Annual report pursuant to Section 13 and 15(d)

Long-Term Debt - Schedule of Long-Term Debt (Detail)

Long-Term Debt - Schedule of Long-Term Debt (Detail) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Feb. 28, 2014
Debt Instrument [Line Items]      
Borrowings under the senior secured credit facility $ 850.0us-gaap_LineOfCredit $ 931.3us-gaap_LineOfCredit  
Total 1,811.7us-gaap_LongTermDebt 931.3us-gaap_LongTermDebt  
Less: current portion 100.0us-gaap_LongTermDebtCurrent 81.3us-gaap_LongTermDebtCurrent  
Long-term portion 1,711.7us-gaap_LongTermDebtNoncurrent 850.0us-gaap_LongTermDebtNoncurrent  
Convertible Senior Notes [Member]      
Debt Instrument [Line Items]      
Convertible senior notes, carrying value of liability component 961.7us-gaap_ConvertibleDebt
/ us-gaap_LongtermDebtTypeAxis
= hlf_ConvertibleSeniorNotesMember
Total     $ 930.9us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= hlf_ConvertibleSeniorNotesMember