Operating Segments Information - Summary of Revenue from Major Products and Services (Detail) $ in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2018 USD ($)	Dec. 31, 2018 TWD ($)	Dec. 31, 2017 TWD ($)	Dec. 31, 2016 TWD ($)
Disclosure of products and services [line items]
Operating revenue	$ 12,123,242	$ 371,092,421	$ 290,441,208	$ 274,884,107
Packaging service [member]
Disclosure of products and services [line items]
Operating revenue	5,825,163	178,308,222	126,225,119	125,282,829
Testing service [member]
Disclosure of products and services [line items]
Operating revenue	1,172,924	35,903,202	26,157,277	27,031,750
Electronic components manufacturing service [member]
Disclosure of products and services [line items]
Operating revenue	4,962,116	151,890,384	133,948,016	115,395,130
Other products and services [member]
Disclosure of products and services [line items]
Operating revenue	$ 163,039	$ 4,990,613	$ 4,110,796	$ 7,174,398

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