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Significant Contingent Liabilities and Unrecognized Commitments - Additional Information (Detail)
$ in Thousands, $ in Thousands
 1 Months Ended 12 Months Ended
Dec. 31, 2013
Dec. 31, 2021
TWD ($)
Dec. 31, 2021
USD ($)
Dec. 31, 2020
TWD ($)
Dec. 31, 2019
TWD ($)
Dec. 31, 2021
USD ($)
Disclosure of contingent liabilities [line items]            
Unused letters of credit   $ 74,000   $ 2,000   $ 2,668
Committed to purchase property, plant and equipment   52,678,554   32,627,411   1,899,011
Prepayment of property, plant and equipment   3,761,120 $ 135,585 1,968,779    
Construction contract related to real estate business   59 2 602,548    
Letter of credits   738,628   671,721   26,627
Approved contribution in consideration of corporate social responsibility for environmental protection   100,000       3,605
Amount contributed related party transactions   110,000 3,965 100,000 $ 100,000  
ASE Environmental Protection And Sustainability Foundation [Member]            
Disclosure of contingent liabilities [line items]            
Amount contributed related party transactions   100,000 3,605 $ 100,000 $ 0  
ASE Cultural and Educational Foundation [Member]            
Disclosure of contingent liabilities [line items]            
Amount contributed related party transactions   20,000 $ 721      
Taiwan [member]            
Disclosure of contingent liabilities [line items]            
Contractual period for environmental protection 30 years          
Contribution to be made for environmental protection   $ 3,000,000       $ 108,147