Goodwill and Other Intangible Assets Goodwill and Other Intangible Assets (Details) - USD ($) $ in Millions |
12 Months Ended | ||
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Mar. 31, 2019 |
Mar. 31, 2018 |
Mar. 31, 2017 |
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| Goodwill [Line Items] | |||
| Amortization | $ 6.1 | $ 0.9 | $ 0.8 |
| Impairment | 2.6 | $ 0.0 | $ 0.0 |
| Other Businesses | |||
| Goodwill [Line Items] | |||
| Impairment | 2.2 | ||
| North America Fiber Cement | |||
| Goodwill [Line Items] | |||
| Impairment | $ 0.4 | ||
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- Definition The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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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 amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of a finite-lived intangible asset to fair value. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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