Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plans - Summary of Increase (Decrease) in Accumulated Other Comprehensive Loss, Net of Income Tax (Detail)

v3.20.1
Employee Benefit Plans - Summary of Increase (Decrease) in Accumulated Other Comprehensive Loss, Net of Income Tax (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Mar. 31, 2018
Defined Benefit Plan Disclosure [Line Items]      
Total $ 525 $ 348 $ (1,668)
Pension Plans, Defined Benefit [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Net actuarial loss arising during the year 1,298 1,080  
Amortization of actuarial loss (750) (712)  
Total 548 368  
Other Postretirement Benefit Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Net actuarial loss arising during the year (2) 1  
Amortization of actuarial loss (21) (21)  
Total $ (23) $ (20)