Reclassified Amounts in Condensed Consolidated Statement of Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2011	Oct. 31, 2010
Revenues	$ 250,508	$ 238,937	$ 694,283	$ 607,448
Cost of revenues
System and software	10,864	14,261	41,235	28,881
Service and support	27,621	25,430	79,676	72,230
Amortization of purchased technology	1,761	3,299	7,872	10,428
Total cost of revenues	40,246	42,990	128,783	111,539
Gross margin	210,262	195,947	565,500	495,909
Operating expenses:
Research and development	81,305	73,622	220,578	208,058
Marketing and selling	83,036	80,591	236,718	225,135
General and administration	17,922	18,485	52,055	55,527
Equity in losses (earnings) of Frontline	134	(415)	(2,022)	(1,761)
Amortization of intangible assets	1,296	1,445	4,361	5,742
Special charges	1,164	1,578	7,388	8,052
Total operating expenses	184,857	175,306	519,078	500,753
Operating income (loss)	25,405	20,641	46,422	(4,844)
As Originally Reported
Revenues		238,937		607,448
Cost of revenues
System and software		11,218		20,409
Service and support		24,445		69,511
Amortization of purchased technology		3,299		10,428
Total cost of revenues		38,962		100,348
Gross margin		199,975		507,100
Operating expenses:
Research and development		70,727		199,904
Marketing and selling		82,603		230,889
General and administration		23,396		69,118
Equity in losses (earnings) of Frontline		(415)		(1,761)
Amortization of intangible assets		1,445		5,742
Special charges		1,578		8,052
Total operating expenses		179,334		511,944
Operating income (loss)		$ 20,641		$ (4,844)