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v3.21.1

Financial Statements Schedule: Valuation and Qualifying Accounts (Detail) - TWD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Allowance for Impairment of property, plant and equipment [member] |  |  |
Disclosure of details of valuation and qualifying accounts [Line Items] |  |  |
January 1 | $ 193,340 | $ 317,593 | $ 320,455
Additions charged to expense or deduction of revenue |  | 9,938 |
Deduction/Write-offs/Reversal | (11,338) | (134,191) | (2,862)
December 31 | 182,002 | 193,340 | 317,593
Allowance for Impairment of Obsolescence and Decline in Market Value of Inventories [Member] |  |  |
Disclosure of details of valuation and qualifying accounts [Line Items] |  |  |
January 1 | 63,498 | 36,157 | 53,714
Additions charged to expense or deduction of revenue | 16,317 | 27,341 |
Deduction/Write-offs/Reversal |  |  | (17,557)
December 31 | 79,815 | 63,498 | 36,157
Provision for deficiency compensation [member] |  |  |
Disclosure of details of valuation and qualifying accounts [Line Items] |  |  |
January 1 | 1,998 | 29,352 | 57,155
Additions charged to expense or deduction of revenue | 4,358 | 5,204 | 14,211
Deduction/Write-offs/Reversal | (2,893) | (32,558) | (42,014)
December 31 | 3,463 | 1,998 | 29,352
Sales for allowance [member] |  |  |
Disclosure of details of valuation and qualifying accounts [Line Items] |  |  |
January 1 | 26,000 | 32,627 | 70,156
Additions charged to expense or deduction of revenue | 21,916 | 63,863 | 44,950
Deduction/Write-offs/Reversal | (38,052) | (70,490) | (82,479)
December 31 | $ 9,864 | $ 26,000 | $ 32,627

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- Definition Valuation allowances and reserves. + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- Definition Valuation allowances and reserves charged to expense. + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
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- Definition Valuation allowances and reserves deductions. + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Details
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- Details
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- Details
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- Details
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