| Cover Page | Jun. 17, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K/A |
| Document Period End Date | Jun. 17, 2020 |
| Entity Registrant Name | AMKOR TECHNOLOGY, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 000-29472 |
| Entity Tax Identification Number | 23-1722724 |
| Entity Address, Address Line One | 2045 EAST INNOVATION CIRCLE |
| Entity Address, City or Town | TEMPE |
| Entity Address, State or Province | AZ |
| Entity Address, Postal Zip Code | 85284 |
| City Area Code | 480 |
| Local Phone Number | 821-5000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.001 par value |
| Trading Symbol | AMKR |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001047127 |
| Amendment Flag | true |
