XML 114 R95.htm IDEA: XBRL DOCUMENT
v3.19.1

Financial Assets at Fair Value Through Other Comprehensive Income - Summary of Investments in Debt Instruments at Fair Value Through Other Comprehensive Income (Detail) - Dec. 31, 2018 $ in Thousands, $ in Thousands | USD ($) | TWD ($)
--- | --- | ---
Financial assets at fair value through other comprehensive income [line items] |  |
Investments in debt instruments at FVTOCI | $ 33,222 | $ 1,016,924
Unsecured subordinate corporate bonds [member] |  |
Financial assets at fair value through other comprehensive income [line items] |  |
Investments in debt instruments at FVTOCI | $ 33,222 | $ 1,016,924

X
- Definition Fair value of investments in debt instruments designated as measured at fair value through other comprehensive income. + References No definition available. + Details
Name: | asx_FairValueOfInvestmentsInDebtInstrumentsDesignatedAsMeasuredAtFairValueThroughOtherComprehensiveIncome
Namespace Prefix: | asx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financial assets at fair value through other comprehensive income [line items] + References No definition available. + Details
Name: | asx_FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeLineItems
Namespace Prefix: | asx_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_CategoriesOfFinancialAssetsAxis=asx_UnsecuredSubordinateCorporateBondsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |