Hedging Financial Instruments - Summary of hedging financial instruments (Detail) - Fair value hedges [member] - Interest rate futures contracts [member] - TWD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Financial assets- current
Financial assets current	$ 0.3	$ 0.1
Financial liabilities- current
Financial liabilities current	$ 10.2	$ 1.2

The amount of current financial liabilities. [Refer: Financial liabilities]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2020-01-01
-Paragraph 25
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_25&doctype=Standard
-URIDate 2020-01-01

Name:	ifrs-full_CurrentFinancialLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant