Disclosure of significant investments in associates and joint ventures.

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- Definition

Impairment loss on investments accounted for using equity method.

+ References

No definition available.

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- Definition

Investments in cash in associates.

+ References

No definition available.

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- Definition

The gain on the disposal of investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2016-01-13
-Paragraph 98
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2016-03-30&anchor=para_98_d&doctype=Standard
-URIDate 2016-03-31

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- Definition

The losses on the disposal of investments.

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- Definition

The proportion of ownership interest in an associate attributable to the entity. [Refer: Associates [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2016-01-13
-Paragraph 17
-Subparagraph b
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=27&date=2016-03-30&anchor=para_17_b_iii&doctype=Standard
-URIDate 2016-03-31

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2016-01-13
-Paragraph 16
-Subparagraph b
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=27&date=2016-03-30&anchor=para_16_b_iii&doctype=Standard
-URIDate 2016-03-31

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2016-01-13
-Paragraph 21
-Subparagraph a
-Clause iv
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2016-03-30&anchor=para_21_a_iv&doctype=Standard
-URIDate 2016-03-31

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Investments Accounted For Using Equity Method - Additional Information (Detail) $ in Millions, $ in Millions			1 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Apr. 30, 2015 TWD ($)	Dec. 31, 2017 TWD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 TWD ($)	Dec. 31, 2015 TWD ($)
Disclosure Of Significant Investments In Associates And Joint Ventures [Line Items]
Impairment loss on investments accounted for using equity method				$ 0.0	$ 0	$ 0.0	$ 8.0
Huada Digital Corporation ("HDD") [Member]
Disclosure Of Significant Investments In Associates And Joint Ventures [Line Items]
Disposal loss of investments						0.4
Chunghwa Benefit One Co., Ltd. ("CBO") [Member]
Disclosure Of Significant Investments In Associates And Joint Ventures [Line Items]
Disposal loss of investments				$ 0.2
KingwayTek Technology Co., Ltd. ("KWT") [Member]
Disclosure Of Significant Investments In Associates And Joint Ventures [Line Items]
Gain on disposal of investments							7.0
Dian Zuan Integrating Marketing Co., Ltd. ("DZIM") [Member]
Disclosure Of Significant Investments In Associates And Joint Ventures [Line Items]
Ownership interest in associates	22.00%	26.00%
Click Force Co., Ltd. ("CF") [Member]
Disclosure Of Significant Investments In Associates And Joint Ventures [Line Items]
Investments in cash in associates			$ 6.0
Ownership interest in associates				49.00%	49.00%
Alliance Digital Tech Co., Ltd. ("ADT") [Member]
Disclosure Of Significant Investments In Associates And Joint Ventures [Line Items]
Investments in cash in associates						$ 30.0
Ownership interest in associates						14.00%
Xiamen Sertec Business Technology Co., Ltd. [Member]
Disclosure Of Significant Investments In Associates And Joint Ventures [Line Items]
Gain on disposal of investments							1.0
MeWorks LIMITED (HK) ("MeWorks") [Member]
Disclosure Of Significant Investments In Associates And Joint Ventures [Line Items]
Impairment loss on investments accounted for using equity method							$ 8.0