Operating Lease Arrangements - Summary of Future Minimum Lease Payments of Non-cancellable Operating Lease Agreements (Lessor) (Detail) - Dec. 31, 2018 $ in Thousands, $ in Thousands	USD ($)	TWD ($)
Disclosure of finance lease and operating lease by lessee [line items]
Minimum lease payments	$ 145,894	$ 4,465,827
Less than 1 year [member]
Disclosure of finance lease and operating lease by lessee [line items]
Minimum lease payments	29,954	916,891
1-5 years [member]
Disclosure of finance lease and operating lease by lessee [line items]
Minimum lease payments	78,139	2,391,843
More than 5 years [member]
Disclosure of finance lease and operating lease by lessee [line items]
Minimum lease payments	$ 37,801	$ 1,157,093

The amount of future minimum lease payments receivable under non-cancellable operating leases. Minimum lease payments are payments over the lease term that the lessee is or can be required to make, excluding contingent rent, costs for services and taxes to be paid by, and reimbursed to, the lessor, together with: (a) for a lessee, any amounts guaranteed by the lessee or by a party related to the lessee; or (b) for a lessor, any residual value guaranteed to the lessor by: (i) the lessee; (ii) a party related to the lessee; or (iii) a third party unrelated to the lessor that is financially capable of discharging the obligations under the guarantee.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2019-01-01
-Name IAS
-Number 17
-IssueDate 2018-01-01
-Paragraph 56
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=17&date=2018-03-02&anchor=para_56_a&doctype=Standard&book=b
-URIDate 2018-03-16

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant