Contents of Significant Accounts - Details of Distribution of Employees' Compensation and Directors' Compensation (Detail) - TWD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Analysis Of Income And Expense [Abstract]
Employees’ compensation – Cash	$ 2,581,675	$ 1,132,952	$ 1,400,835
Directors’ compensation	$ 32,369	$ 10,259	$ 7,624

The amount of expense from employee benefits (other than termination benefits) that are expected to be settled wholly within twelve months after the end of the annual reporting period in which the employees render the related services.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 112
-Subparagraph c
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-URIDate 2020-01-01

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration