Retirement Plans - Schedule of Net Pension (Benefit) Expense Recognized - Qualified Plan (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Curtailment benefit			$ (8,020)
Qualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefits earned during the period		$ 760	2,042	$ 2,280
Interest cost on projected benefit obligation	$ 642	628	2,024	1,884
Expected return on assets	(951)	(601)	(2,275)	(1,804)
Amortization of net prior service (benefit) cost		14	(28)	43
Curtailment benefit			(8,051)
Net pension (benefit) expense	$ (309)	$ 801	$ (6,288)	$ 2,403