Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plans - Weighted Average Actuarial Assumptions Used to Determine Net Pension Cost (Detail)

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Employee Benefit Plans - Weighted Average Actuarial Assumptions Used to Determine Net Pension Cost (Detail) - Pension Plans, Defined Benefit [Member]
12 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Mar. 31, 2018
Defined Benefit Plan Disclosure [Line Items]      
Discount rate 3.83% 3.95% 4.08%
Rate of increase in compensation levels 3.00% 3.00% 3.00%
Long-term rate of return on plan assets 7.00% 8.00% 8.00%