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v3.19.1

Stock-Based Compensation - Schedule of Stock-Based Compensation Expense (Detail) - USD ($) $ in Millions | 12 Months Ended
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Mar. 31, 2019 | Mar. 31, 2018 | Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] |  |  |
Total stock-based compensation expense | $ 11.9 | $ 16.7 | $ 14.7
Liability Awards Expense [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] |  |  |
Total stock-based compensation expense | (0.6) | 5.6 | 5.4
Equity Awards Expense [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] |  |  |
Total stock-based compensation expense | $ 12.5 | $ 11.1 | $ 9.3

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- Definition Amount of expense for employee benefit and equity-based compensation. + References No definition available. + Details
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Balance Type: | debit
Period Type: | duration

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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. + References No definition available. + Details
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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |