XML 168 R131.htm IDEA: XBRL DOCUMENT
v3.20.1

Long-term Prepayments for Lease - Additional Information (Detail) $ in Thousands, $ in Thousands | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | ---
Dec. 31, 2019 TWD ($) | Dec. 31, 2019 USD ($) | Jan. 01, 2019 TWD ($) | Jan. 01, 2019 USD ($) | Dec. 31, 2018 TWD ($) | Dec. 31, 2017 TWD ($)
Disclosure of finance lease and operating lease by lessee [line items] |  |  |  |  |  |
Long-term lease expire date | through 2048 to 2089 |  |  |  |  |
Investment properties | $ 12,854,071 | $ 429,758 |  |  | $ 7,738,379 | $ 8,119,436
Right-of-use assets | $ 9,792,221 | $ 327,390 |  |  |  |
IFRS16 [member] |  |  |  |  |  |
Disclosure of finance lease and operating lease by lessee [line items] |  |  |  |  |  |
Investment properties |  |  | $ 6,599,225 | $ 220,636 |  |
Right-of-use assets |  |  | $ 4,165,610 | $ 139,271 |  |
Bottom of range [member] |  |  |  |  |  |
Disclosure of finance lease and operating lease by lessee [line items] |  |  |  |  |  |
Long-term lease period | 30 years |  |  |  |  |
Top of range [member] |  |  |  |  |  |
Disclosure of finance lease and operating lease by lessee [line items] |  |  |  |  |  |
Long-term lease period | 70 years |  |  |  |  |

X
- Definition Disclosure of finance lease and operating lease. + References No definition available. + Details
Name: | asx_DisclosureOfFinanceLeaseAndOperatingLeaseLineItems
Namespace Prefix: | asx_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Long term lease expire date. + References No definition available. + Details
Name: | asx_LongTermLeaseExpireDate
Namespace Prefix: | asx_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Long term lease period. + References No definition available. + Details
Name: | asx_LongTermLeasePeriod
Namespace Prefix: | asx_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of property (land or a building - or part of a building - or both) held (by the owner or by the lessee as a right-of-use asset) to earn rentals or for capital appreciation or both, rather than for: (a) use in the production or supply of goods or services or for administrative purposes; or (b) sale in the ordinary course of business. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 40 -IssueDate 2019-01-01 -Paragraph 76 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=40&code=ifrs-tx-2019-en-r&anchor=para_76&doctype=Standard -URIDate 2019-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 40 -IssueDate 2019-01-01 -Paragraph 79 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=40&code=ifrs-tx-2019-en-r&anchor=para_79_d&doctype=Standard -URIDate 2019-03-27 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 54 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_54_b&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_InvestmentProperty
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount of assets that represent a lessee's right to use an underlying asset for the lease term. Underlying asset is an asset that is the subject of a lease, for which the right to use that asset has been provided by a lessor to a lessee. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 16 -IssueDate 2019-01-01 -Paragraph 53 -Subparagraph j -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2019-en-r&anchor=para_53_j&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_RightofuseAssets
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | ifrs-full_NewIFRSsAxis=asx_IFRS16Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_RangeAxis=ifrs-full_TopOfRangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |