Quartely Summary (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 25, 2015	Oct. 26, 2014	Jul. 27, 2014	Apr. 27, 2014	Jan. 26, 2014	Oct. 27, 2013	Jul. 28, 2013	Apr. 28, 2013	Jan. 25, 2015	Jan. 26, 2014	Jan. 27, 2013
Selected Quarterly Financial Information [Abstract]
Revenue	$ 1,250,514	$ 1,225,382	$ 1,102,824	$ 1,102,787	$ 1,144,218	$ 1,053,967	$ 977,238	$ 954,739	$ 4,681,507	$ 4,130,162	$ 4,280,159
Cost of revenue	550,911	548,684	483,850	498,585	524,976	469,552	431,700	436,171	2,082,030	1,862,399	2,053,816
Gross profit	699,603	676,698	618,974	604,202	619,242	584,415	545,538	518,568	2,599,477	2,267,763	2,226,343
Net income	$ 193,128	$ 172,967	$ 127,976	$ 136,516	$ 146,917	$ 118,734	$ 96,448	$ 77,891	$ 630,587	$ 439,990	$ 562,536
Basic net income per share	$ 0.35	$ 0.32	$ 0.23	$ 0.24	$ 0.26	$ 0.20	$ 0.16	$ 0.13	$ 1.14	$ 0.75	$ 0.91
Diluted net income per share	$ 0.35	$ 0.31	$ 0.22	$ 0.24	$ 0.25	$ 0.20	$ 0.16	$ 0.13	$ 1.12	$ 0.74	$ 0.90