Summary of Significant Accounting Policies - Estimated Useful Lives of Property, Plant and Equipment (Detail)	12 Months Ended
	Jan. 31, 2013
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	39 years
Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years
Minimum [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Minimum [Member] | Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Minimum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	2 years
Maximum [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	15 years
Maximum [Member] | Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years
Maximum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years