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Stock-Based Compensation - Schedule of Stock-Based Compensation Expense (Detail) - USD ($) $ in Millions | 12 Months Ended
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Mar. 31, 2017 | Mar. 31, 2016 | Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] |  |  |
Total stock-based compensation expense | $ 14.7 | $ 15.1 | $ 12.5
Liability Awards Expense [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] |  |  |
Total stock-based compensation expense | 5.4 | 4.8 | 3.3
Equity Awards Expense [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] |  |  |
Total stock-based compensation expense | $ 9.3 | $ 10.3 | $ 9.2

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- Definition Costs and payments related to employee benefits and equity-based compensation, such as pension expense and contributions, other postretirement benefits expense and payments, stock or unit options expense, and amortization of restricted stock or unit. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585 + Details
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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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