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Investments Accounted for Using the Equity Method - Summary of Fair Values of Investments in Associates with Available Published Price Quotation (Detail) - Level 1 of fair value hierarchy [member] $ in Thousands, $ in Thousands	Dec. 31, 2018 USD ($)	Dec. 31, 2018 TWD ($)	Dec. 31, 2017 TWD ($)
Siliconware Precision Industries Co., Ltd. [member]
Disclosure of associates and joint ventures [line items]
Fair value of investments in associates with available published price quotation			$ 52,176,190
Hung Ching Development & Construction Co. [member]
Disclosure of associates and joint ventures [line items]
Fair value of investments in associates with available published price quotation	$ 50,222	$ 1,537,307	1,695,156
Advanced Microelectronic Products Inc. [member]
Disclosure of associates and joint ventures [line items]
Fair value of investments in associates with available published price quotation	12,085	369,925	$ 468,572
ChipMos Technologies Inc [member]
Disclosure of associates and joint ventures [line items]
Fair value of investments in associates with available published price quotation	$ 126,970	$ 3,886,561

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- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information about associate and joint ventures associated with domain members defined in one or many axes of the table.

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No definition available.

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- Definition

The fair value of investments in associates if there are quoted market prices for the investment. [Refer: Associates [member]; Investments in associates]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2018-01-01
-Paragraph 21
-Subparagraph b
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2018-03-01&anchor=para_21_b_iii&doctype=Standard
-URIDate 2018-03-16

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