Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plans - Components of Postretirement Benefit Cost (Income) and Pension (Benefit) Cost (Detail)

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Employee Benefit Plans - Components of Postretirement Benefit Cost (Income) and Pension (Benefit) Cost (Detail) - Pension Plans, Defined Benefit [Member] - USD ($)
$ in Thousands
12 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Mar. 31, 2014
Defined Benefit Plan Disclosure [Line Items]      
Service cost during the period $ 521 $ 546 $ 576
Interest cost on projected benefit obligation 1,437 1,434 1,359
Expected return on assets (3,181) (3,033) (2,728)
Unrecognized prior service cost   4 4
Actuarial loss 1,174 580 1,002
Net pension (benefit) cost $ (49) $ (469) $ 213