Retirement Plans - Summary Changes in Plan Assets and Benefit Obligations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	$ 0	$ 0	$ 0
Changes in plan assets and benefit obligations:
Net loss (gain) arising during the year	(1,953)	5,485	(988)
Effect of exchange rates on amounts included in AOCI	3,019	(2,275)	142
Amounts recognized as a component of net periodic benefit costs:
Amortization of prior service cost	(46)	(42)	(382)
Amortization or settlement recognition of net loss	(1,725)	(1,389)	(1,661)
Total recognized in other comprehensive income	$ (705)	$ 1,779	$ (2,889)