Deferred Revenue and Warranty Reserve - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	Jul. 28, 2012	Jan. 28, 2012	Jul. 30, 2011
Deferred Revenue and Warranty Reserve [Line Items]
Current portion of deferred direct costs	$ 21.2	$ 20.2	$ 19.3
Long-term portion of deferred direct costs	$ 53.7	$ 52.8	$ 50.4