| Property, Plant and Equipment - Summary of Impairment Charges (Details) - USD ($) $ in Millions | 12 Months Ended | ||
|---|---|---|---|
| Mar. 31, 2022 | Mar. 31, 2021 | Mar. 31, 2020 | |
| Impaired Long-Lived Assets Held and Used [Line Items] | |||
| Impairment of property, plant & equipment | $ 0.4 | $ 2.0 | $ 64.5 | 
| North America Fiber Cement | |||
| Impaired Long-Lived Assets Held and Used [Line Items] | |||
| Impairment of property, plant & equipment | 0.4 | 2.0 | 44.0 | 
| Asia Pacific Fiber Cement | |||
| Impaired Long-Lived Assets Held and Used [Line Items] | |||
| Impairment of property, plant & equipment | 0.0 | 0.0 | 15.0 | 
| Europe Building Products | |||
| Impaired Long-Lived Assets Held and Used [Line Items] | |||
| Impairment of property, plant & equipment | $ 0.0 | $ 0.0 | $ 5.5 | 
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- 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. No definition available. 
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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://fasb.org/us-gaap/role/ref/legacyRef 
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