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Segment Information - Financial Segment Information for Operating Segments (Detail) $ in Thousands, $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2021 TWD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 TWD ($) | Dec. 31, 2019 TWD ($)
Revenue |  |  |  |
Revenue | $ 27,400,035 | $ 987,745 | $ 23,011,381 | $ 20,337,881
Operating profit (loss) | 5,562,389 | 200,519 | 3,566,502 | 2,457,119
Share of profit (loss) of associates | 625,733 | $ 22,557 | (147,329) | (154,926)
Interest expense | (120,998) |  | (162,400) | (171,075)
Purchase of property, plant and equipment | 6,552,702 |  | 4,133,615 | 4,896,656
Continuing operations [member] |  |  |  |
Revenue |  |  |  |
Revenue | 27,400,035 |  | 23,011,381 | 20,337,881
Operating profit (loss) | 5,562,389 |  | 3,566,502 | 2,457,119
Depreciation expenses | (4,634,112) |  | (4,175,519) | (3,731,914)
Share of profit (loss) of associates | 625,733 |  | (147,329) | (154,926)
Interest income | 9,980 |  | 27,778 | 64,368
Interest expense | (120,998) |  | (162,400) | (171,075)
Purchase of property, plant and equipment | 6,552,702 |  | 4,133,615 | 4,896,656
Continuing operations [member] | External [member] |  |  |  |
Revenue |  |  |  |
Revenue | 27,400,035 |  | 23,011,381 | 20,337,881
Continuing operations [member] | Operating segments [member] | Testing [member] |  |  |  |
Revenue |  |  |  |
Revenue | 5,899,600 |  | 5,002,730 | 4,257,800
Operating profit (loss) | 1,814,021 |  | 1,333,682 | 709,142
Depreciation expenses | (921,999) |  | (853,829) | (802,740)
Purchase of property, plant and equipment | 1,841,359 |  | 887,204 | 764,105
Continuing operations [member] | Operating segments [member] | Testing [member] | External [member] |  |  |  |
Revenue |  |  |  |
Revenue | 5,899,600 |  | 5,002,730 | 4,257,800
Continuing operations [member] | Operating segments [member] | Assembly [member] |  |  |  |
Revenue |  |  |  |
Revenue | 7,963,714 |  | 6,001,964 | 5,148,877
Operating profit (loss) | 857,304 |  | 67,730 | (227,096)
Depreciation expenses | (576,138) |  | (523,341) | (521,311)
Purchase of property, plant and equipment | 1,553,475 |  | 803,693 | 548,063
Continuing operations [member] | Operating segments [member] | Assembly [member] | External [member] |  |  |  |
Revenue |  |  |  |
Revenue | 7,963,714 |  | 6,001,964 | 5,148,877
Continuing operations [member] | Operating segments [member] | LCDD [member] |  |  |  |
Revenue |  |  |  |
Revenue | 8,211,099 |  | 7,023,003 | 6,922,205
Operating profit (loss) | 2,336,394 |  | 1,687,986 | 1,740,720
Depreciation expenses | (2,579,150) |  | (2,213,504) | (1,796,951)
Purchase of property, plant and equipment | 2,748,697 |  | 2,143,401 | 3,077,806
Continuing operations [member] | Operating segments [member] | LCDD [member] | External [member] |  |  |  |
Revenue |  |  |  |
Revenue | 8,211,099 |  | 7,023,003 | 6,922,205
Continuing operations [member] | Operating segments [member] | Bumping [member] |  |  |  |
Revenue |  |  |  |
Revenue | 5,325,622 |  | 4,983,684 | 4,008,999
Operating profit (loss) | 561,642 |  | 487,323 | 232,404
Depreciation expenses | (549,020) |  | (578,890) | (604,553)
Purchase of property, plant and equipment | 408,751 |  | 298,834 | 506,635
Continuing operations [member] | Operating segments [member] | Bumping [member] | External [member] |  |  |  |
Revenue |  |  |  |
Revenue | 5,325,622 |  | 4,983,684 | 4,008,999
Continuing operations [member] | Operating segments [member] | Others [member] |  |  |  |
Revenue |  |  |  |
Revenue | 43,808 |  | 39,646 | 32,808
Operating profit (loss) | (6,987) |  | (10,230) | 1,931
Depreciation expenses | (7,805) |  | (5,955) | (6,359)
Share of profit (loss) of associates | 1,211,177 |  | (320,578) | (370,351)
Interest income | 9,980 |  | 27,778 | 64,368
Interest expense | (120,998) |  | (162,400) | (171,075)
Purchase of property, plant and equipment | 420 |  | 483 | 47
Continuing operations [member] | Operating segments [member] | Others [member] | Intersegment [member] |  |  |  |
Revenue |  |  |  |
Revenue | 43,808 |  | 39,646 | 32,808
Continuing operations [member] | Elimination [member] |  |  |  |
Revenue |  |  |  |
Revenue | (43,808) |  | (39,646) | (32,808)
Operating profit (loss) | 15 |  | 11 | 18
Share of profit (loss) of associates | (585,444) |  | 173,249 | 215,425
Continuing operations [member] | Elimination [member] | Intersegment [member] |  |  |  |
Revenue |  |  |  |
Revenue | $ (43,808) |  | $ (39,646) | $ (32,808)

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