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Disposal of Subsidiaries - Summary of Gain on Disposal of Subsidiaries (Detail) $ in Thousands, $ in Thousands | 1 Months Ended | 12 Months Ended
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Jun. 30, 2017 TWD ($) | Jun. 30, 2017 USD ($) | Dec. 31, 2017 TWD ($) | Dec. 31, 2017 USD ($)
Disclosure of gain from disposals of subsidiaries [Line Items] |  |  |  |
Total consideration |  |  | $ (7,046,464) | $ (237,735)
KSDY [member] |  |  |  |
Disclosure of gain from disposals of subsidiaries [Line Items] |  |  |  |
Total consideration | $ 7,046,464 | $ 237,735 |  |
Net assets disposed of | (1,457,007) | (49,157) |  |
Gain on disposal of KSDY | $ 5,589,457 | $ 188,578 |  |

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- Definition The amount of assets, other than cash or cash equivalents, in subsidiaries or other businesses over which control is obtained or lost. [Refer: Subsidiaries [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 7 -IssueDate 2017-01-01 -Paragraph 40 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2017-03-01&anchor=para_40_d&doctype=Standard -URIDate 2017-03-09 + Details
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