Schedule of Carrying Value of Trust Assets, Including Unrealized Gains or Losses (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Compensation And Retirement Disclosure [Abstract]
Investments held in Rabbi Trust	$ 8,811	$ 9,915
Unrealized (loss) gains in carrying value of trust assets	(208)	235
Unrealized (loss) gains in carrying value of trust assets are net of income tax expense of	(168)	126
Obligations under the supplemental plan	$ 25,072	$ 25,510