Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Derivative Assets and Liabilities Measured at Fair Value (Detail)

v2.4.1.9
Fair Value Measurements - Derivative Assets and Liabilities Measured at Fair Value (Detail) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value derivative assets $ 14.5us-gaap_DerivativeFairValueOfDerivativeAsset $ 8.0us-gaap_DerivativeFairValueOfDerivativeAsset
Fair value derivative liabilities 5.4us-gaap_DerivativeFairValueOfDerivativeLiability 5.1us-gaap_DerivativeFairValueOfDerivativeLiability
Foreign exchange currency contracts [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value derivative assets 14.5us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_ForeignExchangeContractMember
8.0us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_ForeignExchangeContractMember
Fair value derivative liabilities 5.4us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_ForeignExchangeContractMember
5.1us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_ForeignExchangeContractMember
Significant Other Observable Inputs (Level 2) [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value measurements, assets total 14.5us-gaap_AssetsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
8.0us-gaap_AssetsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
Fair value measurements, liabilities total 5.4us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
5.1us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
Significant Other Observable Inputs (Level 2) [Member] | Derivatives designated as hedging instruments [Member] | Foreign exchange currency contracts relating to inventory and intercompany management fee hedges [Member] | Prepaid expenses and other current assets [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value derivative assets 12.3us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember
/ us-gaap_DerivativeInstrumentRiskAxis
= hlf_ForeignExchangeCurrencyContractsRelatingToInventoryHedgesAndIntercompanyManagementFeeHedgesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember
5.7us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember
/ us-gaap_DerivativeInstrumentRiskAxis
= hlf_ForeignExchangeCurrencyContractsRelatingToInventoryHedgesAndIntercompanyManagementFeeHedgesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember
Significant Other Observable Inputs (Level 2) [Member] | Derivatives designated as hedging instruments [Member] | Foreign exchange currency contracts relating to inventory and intercompany management fee hedges [Member] | Accrued expenses [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value derivative liabilities 1.6us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_AccountsPayableAndAccruedLiabilitiesMember
/ us-gaap_DerivativeInstrumentRiskAxis
= hlf_ForeignExchangeCurrencyContractsRelatingToInventoryHedgesAndIntercompanyManagementFeeHedgesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember
4.4us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_AccountsPayableAndAccruedLiabilitiesMember
/ us-gaap_DerivativeInstrumentRiskAxis
= hlf_ForeignExchangeCurrencyContractsRelatingToInventoryHedgesAndIntercompanyManagementFeeHedgesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember
Significant Other Observable Inputs (Level 2) [Member] | Derivatives not designated as hedging instruments [Member] | Foreign exchange currency contracts [Member] | Prepaid expenses and other current assets [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value derivative assets 2.2us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_ForeignExchangeContractMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
2.3us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_ForeignExchangeContractMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
Significant Other Observable Inputs (Level 2) [Member] | Derivatives not designated as hedging instruments [Member] | Foreign exchange currency contracts [Member] | Accrued expenses [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value derivative liabilities $ 3.8us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_AccountsPayableAndAccruedLiabilitiesMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_ForeignExchangeContractMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
$ 0.7us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_AccountsPayableAndAccruedLiabilitiesMember
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_ForeignExchangeContractMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember