| Goodwill and Other Intangible Assets - Rollforward of Goodwill (Details) - USD ($) $ in Millions | 12 Months Ended | |
|---|---|---|
| Mar. 31, 2022 | Mar. 31, 2021 | |
| Goodwill [Roll Forward] | ||
| Balance, beginning | $ 209.3 | |
| Balance, ending | 199.5 | $ 209.3 | 
| Europe Building Products | ||
| Goodwill [Roll Forward] | ||
| Balance, beginning | 209.3 | 196.9 | 
| Foreign exchange impact | (9.8) | 12.4 | 
| Balance, ending | $ 199.5 | $ 209.3 | 
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- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available. 
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- Details 
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