Goodwill and Other Intangible Assets - Rollforward of Goodwill and Indefinite Lived Assets (Details) - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2019 |
Mar. 31, 2018 |
Mar. 31, 2017 |
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| Goodwill [Roll Forward] | |||
| Balance - 31 March 2018 | $ 4,900,000 | ||
| Acquired during the period | 220,000,000 | ||
| Impairment | (4,600,000) | ||
| Foreign exchange impact | (19,200,000) | ||
| Balance - 31 March 2019 | 201,100,000 | $ 4,900,000 | |
| Indefinite-lived Intangible Assets [Roll Forward] | |||
| Balance - 31 March 2018 | 0 | ||
| Acquired during the period | 126,800,000 | ||
| Foreign exchange impact | (10,700,000) | ||
| Balance - 31 March 2019 | 116,100,000 | 0 | |
| Other | 7,400,000 | 7,400,000 | |
| Europe Building Products | |||
| Goodwill [Roll Forward] | |||
| Balance - 31 March 2019 | 200,800,000 | ||
| Asia Pacific | |||
| Goodwill [Roll Forward] | |||
| Balance - 31 March 2018 | 300,000 | ||
| Balance - 31 March 2019 | 300,000 | 300,000 | |
| Other Businesses | |||
| Goodwill [Roll Forward] | |||
| Balance - 31 March 2018 | 4,600,000 | ||
| Impairment | $ (4,600,000) | 0 | $ 0 |
| Balance - 31 March 2019 | $ 4,600,000 | ||
| X | ||||||||||
- 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://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- 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 Amount of loss from the write-down of an asset representing the future economic benefits arising 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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- Definition Amount of foreign currency translation gain (loss) which increases (decreases) an asset, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit to fair value. No definition available.
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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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- Definition Carrying amount (original costs adjusted for previously recognized amortization and impairment) as of the balance sheet date for the rights acquired through registration of a trade name to gain or protect exclusive use thereof for a projected indefinite period of benefit. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of increase in assets, excluding financial assets and goodwill, lacking physical substance with an indefinite life, from an acquisition. No definition available.
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- Definition Amount after impairment of indefinite-lived intangible assets classified as other. Excludes financial assets and goodwill. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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