Reclassified Amounts in Condensed Consolidated Statement of Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2011	Jan. 31, 2011	Oct. 31, 2010	Jul. 31, 2010	Apr. 30, 2010	Jan. 31, 2012	Jan. 31, 2011	Jan. 31, 2010
Revenues									$ 1,014,638	$ 914,753	$ 802,727
Cost of revenues
System and software									54,972	42,865	33,835
Service and support									108,690	99,612	88,704
Amortization of purchased technology									9,796	13,771	12,012
Total cost of revenues									173,458	156,248	134,551
Gross margin	275,680	210,262	169,848	185,390	262,596	195,947	152,764	147,198	841,180	758,505	668,176
Operating expenses:
Research and development									310,758	296,631	264,051
Marketing and selling									326,608	312,834	297,718
General and administration									74,811	80,948	75,056
Equity in earnings of Frontline									(2,268)	(2,051)
Amortization of intangible assets									5,905	7,347	11,184
Special charges									13,174	10,257	21,334
Total operating expenses									728,988	705,966	669,343
Operating income (loss)	65,770	25,405	4,844	16,173	57,383	20,641	(10,491)	(14,994)	112,192	52,539	(1,167)
As Originally Reported
Revenues										914,753	802,727
Cost of revenues
System and software										31,119	22,592
Service and support										95,715	85,265
Amortization of purchased technology										13,771	12,012
Total cost of revenues										140,605	119,869
Gross margin										774,148	682,858
Operating expenses:
Research and development										284,851	255,538
Marketing and selling										320,825	303,709
General and administration										100,380	92,260
Equity in earnings of Frontline										(2,051)
Amortization of intangible assets										7,347	11,184
Special charges										10,257	21,334
Total operating expenses										721,609	684,025
Operating income (loss)										$ 52,539	$ (1,167)