Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2021	Feb. 14, 2022	Jun. 30, 2021
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Entity Registrant Name	Magnachip Semiconductor Corporation
Entity Central Index Key	0001325702
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 1,093,768,455
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Incorporation, State or Country Code	DE
Entity Common Stock, Shares Outstanding		45,810,893
Entity File Number	001-34791
Entity Tax Identification Number	83-0406195
Entity Address, Address Line One	c/o MagnaChip Semiconductor S.A. 1
Entity Address, City or Town	Allée Scheffer
Entity Address, Postal Zip Code	L-2520
City Area Code	352
Local Phone Number	45-62-62
Document Annual Report	true
Document Transition Report	false
Entity Address, Country	LU
ICFR Auditor Attestation Flag	true
Auditor Name	Samil PricewaterhouseCoopers
Auditor Firm ID	1103
Auditor Location	Seoul, Korea
Common Stock [Member]
Document Information [Line Items]
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	MX
Security Exchange Name	NYSE
Preferred Stock [Member]
Document Information [Line Items]
Title of 12(b) Security	Preferred Stock Purchase Rights
No Trading Symbol Flag	true
Security Exchange Name	NYSE