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Income Tax - Summary of Unused Investment Credits (Detail) - 12 months ended Dec. 31, 2018 $ in Thousands, $ in Thousands	USD ($)	TWD ($)
Unused tax credits [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Remaining Creditable Amount	$ 20,619	$ 631,166
Purchase of machinery and equipment [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Expiry Year	2022
Purchase of machinery and equipment [member] | Unused tax credits [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Remaining Creditable Amount	$ 19,297	590,694
Others [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Expiry Year	2023 and thereafter
Others [member] | Unused tax credits [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Remaining Creditable Amount	$ 1,322	$ 40,472

X

- Definition

Unused tax credits expiration description.

+ References

No definition available.

+ 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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X

- Definition

The amount of deferred tax liabilities net of deferred tax assets, when the absolute amount of deferred tax liabilities is greater than the absolute amount of deferred tax assets. [Refer: Deferred tax assets; Deferred tax liabilities]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 12
-IssueDate 2018-01-01
-Paragraph 81
-Subparagraph g
-Clause i
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=12&date=2018-03-01&anchor=para_81_g_i&doctype=Standard
-URIDate 2018-03-16

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- Details

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- Details

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