Accounts and Other Receivables - Provision for Doubtful Trade Debts (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2019 |
Mar. 31, 2018 |
Mar. 31, 2017 |
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| Allowance for Doubtful Accounts Receivable [Roll Forward] | |||
| Balance at beginning of period | $ 1.3 | $ 0.9 | $ 1.1 |
| Adjustment to provision | 2.8 | 0.6 | (0.1) |
| Write-offs, net of recoveries | (1.2) | (0.2) | (0.1) |
| Balance at end of period | $ 2.9 | $ 1.3 | $ 0.9 |
| X | ||||||||||
- Definition A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Amount of increase (decrease) in the allowance for doubtful accounts. No definition available.
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| X | ||||||||||
- 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 direct write-downs of accounts receivable charged against the allowance. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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