| Accounts and Other Receivables - Provision for Doubtful Trade Debts (Details) - USD ($) $ in Millions | 12 Months Ended | ||
|---|---|---|---|
| Mar. 31, 2023 | Mar. 31, 2022 | Mar. 31, 2021 | |
| Allowance for Doubtful Accounts Receivable [Roll Forward] | |||
| Balance at beginning of period | $ 3.4 | $ 6.1 | $ 4.4 | 
| Adjustment to provision | (0.6) | (2.2) | 3.1 | 
| Write-offs, net of recoveries | (0.2) | (0.5) | (1.4) | 
| Balance at end of period | $ 2.6 | $ 3.4 | $ 6.1 | 
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- Definition Amount of allowance for credit loss on accounts receivable, classified as current. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount of increase (decrease) in allowance for credit loss on accounts receivable. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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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 direct write-downs of accounts receivable charged against the allowance. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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