Supplemental Cash Flow Information - Supplemental Noncash Investing and Financing Activities (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Other Significant Noncash Transactions [Line Items]
Issuance of Common Stock under the Employee Profit Sharing and Retirement Savings Plan	$ 3,150	$ 4,500	$ 5,000