XML 143 R139.htm IDEA: XBRL DOCUMENT
v3.20.1

Treasury Stock - Additional Information (Detail) shares in Thousands, $ in Thousands | 5 Months Ended
--- | ---
Aug. 06, 2019 TWD ($) shares
Statement [line items] |
Approval for number of treasury stock cancelled | shares | 25,570
Cancellation of treasury stock | $ | $ 962,503

X
- Definition The amount of treasury stock cancelled during the period. [Refer: Treasury shares] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 106 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_106_d&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_CancellationOfTreasuryShares
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Approval for number of treasury shares cancelled. + References No definition available. + Details
Name: | imos_ApprovalForNumberOfTreasurySharesCancelled
Namespace Prefix: | imos_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

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