Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plans - Weighted Average Actuarial Assumptions Used to Develop Projected Benefit Obligation (Detail)

v2.4.0.8
Employee Benefit Plans - Weighted Average Actuarial Assumptions Used to Develop Projected Benefit Obligation (Detail) (Other Postretirement Benefit Plans [Member])
Mar. 31, 2014
Mar. 31, 2013
Other Postretirement Benefit Plans [Member]
   
Defined Benefit Plan Disclosure [Line Items]    
Discount rate 3.59% 3.26%
Medical care cost trend rate 8.00% 8.00%