| Employee Benefit Plans - Weighted Average Actuarial Assumptions Used to Determine Benefit Obligation (Detail) - Pension Plans, Defined Benefit [Member] | Mar. 31, 2021 | Mar. 31, 2020 | 
|---|---|---|
| Defined Benefit Plan Disclosure [Line Items] | ||
| Discount rate | 3.21% | 3.44% | 
| Rate of increase in compensation levels | 3.00% | 3.00% | 
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- Definition Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Weighted average rate increase of compensation, used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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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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