XML 242 R223.htm IDEA: XBRL DOCUMENT v3.21.1
Operating Segments Information - Additional Information (Detail)
$ in Thousands, $ in Thousands
 12 Months Ended
Dec. 31, 2020
TWD ($)
Dec. 31, 2020
USD ($)
Dec. 31, 2019
TWD ($)
Dec. 31, 2018
TWD ($)
Disclosure of operating segments [line items]        
Operating revenue $ 476,978,710 $ 16,986,421 $ 413,182,184 $ 371,092,421
Packaging and EMS segments [member] | Customer One [member]        
Disclosure of operating segments [line items]        
Operating revenue $ 145,952,908 $ 5,197,753 103,987,781 $ 92,117,839
Packaging And Testing segments [member] | Customer Two [member]        
Disclosure of operating segments [line items]        
Operating revenue     $ 44,653,072