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Financial Risk Management and Fair Values of Financial Instruments - Summary of Natures of Assets and Liabilities (Detail) - TWD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019
Disclosure of detailed information about financial instruments [Line Items] |  |
Financial assets at fair value through profit or loss | $ 63,488 | $ 11,038
Financial assets at fair value | 325,495 | 132,846
Foreign partnership interest [member] | Recurring fair value measurement [member] |  |
Disclosure of detailed information about financial instruments [Line Items] |  |
Financial assets at fair value through profit or loss | 10,368 | 11,038
Foreign unlisted stocks [member] | Recurring fair value measurement [member] |  |
Disclosure of detailed information about financial instruments [Line Items] |  |
Financial assets at fair value through other comprehensive income | 262,007 | 121,808
Listed stocks [member] | Recurring fair value measurement [member] |  |
Disclosure of detailed information about financial instruments [Line Items] |  |
Financial assets at fair value through profit or loss | 53,120 |
Level 1 [member] |  |
Disclosure of detailed information about financial instruments [Line Items] |  |
Financial assets at fair value | 53,120 |
Level 1 [member] | Listed stocks [member] | Recurring fair value measurement [member] |  |
Disclosure of detailed information about financial instruments [Line Items] |  |
Financial assets at fair value through profit or loss | 53,120 |
Level 3 [member] |  |
Disclosure of detailed information about financial instruments [Line Items] |  |
Financial assets at fair value | 272,375 | 132,846
Level 3 [member] | Foreign partnership interest [member] | Recurring fair value measurement [member] |  |
Disclosure of detailed information about financial instruments [Line Items] |  |
Financial assets at fair value through profit or loss | 10,368 | 11,038
Level 3 [member] | Foreign unlisted stocks [member] | Recurring fair value measurement [member] |  |
Disclosure of detailed information about financial instruments [Line Items] |  |
Financial assets at fair value through other comprehensive income | $ 262,007 | $ 121,808

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- Definition The amount of financial assets at fair value through other comprehensive income. [Refer: At fair value [member]; Financial assets; Other comprehensive income] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2020-01-01 -Paragraph 8 -Subparagraph h -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_8_h&doctype=Standard -URIDate 2020-01-01 + Details
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- Definition The amount of financial assets that are measured at fair value and for which gains (losses) are recognised in profit or loss. A financial asset shall be measured at fair value through profit or loss unless it is measured at amortised cost or at fair value through other comprehensive income. A gain (loss) on a financial asset measured at fair value shall be recognised in profit or loss unless it is part of a hedging relationship, it is an investment in an equity instrument for which the entity has elected to present gains and losses in other comprehensive income or it is a financial asset measured at fair value through other comprehensive income. [Refer: At fair value [member]; Financial assets] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2020-01-01 -Paragraph 8 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_8_a&doctype=Standard -URIDate 2020-01-01 + Details
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