Interim Financial Statements (Policies)	3 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation. The Consolidated Financial Statements and related disclosures as of March 31, 2022, and for the three months ended March 31, 2022 and 2021, contained in this Form 10-Q (the “Consolidated Financial Statements”) are unaudited, pursuant to the rules and regulations of the SEC. The December 31, 2021 Consolidated Balance Sheet data contained in this Form 10-Q was derived from audited financial statements but does not include all disclosures required by accounting principles generally accepted in the United States of America (“U.S. GAAP”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to SEC rules and regulations. In our opinion, the Consolidated Financial Statements include all adjustments (consisting only of normal recurring adjustments) necessary for the fair statement of the results for the interim periods and should be read in conjunction with the financial statements included in the 2021 Form 10-K. The results of operations for the three months ended March 31, 2022 are not necessarily indicative of the results to be expected for the full year ending December 31, 2022. Unless the context otherwise requires, all references to “Amkor,” “we,” “us” or “our” are to Amkor Technology, Inc. and its wholly and majority-owned subsidiaries.
Use of Estimates	Use of Estimates. The Consolidated Financial Statements have been prepared in conformity with U.S. GAAP, using management’s best estimates and judgments where appropriate. These estimates and judgments affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements. The estimates and judgments will also affect the reported amounts for certain revenues and expenses during the reporting period. Actual results could differ materially from these estimates and judgments, as a result of, for example, the impact of the Covid-19 pandemic and any worsening of the global business and economic environment.
Goodwill	Goodwill. The balance of goodwill in the Consolidated Balance Sheets contained in this Form 10-Q reflects adjustments for foreign currency translation.
Income Taxes	We monitor on an ongoing basis our ability to utilize our deferred tax assets and whether there is a need for a related valuation allowance. In evaluating our ability to recover our deferred tax assets in the jurisdictions from which they arise, we consider all available positive and negative evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, tax-planning strategies and results of recent operations. We maintain a valuation allowance on certain U.S. and foreign deferred tax assets. Such valuation allowances are released as the related tax benefits are realized or when sufficient evidence exists to conclude that it is more likely than not that the deferred tax assets will be realized.
Commitments and Contingencies	In accordance with the accounting guidance for loss contingencies, including legal proceedings, lawsuits, pending claims and other legal matters, we accrue for a loss contingency when we conclude that the likelihood of a loss is probable and the amount of the loss can be reasonably estimated. We adjust our accruals from time to time as we receive additional information, but the loss we incur may be significantly greater than or less than the amount we have accrued. We disclose loss contingencies if we believe they are material and there is at least a reasonable possibility that a loss has been incurred. Attorney fees related to legal matters are expensed as incurred.