Intangible Assets Acquired Through Business Combinations and Goodwill (Intangible Assets Acquired From Business Combinations) (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross	$ 2,005,224	$ 1,154,088
Additions	851,136
Accumulated Amortization	(891,850)	(664,082)
Expense	(227,768)	(161,700)	$ (155,000)
Intangible Assets, Net	$ 1,113,374	490,006
Weighted Average Useful Life	4 years 6 months
Developed Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross	$ 1,092,161	684,260
Additions	407,901
Accumulated Amortization	(577,929)	(451,889)
Expense	(126,040)
Intangible Assets, Net	$ 514,232	232,371
Weighted Average Useful Life	3 years 7 months 6 days
Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross	$ 843,614	410,763
Additions	432,851
Accumulated Amortization	(254,035)	(160,866)
Expense	(93,169)
Intangible Assets, Net	$ 589,579	249,897
Weighted Average Useful Life	5 years 4 months 24 days
Trademarks and Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross	$ 45,950	38,980
Additions	6,970
Accumulated Amortization	(41,349)	(38,980)
Expense	(2,369)
Intangible Assets, Net	$ 4,601	0
Weighted Average Useful Life	2 years 3 months 18 days
Territory Rights and Other [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross	$ 15,786	12,372
Additions	3,414
Accumulated Amortization	(12,256)	(8,585)
Expense	(3,671)
Intangible Assets, Net	$ 3,530	3,787
Weighted Average Useful Life	7 years 3 months 18 days
Fremont 50 Lease Intangibles [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross	$ 7,713	7,713
Additions	0
Accumulated Amortization	(6,281)	(3,762)
Expense	(2,519)
Intangible Assets, Net	$ 1,432	$ 3,951
Weighted Average Useful Life	2 years 1 month 6 days