Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2014	Oct. 31, 2013
Operating activities:
Net loss	$ (38,924)	$ (124,434)	$ (196,923)	$ (115,552)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	111,954	114,347	330,358	254,610
Amortization of debt discount and transaction costs	9,420	13,343	31,160	36,207
Gain on sales of land and building improvements	(15,625)	0	(15,625)	0
Loss on conversions of convertible senior notes	1,340	0	10,230	0
Amortization of deferred commissions	65,371	48,008	186,526	139,864
Expenses related to employee stock plans	139,460	141,536	412,963	366,741
Excess tax benefits from employee stock plans	(1,221)	(1,578)	(3,447)	(2,166)
Changes in assets and liabilities, net of business combinations:
Accounts receivable, net	39,792	(4,502)	566,306	332,090
Deferred commissions	(64,280)	(57,968)	(171,022)	(120,798)
Prepaid expenses and other current assets and other assets	6,588	23,822	34,501	14,542
Accounts payable, accrued expenses and other liabilities	(1,933)	40,404	(44,894)	(126,154)
Deferred revenue	(129,431)	(55,119)	(298,642)	(175,153)
Net cash provided by operating activities	122,511	137,859	841,491	604,231
Investing activities:
Business combinations, net of cash acquired	38,071	0	38,071	(2,614,732)
Proceeds from land activity, net	192,240	0	223,240	0
Deposit for purchase of building and land	(114,935)	0	(114,935)	0
Strategic investments	(12,852)	(9,017)	(47,905)	(17,831)
Purchases of marketable securities	(154,560)	(99,050)	(690,024)	(419,795)
Sales of marketable securities	46,908	16,820	197,293	1,022,470
Maturities of marketable securities	22,288	427	46,248	21,031
Capital expenditures	(73,426)	(72,702)	(205,100)	(229,261)
Net cash used in investing activities	(56,266)	(163,522)	(553,112)	(2,238,118)
Financing activities:
Proceeds from borrowings on convertible senior notes, net	0	0	0	1,132,750
Proceeds from issuance of warrants	0	0	0	84,800
Purchase of convertible note hedge	0	0	0	(153,800)
Proceeds from term loan, net	0	0	0	298,500
Proceeds from revolving credit facility, net	297,325	0	297,325	0
Proceeds from employee stock plans	91,337	110,710	226,561	217,429
Excess tax benefits from employee stock plans	1,221	1,578	3,447	2,166
Payments on convertible senior notes	(89,645)	0	(387,229)	0
Principal payments on capital lease obligations	(10,345)	(12,440)	(61,280)	(33,047)
Payments on term loan	(270,000)	(7,500)	(285,000)	(7,500)
Net cash provided by (used in) financing activities	19,893	92,348	(206,176)	1,541,298
Effect of exchange rate changes	(14,538)	5,184	(17,513)	(2,906)
Net increase (decrease) in cash and cash equivalents	71,600	71,869	64,690	(95,495)
Cash and cash equivalents, beginning of period	774,725	579,881	781,635	747,245
Cash and cash equivalents, end of period	846,325	651,750	846,325	651,750
Cash paid during the period for:
Interest	4,285	7,200	21,274	12,391
Income taxes, net of tax refunds	6,187	6,105	30,986	25,626
Non-cash financing and investing activities:
Fixed assets acquired under capital leases	38,604	13,857	119,939	487,531
Building in progress - leased facility acquired under financing obligation	29,756	0	62,804	0
Fair value of equity awards assumed	$ 1,050	$ 0	$ 1,050	$ 19,037
Fair value of common stock issued as consideration for business combinations	338,033	0	338,033	0