Useful Lives of Property and Equipment (Detail)	6 Months Ended
	Sep. 30, 2012
Buildings | Minimum
Property, Plant and Equipment [Line Items]
Useful lives of property and equipment	30 years
Buildings | Maximum
Property, Plant and Equipment [Line Items]
Useful lives of property and equipment	35 years
Machinery, equipment and automobiles | Minimum
Property, Plant and Equipment [Line Items]
Useful lives of property and equipment	7 years
Machinery, equipment and automobiles | Maximum
Property, Plant and Equipment [Line Items]
Useful lives of property and equipment	15 years
Furniture and Fixtures [Member] | Minimum
Property, Plant and Equipment [Line Items]
Useful lives of property and equipment	7 years
Furniture and Fixtures [Member] | Maximum
Property, Plant and Equipment [Line Items]
Useful lives of property and equipment	10 years