Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plans - Changes in Company's Benefit Obligation, Plan Assets and Funded Status for Plan (Detail)

v3.21.1
Employee Benefit Plans - Changes in Company's Benefit Obligation, Plan Assets and Funded Status for Plan (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Mar. 31, 2019
Pension Plans, Defined Benefit [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligation at beginning of year $ 35,783 $ 34,149  
Service cost 461 496 $ 571
Interest cost 1,211 1,290 1,339
Actuarial loss (gain) 1,284 2,368  
Benefit payments (942) (1,100)  
Liability released through annuity purchase (1,477) (1,420)  
Projected benefit obligation at end of year 36,320 35,783 34,149
Change in fair value of plan assets      
Fair value of plan assets at beginning of year 39,243 38,416  
Actual return on plan assets 5,712 3,347  
Benefit payments (942) (1,100)  
Annuities purchased (1,477) (1,420)  
Fair value of plan assets at end of year 42,536 39,243 38,416
Funded status      
Funded status at end of year 6,216 3,460  
Amount recognized in the Consolidated Balance Sheets 6,216 3,460  
Other Postretirement Benefit Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Projected benefit obligation at beginning of year 634 682  
Interest cost 18 22 25
Actuarial loss (gain) (3) (3)  
Benefit payments (62) (67)  
Projected benefit obligation at end of year 587 634 $ 682
Change in fair value of plan assets      
Employer contribution 62 67  
Benefit payments (62) (67)  
Funded status      
Funded status at end of year (587) (634)  
Amount recognized in the Consolidated Balance Sheets $ (587) $ (634)