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Investments Accounted for Using the Equity Method - Summary of Investments in Associates Accounted for Using the Equity Method (Detail) $ in Thousands, $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2019 TWD ($) | Dec. 31, 2018 TWD ($) | Dec. 31, 2019 USD ($)
Disclosure of associates and joint ventures [line items] |  |  |
Investments in associates | $ 11,805,505 | $ 9,131,814 | $ 394,701
Deca Technologies Inc. [member] |  |  |
Disclosure of associates and joint ventures [line items] |  |  |
Main Business | Holding company and the group engaged in manufacturing, development and marketing of wafer level packaging and interconnect technology |  |
Operating Location | British Cayman Islands |  |
Percentages of ownership held by the Group | 22.02% | 22.04% |
Hung Ching Development & Construction Co. [member] |  |  |
Disclosure of associates and joint ventures [line items] |  |  |
Main Business | Engaged in the development, construction and leasing of real estate properties |  |
Operating Location | R.O.C. |  |
Percentages of ownership held by the Group | 26.22% | 26.22% |
Hung Ching Kwan Co. [member] |  |  |
Disclosure of associates and joint ventures [line items] |  |  |
Main Business | Engaged in the leasing of real estate properties |  |
Operating Location | R.O.C. |  |
Percentages of ownership held by the Group | 27.31% | 27.31% |
ChipMOS Technologies Inc. [member] |  |  |
Disclosure of associates and joint ventures [line items] |  |  |
Main Business | Engaged in the packaging and testing of semiconductors |  |
Operating Location | R.O.C. |  |
Percentages of ownership held by the Group | 20.48% | 20.47% |
Yann Yuan Investment Co., Ltd. [member] |  |  |
Disclosure of associates and joint ventures [line items] |  |  |
Main Business | Engaged in investing activities |  |
Operating Location | R.O.C. |  |
Percentages of ownership held by the Group | 32.21% | 32.21% |
M-Universe Investments Pte. Ltd. [member] |  |  |
Disclosure of associates and joint ventures [line items] |  |  |
Main Business | Investment company |  |
Operating Location | Singapore |  |
Percentages of ownership held by the Group | 42.23% |  |
Advanced Microelectronic Products Inc AMPI [Member] |  |  |
Disclosure of associates and joint ventures [line items] |  |  |
Main Business | Engaged in the manufacturing of integrated circuit |  |
Operating Location | R.O.C. |  |
Percentages of ownership held by the Group |  | 38.76% |
Cost [member] |  |  |
Disclosure of associates and joint ventures [line items] |  |  |
Investments in associates before deferred gain on transfer of land | $ 12,105,654 | $ 9,431,963 | 404,736
Cost [member] | Deca Technologies Inc. [member] |  |  |
Disclosure of associates and joint ventures [line items] |  |  |
Investments in associates before deferred gain on transfer of land | 323,423 | 866,312 | 10,813
Cost [member] | Hung Ching Development & Construction Co. [member] |  |  |
Disclosure of associates and joint ventures [line items] |  |  |
Investments in associates before deferred gain on transfer of land | 1,380,162 | 1,095,233 | 46,144
Cost [member] | Hung Ching Kwan Co. [member] |  |  |
Disclosure of associates and joint ventures [line items] |  |  |
Investments in associates before deferred gain on transfer of land | 283,105 | 295,772 | 9,465
Cost [member] | ChipMOS Technologies Inc. [member] |  |  |
Disclosure of associates and joint ventures [line items] |  |  |
Investments in associates before deferred gain on transfer of land | 4,370,075 | 4,237,982 | 146,108
Cost [member] | Yann Yuan Investment Co., Ltd. [member] |  |  |
Disclosure of associates and joint ventures [line items] |  |  |
Investments in associates before deferred gain on transfer of land | 3,934,190 | 2,752,530 | 131,534
Cost [member] | M-Universe Investments Pte. Ltd. [member] |  |  |
Disclosure of associates and joint ventures [line items] |  |  |
Investments in associates before deferred gain on transfer of land | 1,814,699 |  | 60,672
Cost [member] | Advanced Microelectronic Products Inc AMPI [Member] |  |  |
Disclosure of associates and joint ventures [line items] |  |  |
Investments in associates before deferred gain on transfer of land |  | 184,134 |
Deferred gain on transfer of land [member] |  |  |
Disclosure of associates and joint ventures [line items] |  |  |
Investments in associates | $ 300,149 | $ 300,149 | $ 10,035

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