Employee Benefit Plans - Components of Net Periodic Benefit Cost (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 23	$ 30
Amortization of net loss		30
Total net periodic benefit cost	23	60
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Interest cost	108	115
Total net periodic benefit cost	$ 108	$ 115