Goodwill and Intangible Assets - Schedule Of Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands		3 Months Ended
		Apr. 30, 2017	Jan. 29, 2017
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount		$ 175,060	$ 175,060
Accumulated amortization		(119,573)	(113,287)
Net carrying amount		55,487	61,773
Core Technologies [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount		144,930	144,930
Accumulated amortization		(98,126)	(92,940)
Net carrying amount		$ 46,804	51,990
Core Technologies [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life		5 years
Core Technologies [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life		8 years
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount		$ 30,030	30,030
Accumulated amortization		(21,347)	(20,247)
Net carrying amount		$ 8,683	9,783
Customer Relationships [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life		5 years
Customer Relationships [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life		10 years
Technology Licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	[1]	2 years
Gross carrying amount	[1]	$ 100	100
Accumulated amortization	[1]	(100)	(100)
Net carrying amount	[1]	$ 0	$ 0

[1] Technology licenses relate to licensing agreements entered into by the Company that are used in research and development activities and have alternative future uses. Amortization expense related to technology licenses is reported as "Product development and engineering" in the Statements of Income.