Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plans - Additional Information (Detail)

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Employee Benefit Plans - Additional Information (Detail) - USD ($)
 12 Months Ended
Mar. 31, 2024
Mar. 31, 2023
Mar. 31, 2022
Defined Benefit Plan Disclosure [Line Items]      
Employee's years of service and average earnings five highest consecutive calendar years of compensation in the ten-year period preceding retirement    
Accumulated benefit obligation $ 22,398,000 $ 23,784,000  
Contribution equal to employee salary deferral 100.00%    
Employer contribution description matching contributions equal to 100% of the first 3% of an employee's salary deferral and 50% of the next 2% percent of an employee’s salary deferral    
Contribution next to employee salary deferral 3.00%    
Contribution for additional employee salary deferral 50.00%    
Contribution additional next to employee salary deferral 2.00%    
Share of the medical premium cost for family coverage $ 4,000    
Share of the medical premium cost for single coverage 2,000    
Share of the medical premium both family and single coverage for regular retirees $ 1,000    
Medical care cost trend rate 4.50%    
Medical care trend year 2028    
Medical care cost trend rate decrements 0.50%    
Current portion of accrued postretirement benefit obligation $ 49,000 49,000  
Defined Contribution Plan 401K [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Contributions to defined contribution plan 1,914,000 1,904,000 $ 1,365,000
Pension Plans, Defined Benefit [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Contributions expected during fiscal 2021 0    
Liability released through annuity purchase 1,452,000 1,383,000  
Annuities purchased 1,452,000 1,383,000  
Pension expense $ 556,000 $ (18,000) $ (538,000)
Weighted average discount rates used to develop net postretirement benefit cost 5.03% 3.66% 3.21%
Weighted average rate of increase in compensation levels 3.00% 3.00% 3.00%
Projected benefit obligation $ 25,042,000 $ 26,646,000 $ 32,991,000
Net actuarial (gain) loss recognized in accumulated other comprehensive loss, net of income tax 6,847,000 7,506,000  
Defined Contribution Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Contributions to defined contribution plan 1,237,000 1,030,000 710,000
Supplemental Executive Retirement Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Pension expense $ 54,000 $ 74,000 $ 346,000
Weighted average discount rates used to develop net postretirement benefit cost 5.01% 3.64% 3.21%
Weighted average rate of increase in compensation levels 3.00% 3.00% 3.00%
Projected benefit obligation $ 1,060,000 $ 1,104,000  
Net actuarial (gain) loss recognized in accumulated other comprehensive loss, net of income tax (69,000) (47,000)  
Other Postretirement Benefit Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Pension expense $ 15,000 $ 27,000 $ 38,000
Weighted average discount rates used to develop net postretirement benefit cost 4.76% 3.32% 2.34%
Projected benefit obligation $ 311,000 $ 355,000 $ 478,000
Net actuarial (gain) loss recognized in accumulated other comprehensive loss, net of income tax $ (2,000) $ 11,000