Employee Benefit Plans - Weighted-Average Assumptions used to Determine Benefit Obligations (Detail)	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Postretirement Benefits
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Discount rate	3.60%	3.30%
Pension Plan
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Discount rate	3.50%	3.50%