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Income Taxes - Additional Information (Detail) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Income Tax Contingency [Line Items]        
Effective tax rate     10.50%us-gaap_EffectiveIncomeTaxRateContinuingOperations  
Statutory income tax rate 35.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate      
Net deferred tax assets $ 577us-gaap_DeferredTaxAssetsLiabilitiesNet $ 2,244us-gaap_DeferredTaxAssetsLiabilitiesNet $ 4,374us-gaap_DeferredTaxAssetsLiabilitiesNet  
Deferred tax assets, valuation allowance amount 194,739us-gaap_DeferredTaxAssetsValuationAllowance 178,729us-gaap_DeferredTaxAssetsValuationAllowance 162,968us-gaap_DeferredTaxAssetsValuationAllowance 200,056us-gaap_DeferredTaxAssetsValuationAllowance
Net operating loss carry-forwards 315,344us-gaap_OperatingLossCarryforwards      
Net operating loss utilized 1,219mx_OperatingLossCarryforwardsUtilizedDuringPeriod 69,159mx_OperatingLossCarryforwardsUtilizedDuringPeriod 86,938mx_OperatingLossCarryforwardsUtilizedDuringPeriod  
Net operating loss expiration date 2024      
Unrecognized tax benefits 3,491mx_UnrecognizedTaxBenefitsRecordedLiability 3,706mx_UnrecognizedTaxBenefitsRecordedLiability 3,820mx_UnrecognizedTaxBenefitsRecordedLiability  
Income tax benefits by reversing liabilities 110mx_RecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations 106mx_RecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations 5mx_RecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations  
Income tax expenses for uncertain tax positions 44mx_IncomeTaxExpenseReservesOnUncertainTaxPositions 7mx_IncomeTaxExpenseReservesOnUncertainTaxPositions 55mx_IncomeTaxExpenseReservesOnUncertainTaxPositions  
Recognized interest and penalties as income tax expense 10us-gaap_IncomeTaxExaminationPenaltiesAndInterestExpense 20us-gaap_IncomeTaxExaminationPenaltiesAndInterestExpense 139us-gaap_IncomeTaxExaminationPenaltiesAndInterestExpense  
Total interest and penalties accrued 480us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued 530us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued 544us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued  
MagnaChip Semiconductor, Ltd. [Member]        
Income Tax Contingency [Line Items]        
Statutory income tax rate 24.20%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
/ dei_LegalEntityAxis
= mx_MagnachipSemiconductorLtdMember		 24.20%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
/ dei_LegalEntityAxis
= mx_MagnachipSemiconductorLtdMember		 24.20%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
/ dei_LegalEntityAxis
= mx_MagnachipSemiconductorLtdMember		  
Korean Statutory Tax Rate [Member]        
Income Tax Contingency [Line Items]        
Tax credit carry-forwards 9,561us-gaap_TaxCreditCarryforwardAmount
/ us-gaap_TaxCreditCarryforwardAxis
= mx_KoreanStatutoryTaxRateMember		      
Net operating loss carry-forwards, expiration period 2015 to 2019      
Dutch [Member]        
Income Tax Contingency [Line Items]        
Tax credit carry-forwards 15,210us-gaap_TaxCreditCarryforwardAmount
/ us-gaap_TaxCreditCarryforwardAxis
= mx_DutchStatutoryTaxRateMember		      
Net operating loss carry-forwards, expiration period Indefinite period of time      
U.S [Member]        
Income Tax Contingency [Line Items]        
Tax credit carry-forwards $ 390us-gaap_TaxCreditCarryforwardAmount
/ us-gaap_TaxCreditCarryforwardAxis
= mx_UsStatutoryTaxRateMember