Merger-related Costs (Detail) (USD $) In Thousands	3 Months Ended	6 Months Ended
	Jul. 31, 2010	Jul. 30, 2011	Jul. 31, 2010
Business Acquisition [Line Items]
Merger-related costs	$ 3,050	$ 885	$ 26,863
Investment banking
Business Acquisition [Line Items]
Merger-related costs			14,255
Accounting and legal
Business Acquisition [Line Items]
Merger-related costs	1,669		6,650
Financing incentive compensation
Business Acquisition [Line Items]
Merger-related costs	1,210	885	4,428
Other costs
Business Acquisition [Line Items]
Merger-related costs	$ 171		$ 1,530