XML 86 R46.htm IDEA: XBRL DOCUMENT
v3.4.0.3

Summary of Significant Accounting Policies - Property, Plant and Equipment Estimated Useful Lives (Detail) | 12 Months Ended
--- | ---
Mar. 31, 2016
Buildings [Member] |
Property, Plant and Equipment [Line Items] |
Property, plant and equipment useful life | 40 years
Minimum [Member] | Building Improvements [Member] |
Property, Plant and Equipment [Line Items] |
Property, plant and equipment useful life | 5 years
Minimum [Member] | Manufacturing Machinery [Member] |
Property, Plant and Equipment [Line Items] |
Property, plant and equipment useful life | 5 years
Minimum [Member] | General Equipment [Member] |
Property, Plant and Equipment [Line Items] |
Property, plant and equipment useful life | 5 years
Minimum [Member] | Office Furniture and Equipment [Member] |
Property, Plant and Equipment [Line Items] |
Property, plant and equipment useful life | 3 years
Minimum [Member] | Computer Equipment, Software, and Software Development [Member] |
Property, Plant and Equipment [Line Items] |
Property, plant and equipment useful life | 3 years
Maximum [Member] | Building Improvements [Member] |
Property, Plant and Equipment [Line Items] |
Property, plant and equipment useful life | 10 years
Maximum [Member] | Manufacturing Machinery [Member] |
Property, Plant and Equipment [Line Items] |
Property, plant and equipment useful life | 20 years
Maximum [Member] | General Equipment [Member] |
Property, Plant and Equipment [Line Items] |
Property, plant and equipment useful life | 10 years
Maximum [Member] | Office Furniture and Equipment [Member] |
Property, Plant and Equipment [Line Items] |
Property, plant and equipment useful life | 10 years
Maximum [Member] | Computer Equipment, Software, and Software Development [Member] |
Property, Plant and Equipment [Line Items] |
Property, plant and equipment useful life | 7 years

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_PropertyPlantAndEquipmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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

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

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |