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v3.19.1

Goodwill and Other Intangible Assets - Rollforward of Finite-Lived Assets (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Mar. 31, 2019 | Mar. 31, 2018 | Mar. 31, 2017
Finite-lived Intangible Assets [Roll Forward] |  |  |
Amortization | $ (6.1) | $ (0.9) | $ (0.8)
Impairment | (2.6) | 0.0 | $ 0.0
Other intangible assets [Member] |  |  |
Finite-lived Intangible Assets [Roll Forward] |  |  |
Balance - 31 March 2018 | 9.7 |  |
Beginning Balance, Accumulated Amortization | (4.8) |  |
Beginning Balance, Net | 4.9 |  |
Acquired during the period | 2.4 |  |
Amortization | (1.3) |  |
Impairment | (2.6) |  |
Foreign exchange impact | (0.3) |  |
Foreign exchange impact | 0.1 |  |
Foreign exchange impact | (0.2) |  |
Ending Balance, Net | 3.2 | 4.9 |
Ending Balance, Accumulated Amortization | (8.6) | (4.8) |
Ending Balance, Gross | 11.8 | 9.7 |
Customer relationships [Member] |  |  |
Finite-lived Intangible Assets [Roll Forward] |  |  |
Balance - 31 March 2018 | 0.0 |  |
Beginning Balance, Accumulated Amortization | 0.0 |  |
Beginning Balance, Net | 0.0 |  |
Acquired during the period | 57.8 |  |
Amortization | (4.8) |  |
Foreign exchange impact | (5.8) |  |
Foreign exchange impact | 0.5 |  |
Foreign exchange impact | (5.3) |  |
Ending Balance, Net | 47.7 | 0.0 |
Ending Balance, Accumulated Amortization | (4.3) | 0.0 |
Ending Balance, Gross | 52.0 | $ 0.0 |
Other Businesses |  |  |
Finite-lived Intangible Assets [Roll Forward] |  |  |
Impairment | (2.2) |  |
North America Fiber Cement |  |  |
Finite-lived Intangible Assets [Roll Forward] |  |  |
Impairment | $ (0.4) |  |

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- Definition Finite-Lived Intangible Assets, Accumulated Amortization, Foreign Currency Translation Adjustment + References No definition available. + Details
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- Definition Finite-Lived Intangible Assets, Net, Foreign Currency Translation Adjustment + References No definition available. + Details
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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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274 + Details
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- Definition Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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- Definition Amount of foreign currency translation gain (loss) which increases (decreases) assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References No definition available. + Details
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- Definition Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 928 -SubTopic 340 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6473545&loc=d3e61844-108004 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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- Definition Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275 + Details
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