XML 46 R169.htm IDEA: XBRL DOCUMENT
v3.20.1

Financial Risk Management and Fair Values of Financial Instruments - Summary of Movements in Relation to Loss Allowance for Contract Assets, Accounts Receivable and Other Receivables (Detail) - TWD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018
Disclosure of detailed information about financial instruments [Line Items] |  |
Financial assets beginning balance | $ 9,932,223 |
Financial assets ending balance | 9,642,833 | $ 9,932,223
Contract assets [member] |  |
Disclosure of detailed information about financial instruments [Line Items] |  |
Financial assets beginning balance | (135) |
Provision for impairment loss | 0 | (20)
Reversal of impairment loss | 21 |
Financial assets ending balance | (114) | (135)
Contract assets [member] | IFRS 9 [member] |  |
Disclosure of detailed information about financial instruments [Line Items] |  |
Financial assets beginning balance |  | (115)
Adjustments for applying new standards |  | (115)
Accounts and notes receivable including related parties [member] |  |
Disclosure of detailed information about financial instruments [Line Items] |  |
Financial assets beginning balance | (2,141) |
Provision for impairment loss | 0 | (322)
Reversal of impairment loss | 790 |
Financial assets ending balance | (1,351) | (2,141)
Accounts and notes receivable including related parties [member] | IFRS 9 [member] |  |
Disclosure of detailed information about financial instruments [Line Items] |  |
Financial assets beginning balance |  | (1,819)
Adjustments for applying new standards |  | (1,819)
Other receivable including related parties [member] |  |
Disclosure of detailed information about financial instruments [Line Items] |  |
Financial assets beginning balance | (13) |
Provision for impairment loss | (5) | (7)
Reversal of impairment loss | 0 | 1
Financial assets ending balance | $ (18) | (13)
Other receivable including related parties [member] | IFRS 9 [member] |  |
Disclosure of detailed information about financial instruments [Line Items] |  |
Financial assets beginning balance |  | (7)
Adjustments for applying new standards |  | $ (7)

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_DisclosureOfFinancialInstrumentsLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of assets that are: (a) cash; (b) an equity instrument of another entity; (c) a contractual right: (i) to receive cash or another financial asset from another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially favourable to the entity; or (d) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to receive a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose the entity’s own equity instruments do not include puttable financial instruments classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. [Refer: Financial instruments, class [member]; Financial liabilities] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2019-01-01 -Paragraph 25 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_25&doctype=Standard -URIDate 2019-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2019-01-01 -Paragraph 35H -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_35H&doctype=Standard -URIDate 2019-03-27 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2019-01-01 -Paragraph 35I -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_35I&doctype=Standard -URIDate 2019-03-27 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2019-01-01 -Paragraph 35M -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_35M&doctype=Standard -URIDate 2019-03-27 Reference 5: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 7 -IssueDate 2019-01-01 -Paragraph 35N -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_35N&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_FinancialAssets
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount recognised as a reduction of the carrying amount of an asset or cash-generating unit to its recoverable amount. [Refer: Carrying amount [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 36 -IssueDate 2019-01-01 -Paragraph 130 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2019-en-r&anchor=para_130_b&doctype=Standard -URIDate 2019-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 36 -IssueDate 2019-01-01 -Paragraph 130 -Subparagraph d -Clause ii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2019-en-r&anchor=para_130_d_ii&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_ImpairmentLoss
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount recognised as an increase of the carrying amount of an asset or cash-generating unit to its recoverable amount when an impairment loss had been previously recognised. [Refer: Impairment loss] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 36 -IssueDate 2019-01-01 -Paragraph 130 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2019-en-r&anchor=para_130_b&doctype=Standard -URIDate 2019-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 36 -IssueDate 2019-01-01 -Paragraph 130 -Subparagraph d -Clause ii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=36&code=ifrs-tx-2019-en-r&anchor=para_130_d_ii&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_ReversalOfImpairmentLoss
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Increase decrease due to application of new accounting guidance. + References No definition available. + Details
Name: | imos_IncreaseDecreaseDueToApplicationOfNewAccountingGuidance
Namespace Prefix: | imos_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | ifrs-full_ClassesOfFinancialInstrumentsAxis=ifrs-full_ContractAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_EffectOfOverlayApproachReclassificationAxis=imos_IFRS9Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialInstrumentsAxis=imos_AccountsReceivableIncludingRelatedPartiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialInstrumentsAxis=imos_OtherReceivableIncludingRelatedPartiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |