XML 59 R64.htm IDEA: XBRL DOCUMENT v3.20.1

Leases - Additional Information (Details) $ in Millions	12 Months Ended
	Mar. 31, 2020 USD ($)
Lessee, Lease, Description [Line Items]
Impairment of right-of-use assets	$ 11.2
New Zealand Plant
Lessee, Lease, Description [Line Items]
Reduction in right of use asset	19.4
Operating lease liability	$ 19.4

X

- Definition

Operating Lease, Liability, Remeasurement

+ References

No definition available.

+ Details

Name:	jhx_OperatingLeaseLiabilityRemeasurement
Namespace Prefix:	jhx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Operating Lease, Right-of-Use Asset, Remeasurement

+ References

No definition available.

+ Details

Name:	jhx_OperatingLeaseRightofUseAssetRemeasurement
Namespace Prefix:	jhx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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

X

- Definition

Amount of loss from impairment of right-of-use asset from operating lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 25
-Paragraph 6
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=77888369&loc=SL77918431-209957

+ Details

Name:	us-gaap_OperatingLeaseImpairmentLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=jhx_NewZealandPlantMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: