Acquisitions - Narrative (Details)	0 Months Ended		3 Months Ended	12 Months Ended
	Mar. 20, 2012 Gennum USD ($)	Mar. 20, 2012 Gennum CAD	Jan. 27, 2013 Gennum USD ($)	Jan. 26, 2014 Gennum USD ($)	Jan. 27, 2013 Gennum USD ($)	Oct. 28, 2012 Gennum USD ($)	May 27, 2012 Gennum USD ($)	Mar. 07, 2012 Cycleo USD ($)
Percentage of outstanding shares acquired	100.00%	100.00%
Price paid per share		13.55
Total acquisition consideration	$ 506,546,000
Long-term debt	347,000,000
Secured term loans, maturity term	5 years	5 years
Original issue discount on debt	3,000,000
Post-acquisition compensation expense				9,600,000
Goodwill decrease, purchase accounting adjustments			(900,000)
Purchase price allocation, goodwill	261,891,000		261,900,000		261,900,000	262,800,000
Transaction and integration expenses				1,700,000	24,800,000
Settled pre-acquisition contingencies related to legal matters							4,200,000
Cash paid for acquisition								5,000,000
Deferred compensation potential cash payment								$ 16,000,000