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Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | |||
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Mar. 31, 2013
Directors
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Mar. 31, 2012
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Mar. 31, 2011
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Mar. 31, 2006
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| Summary Of Significant Accounting Policies [Line Items] | ||||
| Asset impairments | $ 16.9 | $ 14.3 | ||
| Advertising expense | 8.9 | 8.6 | 7.9 | |
| Equity awards vested percentage after first year | 25.00% | |||
| Equity awards vested percentage after second year | 25.00% | |||
| Equity awards vested percentage after third year | 50.00% | |||
| Potential diluted common shares outstanding | 4.4 | 11.1 | 13.8 | |
| Asbestos provision net | $ 715.6 | |||
| Ownership percentage | 100.00% | 100.00% | 100.00% | |
| Number of directors appointed by Company | 3 | |||
| Directors appointed by NSW Government | 2 | |||
| Period of asbestos-related research and education contributions | 10 years | |||
| X | ||||||||||
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- Definition
Amount of asbestos provision net. No definition available.
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- Definition
Number of directors appointed to the AICF by the Company. No definition available.
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- Definition
Number of directors appointed to the AICF by the New South Wales Government. No definition available.
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- Definition
Percentage of ownership that the Company owns in James Hardie 117 Pty Ltd, which funds the AICF subject to the provisions of the Amended and Restated Final Funding Agreement. No definition available.
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- Definition
Total period of time the Company agreed to fund asbestos-related research and education initiatives. No definition available.
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| X | ||||||||||
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- Definition
Service equity awards percentage vested after the first year. No definition available.
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| X | ||||||||||
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- Definition
Service equity awards percentage vested after the second year. No definition available.
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| X | ||||||||||
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- Definition
Service equity awards percentage vested after the third year. No definition available.
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- Details
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| X | ||||||||||
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- Definition
Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- 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). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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