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Significant Commitments and Contingencies - Future Minimum Lease Obligation Payable under Operating Lease Contracts (Detail) $ in Thousands | Dec. 31, 2018 TWD ($)
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Disclosure of finance lease and operating lease by lessee [Line Items] |
Minimum finance lease payments payable | $ 320,214
Within 1 year [member] |
Disclosure of finance lease and operating lease by lessee [Line Items] |
Minimum finance lease payments payable | 68,631
1-5 years [member] |
Disclosure of finance lease and operating lease by lessee [Line Items] |
Minimum finance lease payments payable | 140,137
Over 5 years [member] |
Disclosure of finance lease and operating lease by lessee [Line Items] |
Minimum finance lease payments payable | $ 111,446

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- Definition Disclosure of lessee. + References No definition available. + Details
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Namespace Prefix: | imos_
Data Type: | xbrli:stringItemType
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Period Type: | duration

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- Definition The amount of future minimum lease payments payable under non-cancellable operating leases. + References No definition available. + Details
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Namespace Prefix: | imos_
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- Details
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- Details
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Namespace Prefix: |
Data Type: | na
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- Details
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Namespace Prefix: |
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Balance Type: |
Period Type: |