Business Combinations - Summary of Assets Acquired and Liabilities Assumed at the Date of Acquisition (Detail) - Dec. 31, 2019 $ in Thousands, $ in Thousands	TWD ($)	USD ($)
SPIL [member]
Disclosure of detailed information about business combination [Line Items]
Cash and cash equivalents	$ 20,088,970
Trade and other receivables	15,840,649
Inventories	5,693,644
Property, plant and equipment	81,985,622
Intangible assets	31,354,386
Others	24,945,922
Trade and other payables	(19,755,598)
Borrowings and bonds payables	(24,157,174)
Others	(3,963,201)
Fair value of identifiable net assets acquired	132,033,220
AMPI [member]
Disclosure of detailed information about business combination [Line Items]
Cash and cash equivalents	349,496	$ 11,685
Trade and other receivables	371,144	12,409
Inventories	403,887	13,503
Property, plant and equipment	683,207	22,842
Intangible assets	128,900	4,310
Others	237,766	7,949
Trade and other payables	(224,295)	(7,499)
Borrowings and bonds payables	(951,519)	(31,813)
Others	(148,723)	(4,972)
Fair value of identifiable net assets acquired	849,863	28,414
ASEEE [member]
Disclosure of detailed information about business combination [Line Items]
Cash and cash equivalents	23,197	776
Trade and other receivables	5,732	192
Inventories	11,033	369
Property, plant and equipment	1,361,572	45,522
Intangible assets	290,757	9,721
Others	317,888	10,628
Trade and other payables	(133,278)	(4,456)
Borrowings and bonds payables	(1,371,395)	(45,851)
Others	(290,273)	(9,705)
Fair value of identifiable net assets acquired	215,233	7,196
UGPL [Member]
Disclosure of detailed information about business combination [Line Items]
Cash and cash equivalents	108,718	3,635
Trade and other receivables	58,713	1,963
Inventories	229	8
Property, plant and equipment	525,048	17,554
Intangible assets	11,704	391
Others	99,112	3,314
Trade and other payables	(217,887)	(7,285)
Borrowings and bonds payables	(190,737)	(6,377)
Others	(63,708)	(2,130)
Fair value of identifiable net assets acquired	$ 331,192	$ 11,073

Other assets recognised as of acquisition date.

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- Definition

Other liabilities recognised as of acquisition date.

+ References

No definition available.

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- Definition

Trade and other receivables recognised as of acquisition date

+ References

No definition available.

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- Definition

The amount recognised as of the acquisition date for borrowings assumed in a business combination. [Refer: Borrowings; Business combinations [member]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition

The amount recognised as of the acquisition date for cash and cash equivalents acquired in a business combination. [Refer: Cash and cash equivalents; Business combinations [member]]

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Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

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No definition available.

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The amount recognised as of the acquisition date for net identifiable assets acquired or liabilities assumed in a business combination. [Refer: Business combinations [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
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The amount recognised as of the acquisition date for identifiable intangible assets acquired in a business combination. [Refer: Intangible assets other than goodwill; Business combinations [member]]

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- Definition

The amount recognised as of the acquisition date for inventory acquired in a business combination. [Refer: Inventories; Business combinations [member]]

+ References

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- Definition

The amount recognised as of the acquisition date for plant, property and equipment acquired in a business combination. [Refer: Property, plant and equipment; Business combinations [member]]

+ References

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- Definition

The amount recognised as of the acquisition date for trade and other payables assumed in a business combination. [Refer: Trade and other payables; Business combinations [member]]

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