Reconciliation of Federal Statutory Income Tax Rate to Effective Tax Rate (Detail)	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Income Tax Rate Reconciliation [Line Items]
Income Tax Expense at U.S. federal statutory rate	34.00%	34.00%
Benefit of tax deduction allowed to manufacturing companies	(3.00%)	(3.00%)
State and local income tax rates net of federal income tax benefit	1.90%	2.20%
Provision for income taxes	32.90%	33.20%