Goodwill and Intangible Assets - Future Amortization Expense For Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	Oct. 26, 2014		Jan. 26, 2014
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Remaining three months of fiscal year 2015	$ 6,881
Fiscal year 2016	26,954
Fiscal year 2017	26,094
Fiscal year 2018	25,049
Fiscal year 2019	21,507
Thereafter	10,933
Net carrying amount	117,418		136,944
Core Technologies [Member]
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Remaining three months of fiscal year 2015	5,231
Fiscal year 2016	20,919
Fiscal year 2017	20,919
Fiscal year 2018	20,919
Fiscal year 2019	17,507
Thereafter	10,385
Net carrying amount	95,880		111,568
Customer Relationships [Member]
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Remaining three months of fiscal year 2015	1,038
Fiscal year 2016	4,149
Fiscal year 2017	4,149
Fiscal year 2018	4,130
Fiscal year 2019	4,000
Thereafter	548
Net carrying amount	18,014		21,125
Technology Licenses [Member]
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Remaining three months of fiscal year 2015	455
Fiscal year 2016	1,798
Fiscal year 2017	1,026
Fiscal year 2018	0
Fiscal year 2019	0
Thereafter	0
Net carrying amount	3,279	[1]	3,475	[1]
Other Intangible Assets [Member]
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Remaining three months of fiscal year 2015	157
Fiscal year 2016	88
Fiscal year 2017	0
Fiscal year 2018	0
Fiscal year 2019	0
Thereafter	0
Net carrying amount	$ 245		$ 776

[1] Technology licenses relate to end-license agreements for intellectual property that is used by the Company in research and development activities and also has alternative future uses. Amortization expense related to technology licenses is reported as “Product development and engineering” in the condensed consolidated statements of income.