Annual and transition report of foreign private issuers pursuant to Section 13 or 15(d)

Long-Term Debt - Schedule of Senior Notes Redemption Prices Expressed as Percentages of Principal Amount (Detail)

v2.4.1.9
Long-Term Debt - Schedule of Senior Notes Redemption Prices Expressed as Percentages of Principal Amount (Detail) (Senior Unsecured Notes Due 15 February 2023 [Member])
 12 Months Ended
Mar. 31, 2015
Debt Instrument, Redemption [Line Items]  
Redemption price, percentage 101.00%us-gaap_DebtInstrumentRedemptionPricePercentage
2018 [Member]
  
Debt Instrument, Redemption [Line Items]  
Redemption price, percentage 104.406%us-gaap_DebtInstrumentRedemptionPricePercentage
/ us-gaap_DebtInstrumentAxis
= jhx_SeniorUnsecuredNotesDueFifteenFebruaryTwoZeroTwoThreeMember
/ us-gaap_DebtInstrumentRedemptionPeriodAxis
= us-gaap_DebtInstrumentRedemptionPeriodOneMember
2019 [Member]
  
Debt Instrument, Redemption [Line Items]  
Redemption price, percentage 102.938%us-gaap_DebtInstrumentRedemptionPricePercentage
/ us-gaap_DebtInstrumentAxis
= jhx_SeniorUnsecuredNotesDueFifteenFebruaryTwoZeroTwoThreeMember
/ us-gaap_DebtInstrumentRedemptionPeriodAxis
= us-gaap_DebtInstrumentRedemptionPeriodTwoMember
2020 [Member]
  
Debt Instrument, Redemption [Line Items]  
Redemption price, percentage 101.469%us-gaap_DebtInstrumentRedemptionPricePercentage
/ us-gaap_DebtInstrumentAxis
= jhx_SeniorUnsecuredNotesDueFifteenFebruaryTwoZeroTwoThreeMember
/ us-gaap_DebtInstrumentRedemptionPeriodAxis
= us-gaap_DebtInstrumentRedemptionPeriodThreeMember
2021 and thereafter [Member]
  
Debt Instrument, Redemption [Line Items]  
Redemption price, percentage 100.00%us-gaap_DebtInstrumentRedemptionPricePercentage
/ us-gaap_DebtInstrumentAxis
= jhx_SeniorUnsecuredNotesDueFifteenFebruaryTwoZeroTwoThreeMember
/ us-gaap_DebtInstrumentRedemptionPeriodAxis
= jhx_DebtInstrumentRedemptionPeriodFourAndThereafterMember