Components of Net Periodic Cost (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Compensation And Retirement Disclosure [Abstract]
Service Cost - Benefits Earned During the Period	$ 100	$ 153	$ 200	$ 404
Interest Cost of Projected Benefit Obligation	337	357	674	753
Expected Return on Plan Assets	(463)	(578)	(926)	(980)
Recognized Net Actuarial Loss	58	46	116	473
Amortization of Prior-Service Cost	15	60	30	150
Net Periodic Pension Cost	$ 47	$ 38	$ 94	$ 800