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Financial Statements Schedule: Valuation and Qualifying Accounts (Tables) | 12 Months Ended
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Dec. 31, 2019
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Disclosure Of Details Of Valuation And Qualifying Accounts |
|  | January 1 |  |  | Additions charged to expense |  |  | Deduction / Write-offs |  |  | December 31 |
|  | NT$000 |  |  | NT$000 |  |  | NT$000 |  |  | NT$000 |
Year of 2017 : |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Allowance for impairment of property, plant and equipment |  |  | 359,270 |  |  |  | 956 |  |  |  | (39,771 | ) |  |  | 320,455 |
Allowance for impairment of obsolescence and decline in market value of inventories |  |  | 154,841 |  |  |  | — |  |  |  | (101,127 | ) |  |  | 53,714 |
Year of 2018 : |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Allowance for impairment of property, plant and equipment |  |  | 320,455 |  |  |  | — |  |  |  | (2,862 | ) |  |  | 317,593 |
Allowance for impairment of obsolescence and decline in market value of inventories |  |  | 53,714 |  |  |  | — |  |  |  | (17,557 | ) |  |  | 36,157 |
Year of 2019 : |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Allowance for impairment of property, plant and equipment |  |  | 317,593 |  |  |  | 9,938 |  |  |  | (134,191 | ) |  |  | 193,340 |
Allowance for impairment of obsolescence and decline in market value of inventories |  |  | 36,157 |  |  |  | 27,341 |  |  |  | — |  |  |  | 63,498 |

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- Definition The entire disclosure for valuation and qualifying accounts and reserves. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 09 + Details
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