| Document and Entity Information | May 10, 2021 |
| Cover [Abstract] | |
| Entity Registrant Name | MAGNACHIP SEMICONDUCTOR Corp |
| Amendment Flag | false |
| Entity Central Index Key | 0001325702 |
| Document Type | 8-K |
| Document Period End Date | May 10, 2021 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-34791 |
| Entity Tax Identification Number | 83-0406195 |
| Entity Address, Address Line One | c/o MagnaChip Semiconductor S.A. |
| Entity Address, City or Town | Allée Scheffer |
| Entity Address, Postal Zip Code | L-2520 |
| Entity Address, Country | LU |
| City Area Code | 352 |
| Local Phone Number | 45-62-62 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, par value $0.01 per share |
| Trading Symbol | MX |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
