| Description of Stock Plans - Stock Compensation Expense (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
|---|---|---|---|
| Mar. 31, 2021 | Mar. 31, 2020 | Mar. 31, 2019 | |
| General and administrative | |||
| Deferred Compensation Arrangement With Individual Share Based Payments [Line Items] | |||
| Allocated Stock compensation expense | $ 5,876 | $ 3,353 | $ 2,531 | 
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- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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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. No definition available. 
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- Details 
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