Operating Segments Information - Summary of Revenue from Major Products and Services (Detail) $ in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2017 TWD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 TWD ($)	Dec. 31, 2015 TWD ($)
Disclosure of products and services [line items]
OPERATING REVENUES	$ 290,441,208	$ 9,798,961	$ 274,884,107	$ 283,302,536
Packaging service [member]
Disclosure of products and services [line items]
OPERATING REVENUES	126,225,119	4,258,607	125,282,829	116,607,314
Testing service [member]
Disclosure of products and services [line items]
OPERATING REVENUES	26,157,277	882,499	27,031,750	25,191,916
Electronic components manufacturing service [member]
Disclosure of products and services [line items]
OPERATING REVENUES	133,948,016	4,519,164	115,395,130	138,242,100
Other products and services [member]
Disclosure of products and services [line items]
OPERATING REVENUES	$ 4,110,796	$ 138,691	$ 7,174,398	$ 3,261,206

The income arising in the course of an entity's ordinary activities. Income is increases in economic benefits during the accounting period in the form of inflows or enhancements of assets or decreases of liabilities that result in an increase in equity, other than those relating to contributions from equity participants.

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+ Details