XML 232 R213.htm IDEA: XBRL DOCUMENT
v3.19.1

Related Party Transactions - Additional Information (Detail) shares in Thousands, $ in Thousands, $ in Thousands | 1 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Feb. 28, 2018 USD ($) shares | Feb. 28, 2018 TWD ($) shares | Feb. 29, 2016 TWD ($) shares | Dec. 31, 2018 USD ($) | Dec. 31, 2018 TWD ($) | Dec. 31, 2017 USD ($) | Dec. 31, 2017 TWD ($) | Dec. 31, 2016 USD ($) | Dec. 31, 2016 TWD ($) | Dec. 31, 2018 TWD ($)
Patents and Technology License [member] |  |  |  |  |  |  |  |  |  |
Disclosure of transactions between related parties [line items] |  |  |  |  |  |  |  |  |  |
Amounts payable |  |  |  | $ 1,881 |  |  | $ 93,000 |  |  | $ 57,590
Deca Technologies Inc. [member] | Patents and Technology License [member] |  |  |  |  |  |  |  |  |  |
Disclosure of transactions between related parties [line items] |  |  |  |  |  |  |  |  |  |
Intangible assets acquired |  |  |  |  |  |  |  |  | $ 403,543 |
ASE Cultural and Educational Foundation [member] | Environmental charity [member] |  |  |  |  |  |  |  |  |  |
Disclosure of transactions between related parties [line items] |  |  |  |  |  |  |  |  |  |
Amount contributed related party transactions |  |  |  | $ 3,267 | $ 100,000 | $ 3,267 | $ 100,000 | $ 3,267 | 100,000 |
Associates [member] |  |  |  |  |  |  |  |  |  |
Disclosure of transactions between related parties [line items] |  |  |  |  |  |  |  |  |  |
Total consideration settled |  |  |  |  |  |  |  |  | 875,000 |
Associates [member] | Employee dormitory [member] |  |  |  |  |  |  |  |  |  |
Disclosure of transactions between related parties [line items] |  |  |  |  |  |  |  |  |  |
Amounts payable |  |  |  |  |  |  |  |  | $ 228,500 |
USI Enterprise Limited [member] |  |  |  |  |  |  |  |  |  |
Disclosure of transactions between related parties [line items] |  |  |  |  |  |  |  |  |  |
Repurchase of outstanding ordinary shares | shares | 1,283 | 1,283 | 1,801 |  |  |  |  |  |  |
Value of ordinary shares purchased | $ 21,341 | $ 653,244 | $ 1,130,650 |  |  |  |  |  |  |

X
- Definition Amount contributed related party transactions. + References No definition available. + Details
Name: | asx_AmountContributedRelatedPartyTransactions
Namespace Prefix: | asx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Repurchase of outstanding ordinary shares. + References No definition available. + Details
Name: | asx_RepurchaseOfOutstandingOrdinaryShares
Namespace Prefix: | asx_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Value of ordinary shares repurchased. + References No definition available. + Details
Name: | asx_ValueOfOrdinarySharesRepurchased
Namespace Prefix: | asx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amounts payable resulting from related party transactions. [Refer: Related parties [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 24 -IssueDate 2018-01-01 -Paragraph 20 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=24&date=2018-03-01&anchor=para_20&doctype=Standard -URIDate 2018-03-16 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 24 -IssueDate 2018-01-01 -Paragraph 18 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=24&date=2018-03-01&anchor=para_18_b&doctype=Standard -URIDate 2018-03-16 + Details
Name: | ifrs-full_AmountsPayableRelatedPartyTransactions
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table. + References No definition available. + Details
Name: | ifrs-full_DisclosureOfTransactionsBetweenRelatedPartiesLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount recognised as of the acquisition date for identifiable intangible assets acquired in a business combination. [Refer: Intangible assets other than goodwill; Business combinations [member]] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 3 -IssueDate 2018-01-01 -Paragraph B64 -Subparagraph i -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=3&date=2018-03-01&anchor=para_B64_i&doctype=Appendix&seq=2 -URIDate 2018-03-16 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 3 -IssueDate 2018-01-01 -Paragraph IE72 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=3&date=2018-03-01&anchor=para_IE72&doctype=Illustrative%20Examples -URIDate 2018-03-16 + Details
Name: | ifrs-full_IdentifiableIntangibleAssetsRecognisedAsOfAcquisitionDate
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount of liabilities settled by the entity on behalf of a related party in related party transactions. [Refer: Related parties [member]] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 24 -IssueDate 2018-01-01 -Paragraph 21 -Subparagraph j -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=24&date=2018-03-01&anchor=para_21_j&doctype=Standard -URIDate 2018-03-16 + Details
Name: | ifrs-full_SettlementOfLiabilitiesByEntityOnBehalfOfRelatedPartyRelatedPartyTransactions
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillAxis=asx_PatentsAndTechnologyLicenseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInAssociatesAxis=asx_DecaTechnologiesIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_CategoriesOfRelatedPartiesAxis=asx_ASECulturalAndEducationalFoundationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_TypesOfContractsAxis=asx_EnvironmentalCharityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_CategoriesOfRelatedPartiesAxis=ifrs-full_AssociatesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis=asx_EmployeeDormitoryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ConsolidatedStructuredEntitiesAxis=asx_USIEnterpriseLimitedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |