Annual report pursuant to Section 13 and 15(d)

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

v3.7.0.1
Employee Benefit Plans - Summary of (Decrease) Increase in Accumulated Other Comprehensive Loss, Net of Income Tax (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Mar. 31, 2015
Defined Benefit Plan Disclosure [Line Items]      
Total $ (2,493) $ 1,470 $ 3,294
Pension Plans, Defined Benefit [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Net actuarial (gain) loss arising during the year (1,609) 2,280  
Amortization of actuarial loss (873) (759)  
Total (2,482) 1,521  
Other Postretirement Benefit Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Net actuarial (gain) loss arising during the year 13 (26)  
Amortization of actuarial loss (24) (25)  
Total $ (11) $ (51)