Acquisitions - Narrative (Pro forma Information) (Details) (USD $)	12 Months Ended
	Jan. 27, 2013 contingency	Mar. 20, 2012
Business Acquisition [Line Items]
Debt instrument, face amount		$ 350,000,000
Gennum
Business Acquisition [Line Items]
Pro forma adjustment, decrease in cost of goods sold	(39,400,000)
Pro forma adjustment, number of pre-acquisition contingencies settled	2
Pro forma adjustment, increase in operating expense due to settlement	4,200,000
Pro forma adjustment, decrease in amortization expense	(1,600,000)
Pro forma adjustment, decrease in income tax benefit	(23,400,000)
Pro forma adjustment, increase in interest expense	$ 1,700,000