XML 170 R147.htm IDEA: XBRL DOCUMENT
v3.21.1

Income Tax Expense - Additional Information (Detail) - TWD ($) $ in Thousands |  | 3 Months Ended |  |
--- | --- | --- | --- | ---
Oct. 31, 2016 | Jun. 30, 2020 | Dec. 31, 2020 | Dec. 31, 2019
Disclosure of income tax expense [Line Items] |  |  |  |
Taxable temporary differences not recognized as deferred tax liaibility |  |  | $ 45,005 | $ 180,395
Reduction of unappropriated retained earnings through capital transfer | $ 5,052,343 |  |  |
Income taxes paid (refund) |  | $ 138,941 |  |

X
- Definition The cash flows from income taxes paid or refunded. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 35 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_35&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_IncomeTaxesPaidRefund
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Decrease unappropriated retained earnings through transfer to capital. + References No definition available. + Details
Name: | imos_DecreaseUnappropriatedRetainedEarningsThroughTransferToCapital
Namespace Prefix: | imos_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Deductible temporary differences for which no deferred tax liability is recognized. + References No definition available. + Details
Name: | imos_DeductibleTemporaryDifferencesForWhichNoDeferredTaxLiabilityIsRecognised
Namespace Prefix: | imos_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Disclosure of income tax expense. + References No definition available. + Details
Name: | imos_DisclosureOfIncomeTaxExpenseLineItems
Namespace Prefix: | imos_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration