XML 49 R95.htm IDEA: XBRL DOCUMENT
v3.20.1

Operating Segment Information and Concentrations of Risk - Summary of Geographical Information 2 (Detail) $ in Millions, $ in Millions | 1 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2017 USD ($) | Dec. 31, 2017 AUD ($) | Mar. 31, 2020 USD ($) | Mar. 31, 2019 USD ($) | Mar. 31, 2018 USD ($)
Segment Reporting Information [Line Items] |  |  |  |  |
Research and development costs |  |  | $ 32.8 | $ 37.9 | $ 33.3
Selling, general and administrative expenses |  |  | 415.8 | 403.6 | 311.3
Asbestos adjustments | $ (43.6) | $ (56.8) | (58.2) | (22.0) | (156.4)
AICF SG&A expenses |  |  | 1.7 | (1.5) | (1.9)
Net interest (income) expense |  |  | (54.4) | (50.1) | (29.5)
Impairment of Property, Plant & Equipment |  |  | 64.5 | 9.1 | 0.7
Right-of-use assets |  |  | 11.2 |  |
Intangible assets |  |  | 1.4 |  |
Inventories |  |  | 2.9 |  |
Goodwill |  |  | 0.2 | 4.6 |
Asset Retirement Obligations |  |  | 5.8 |  |
Other |  |  | 1.2 |  |
Asset impairments |  |  | 84.4 | 15.9 | 0.0
Cost of Sales |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Other |  |  | 2.8 | 0.4 | 0.7
Property, Plant and Equipment |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Impairment of Property, Plant & Equipment |  |  | 61.7 |  |
Disposed of by Sale | Fontana Building | Buildings |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Gain from disposition |  |  | 0.0 | 0.0 | 3.4
General Corporate |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Asbestos adjustments |  |  | 58.2 | (22.0) | (156.4)
Assets held for sale |  |  | 0.4 |  |
Value of Asbestos-related assets |  |  | 443.9 | 486.8 |
Right-of-use assets |  |  | 0.0 |  |
Intangible assets |  |  | 1.4 |  |
Inventories |  |  | 0.0 |  |
Goodwill |  |  | 0.0 |  |
Asset Retirement Obligations |  |  | 0.0 |  |
Other |  |  | 0.0 |  |
Asset impairments |  |  | 1.4 |  |
General Corporate | Property, Plant and Equipment |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Impairment of Property, Plant & Equipment |  |  | 0.0 |  |
North America Fiber Cement |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Research and development costs |  |  | 5.3 | 6.5 | 6.1
Impairment of Property, Plant & Equipment |  |  | 44.0 | 3.0 | 0.7
Right-of-use assets |  |  | 0.0 |  |
Intangible assets |  |  | 0.0 |  |
Inventories |  |  | 0.0 |  |
Goodwill |  |  | 0.0 |  |
Asset Retirement Obligations |  |  | 0.0 |  |
Other |  |  | 0.0 |  |
Asset impairments |  |  | 41.2 | 2.6 |
North America Fiber Cement | Cost of Sales |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Other |  |  | 2.8 |  |
North America Fiber Cement | Property, Plant and Equipment |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Impairment of Property, Plant & Equipment |  |  | 41.2 |  |
Asia Pacific Fiber Cement |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Research and development costs |  |  | 1.8 | 2.1 | 1.8
Impairment of Property, Plant & Equipment |  |  | 15.0 | 0.0 | 0.0
Right-of-use assets |  |  | 11.2 |  |
Intangible assets |  |  | 0.0 |  |
Inventories |  |  | 2.9 |  |
Goodwill |  |  | 0.2 |  |
Asset Retirement Obligations |  |  | 5.8 |  |
Other |  |  | 1.2 |  |
Asset impairments |  |  | 36.3 |  |
Asia Pacific Fiber Cement | Other liabilities - non-current |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Asset Retirement Obligation |  |  | 8.0 |  |
Asia Pacific Fiber Cement | Property, Plant and Equipment |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Impairment of Property, Plant & Equipment |  |  | 15.0 |  |
Europe Building Products |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Research and development costs |  |  | 1.7 | 2.6 | 0.0
Impairment of Property, Plant & Equipment |  |  | 5.5 | 0.0 | 0.0
Right-of-use assets |  |  | 0.0 |  |
Intangible assets |  |  | 0.0 |  |
Inventories |  |  | 0.0 |  |
Goodwill |  |  | 0.0 | 0.0 |
Asset Retirement Obligations |  |  | 0.0 |  |
Other |  |  | 0.0 |  |
Asset impairments |  |  | 5.5 |  |
Europe Building Products | Property, Plant and Equipment |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Impairment of Property, Plant & Equipment |  |  | 5.5 |  |
Research and Development |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Research and development costs |  |  | 24.0 | 26.7 | 25.4
Selling, general and administrative expenses |  |  | 3.0 | 2.3 | 2.4
AICF Funding |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Net interest (income) expense |  |  | 1.4 | 2.0 | 1.9
Asia Pacific |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
New Zealand weathertightness claims (expense)/ benefit |  |  | 1.9 | 3.3 | 0.0
Goodwill |  |  | 0.2 | 0.0 |
Other Businesses |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Impairment of Property, Plant & Equipment |  |  | 0.0 | 6.1 | 0.0
Goodwill |  |  | 0.0 | 4.6 |
Asset impairments |  |  |  | 6.1 |
Other Businesses | Operating Segments |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Assets held for sale |  |  | 5.8 |  |
Assets disposed of |  |  | 5.4 |  |
Fermacell |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Acquisition costs |  |  | 0.0 | 0.0 | $ 10.0
Transaction and integration related costs |  |  | $ 13.7 | 21.8 |
Inventory fair value adjustment |  |  |  | 7.3 |
Goodwill | North America Fiber Cement |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Asset impairments |  |  |  | 0.0 |
Goodwill | Other Businesses |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Asset impairments |  |  |  | 4.6 |
Property, Plant and Equipment | North America Fiber Cement |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Asset impairments |  |  |  | 2.6 |
Property, Plant and Equipment | Other Businesses |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Asset impairments |  |  |  | 6.1 |
Finite-Lived Intangible Assets | North America Fiber Cement |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Asset impairments |  |  |  | 0.4 |
Finite-Lived Intangible Assets | Other Businesses |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Asset impairments |  |  |  | $ 2.2 |

X
- Definition AICF operating cost paid non claim handling. + References No definition available. + Details
Name: | jhx_AicfOperatingCostPaidNonClaimHandling
Namespace Prefix: | jhx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Comprised of changes in actuarial estimates received as of March 31 each year and the effect of foreign exchange movements in the asbestos related assets and liabilities which are denominated in Australian dollars. + References No definition available. + Details
Name: | jhx_AsbestosAdjustments
Namespace Prefix: | jhx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Asbestos related assets value. + References No definition available. + Details
Name: | jhx_AsbestosRelatedAssetsValue
Namespace Prefix: | jhx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Asset Retirement Obligation, Impairment + References No definition available. + Details
Name: | jhx_AssetRetirementObligationImpairment
Namespace Prefix: | jhx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Operating Lease, Right-of-Use, Impairment + References No definition available. + Details
Name: | jhx_OperatingLeaseRightofUseImpairment
Namespace Prefix: | jhx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Product liability accrual period expense benefit. + References No definition available. + Details
Name: | jhx_ProductLiabilityAccrualPeriodExpenseBenefit
Namespace Prefix: | jhx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=109226348&loc=d3e2420-110228 + Details
Name: | us-gaap_AssetImpairmentCharges
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
Name: | us-gaap_AssetRetirementObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of assets held-for-sale that are not part of a disposal group. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 15 -Paragraph 4 -Subparagraph (b)(2) -URI http://asc.fasb.org/extlink&oid=77912953&loc=d3e400-110220 + Details
Name: | us-gaap_AssetsHeldForSaleNotPartOfDisposalGroup
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount classified as assets attributable to disposal group held for sale or disposed of. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=109222160&loc=d3e1107-107759 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2941-110230 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 5B -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=109222650&loc=SL51721673-107760 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=109222160&loc=SL51721533-107759 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 5C -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=109222650&loc=SL51721675-107760 + Details
Name: | us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of direct costs of the business combination including legal, accounting, and other costs incurred to consummate the business acquisition. + References No definition available. + Details
Name: | us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Costs incurred to effect a business combination which have been expensed during the period. Such costs could include business integration costs, systems integration and conversion costs, and severance and other employee-related costs. + References No definition available. + Details
Name: | us-gaap_BusinessCombinationIntegrationRelatedCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition This element represents the amount of any measurement period adjustment (as defined) realized during the reporting period to inventory acquired in connection with a business combination for which the initial accounting was incomplete. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 4A -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84161108&loc=SL65897772-128472 + Details
Name: | us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentInventory
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of gain (loss) on sale or disposal of property, plant and equipment assets, including oil and gas property and timber property. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 + Details
Name: | us-gaap_GainLossOnSaleOfPropertyPlantEquipment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13854-109267 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13777-109266 + Details
Name: | us-gaap_GoodwillImpairmentLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of impairment loss resulting from write-down of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit to fair value. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16373-109275 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 + Details
Name: | us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2921-110230 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 958 -SubTopic 220 -Section 45 -Paragraph 11 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=114873921&loc=SL114875236-224282 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=109226348&loc=d3e2420-110228 + Details
Name: | us-gaap_ImpairmentOfLongLivedAssetsHeldForUse
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The net amount of operating interest income (expense). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.10) -URI http://asc.fasb.org/extlink&oid=114873765&loc=SL114874048-224260 + Details
Name: | us-gaap_InterestIncomeExpenseNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of loss from reductions in inventory due to subsequent measurement adjustments, including, but not limited to, physical deterioration, obsolescence, or changes in price levels. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 330 -SubTopic 10 -Section 35 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=68049868&loc=SL66093879-108312 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2) -URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 330 -SubTopic 10 -Section 35 -Paragraph 1C -URI http://asc.fasb.org/extlink&oid=68049868&loc=SL66093883-108312 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 330 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=66092785&loc=d3e4542-108314 + Details
Name: | us-gaap_InventoryWriteDown
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The charge against earnings resulting from the write down of long lived assets other than goodwill due to the difference between the carrying value and lower fair value. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2921-110230 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 + Details
Name: | us-gaap_OtherAssetImpairmentCharges
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 985 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6501960&loc=d3e128462-111756 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 730 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6420194&loc=d3e21568-108373 + Details
Name: | us-gaap_ResearchAndDevelopmentExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_SegmentReportingInformationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 330 -SubTopic 10 -Section 30 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=68048583&loc=d3e3636-108311 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.4) -URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227 + Details
Name: | us-gaap_SellingGeneralAndAdministrativeExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=us-gaap_CostOfSalesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ImpairedLongLivedAssetsHeldAndUsedByTypeAxis=us-gaap_PropertyPlantAndEquipmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DisposalGroupClassificationAxis=us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=jhx_FontanaBuildingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ConsolidationItemsAxis=us-gaap_CorporateNonSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=jhx_NorthAmericaFiberCementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=jhx_AsiaPacificFiberCementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_OtherNoncurrentLiabilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=jhx_EuropeBuildingProductsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=jhx_ResearchAndDevelopmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=jhx_AsbestosInjuriesCompensationFundMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=srt_AsiaPacificMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=jhx_OtherBusinessesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ConsolidationItemsAxis=us-gaap_OperatingSegmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=jhx_FermacellMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_GoodwillMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_PropertyPlantAndEquipmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_FiniteLivedIntangibleAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |