement method |  | Equity method |  |
Carrying amount |  | $ 3,143,117 | $ 3,456,949 |
Shareholding ratio |  | 45.02% | 45.02% |
Nature of relationship |  | Strategic Investee |  |

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- Definition The country in which an associate of the entity is incorporated. [Refer: Associates [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 27 -IssueDate 2019-01-01 -Paragraph 16 -Subparagraph b -Clause ii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=27&code=ifrs-tx-2019-en-r&anchor=para_16_b_ii&doctype=Standard -URIDate 2019-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 27 -IssueDate 2019-01-01 -Paragraph 17 -Subparagraph b -Clause ii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=27&code=ifrs-tx-2019-en-r&anchor=para_17_b_ii&doctype=Standard -URIDate 2019-03-27 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2019-01-01 -Paragraph 21 -Subparagraph a -Clause iii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2019-en-r&anchor=para_21_a_iii&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The description of the nature of the entity's relationship with an associate (for example, describing the nature of the activities of the associate and whether they are strategic to the entity's activities). [Refer: Associates [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2019-01-01 -Paragraph 21 -Subparagraph a -Clause ii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2019-en-r&anchor=para_21_a_ii&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The description of whether the investment in an associate is measured using the equity method or at fair value. [Refer: At fair value [member]; Associates [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2019-01-01 -Paragraph 21 -Subparagraph b -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2019-en-r&anchor=para_21_b_i&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table. + References No definition available. + Details
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- Definition The amount of investments in associates accounted for using the equity method. [Refer: Associates [member]; Investments accounted for using equity method] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 55 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_55&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The proportion of ownership interest in an associate attributable to the entity. [Refer: Associates [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 27 -IssueDate 2019-01-01 -Paragraph 17 -Subparagraph b -Clause iii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=27&code=ifrs-tx-2019-en-r&anchor=para_17_b_iii&doctype=Standard -URIDate 2019-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 27 -IssueDate 2019-01-01 -Paragraph 16 -Subparagraph b -Clause iii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=27&code=ifrs-tx-2019-en-r&anchor=para_16_b_iii&doctype=Standard -URIDate 2019-03-27 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2019-01-01 -Paragraph 21 -Subparagraph a -Clause iv -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2019-en-r&anchor=para_21_a_iv&doctype=Standard -URIDate 2019-03-27 + Details
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- Details
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