Summary of Significant Accounting Policies - Useful Lives within Property Classification (Detail)	12 Months Ended
	Jan. 31, 2013
Minimum [Member] | Buildings [Member]
Property, Plant and Equipment [Line Items]
Useful lives	15 years
Minimum [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Useful lives	3 years
Maximum [Member] | Buildings [Member]
Property, Plant and Equipment [Line Items]
Useful lives	35 years
Maximum [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Useful lives	10 years