|
Income Taxes - Reconciliation of Unrecognized Tax Benefits and Interest and Penalties (Detail) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | ||
|---|---|---|---|
|
Mar. 31, 2015
|
Mar. 31, 2014
|
Mar. 31, 2013
|
|
| Income Tax Disclosure [Abstract] | |||
| Unrecognized tax benefits, Beginning balance | $ 0.5us-gaap_UnrecognizedTaxBenefits | $ 1.5us-gaap_UnrecognizedTaxBenefits | $ 2.6us-gaap_UnrecognizedTaxBenefits |
| Unrecognized tax benefits, Additions for tax positions of the current year | 4.2us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions | 0.1us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions | 0.1us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions |
| Unrecognized tax benefits, Additions for tax positions of prior year | 0.2us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions | 0.1us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions | 2.6us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions |
| Unrecognized tax benefits, Expiration of statute of limitations | (2.8)us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations | ||
| Unrecognized tax benefits, Settlements paid during the current period | (1.2)us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities | ||
| Unrecognized tax benefits, Other reductions for the tax positions of prior periods | (1.0)jhx_UnrecognizedTaxBenefitsOtherDecreasesResultingFromPriorPeriodTaxPositions | ||
| Unrecognized tax benefits, Ending Balance | 4.9us-gaap_UnrecognizedTaxBenefits | 0.5us-gaap_UnrecognizedTaxBenefits | 1.5us-gaap_UnrecognizedTaxBenefits |
| Interest and Penalties, Beginning balance | 0.1us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued | 0.9us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued | |
| Interest and Penalties, Additions for tax positions of the current year | 0.1jhx_InterestAndPenaltiesAdditionsForTaxPositionsOfCurrentYear | ||
| Interest and Penalties, Additions for tax positions of prior year | 0.2jhx_InterestAndPenaltiesAdditionsDeletionsForTaxPositionsOfPriorYear | (0.1)jhx_InterestAndPenaltiesAdditionsDeletionsForTaxPositionsOfPriorYear | |
| Interest and Penalties, Expiration of statute of limitations | (0.7)jhx_TaxExpensesOnInterestAndPenaltiesRelatedToLapsesInStatutesOfLimitationsAndAuditSettlements | ||
| Interest and Penalties, Settlements paid during the current period | 0jhx_InterestAndPenaltiesSettlementsPaidDuringCurrentPeriod | ||
| Interest and Penalties, Other reductions for the tax positions of prior periods | (0.1)jhx_InterestAndPenaltiesOtherDecreasesResultingFromPriorPeriodTaxPositions | ||
| Interest and Penalties, Ending Balance | $ 0.3us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued | $ 0.1us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued | |
| X | ||||||||||
|
- Definition
Interest and penalties additions deletions for tax positions of prior year. No definition available.
|
| X | ||||||||||
|
- Definition
Interest and penalties additions for tax positions of the current year. No definition available.
|
| X | ||||||||||
|
- Definition
Interest and penalties other decreases resulting from prior period tax positions. No definition available.
|
| X | ||||||||||
|
- Definition
Interest and penalties settlements paid during the current period. No definition available.
|
| X | ||||||||||
|
- Definition
Tax expenses on interest and penalties related to lapses in statutes of limitations and audit settlements. No definition available.
|
| X | ||||||||||
|
- Definition
Unrecognized tax benefits other decreases resulting from prior period tax positions. No definition available.
|
| X | ||||||||||
|
- Details
|
| X | ||||||||||
|
- Definition
Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|