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Summary of Significant Accounting Policies - Schedule of Exchange Rates Used to Convert Australian Dollar into US Dollars (Detail) | 12 Months Ended
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Mar. 31, 2015 ExchangeRate | Mar. 31, 2014 ExchangeRate | Mar. 31, 2013 ExchangeRate
Foreign Currency [Abstract] |  |  |
Assets and liabilities | 1.3096 jhx_AssetsAndLiabilitiesExchangeRate | 1.0845 jhx_AssetsAndLiabilitiesExchangeRate | 0.9597 jhx_AssetsAndLiabilitiesExchangeRate
Statements of operations | 1.1419 jhx_StatementsOfOperationsExchangeRate | 1.0716 jhx_StatementsOfOperationsExchangeRate | 0.9694 jhx_StatementsOfOperationsExchangeRate
Cash flows - beginning cash | 1.0845 jhx_CashFlowsBeginningCashExchangeRate | 0.9597 jhx_CashFlowsBeginningCashExchangeRate | 0.9614 jhx_CashFlowsBeginningCashExchangeRate
Cash flows - ending cash | 1.3096 jhx_CashFlowsEndingCashExchangeRate | 1.0845 jhx_CashFlowsEndingCashExchangeRate | 0.9597 jhx_CashFlowsEndingCashExchangeRate
Cash flows - current period movements | 1.1419 jhx_CashFlowsCurrentMovementsExchangeRate | 1.0716 jhx_CashFlowsCurrentMovementsExchangeRate | 0.9694 jhx_CashFlowsCurrentMovementsExchangeRate

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- Definition Assets And Liabilities Exchange Rate + References No definition available. + Details
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- Definition Cash Flows Beginning Cash Exchange Rate + References No definition available. + Details
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- Definition Cash Flows Current Movements Exchange Rate + References No definition available. + Details
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- Definition Cash Flows Ending Cash Exchange Rate + References No definition available. + Details
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- Definition Statements Of Operations Exchange Rate + References No definition available. + Details
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Balance Type: | na
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- Details
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