Business Combinations (Narrative) (Details) (USD $)			12 Months Ended	3 Months Ended	12 Months Ended		3 Months Ended	12 Months Ended		3 Months Ended		12 Months Ended	3 Months Ended
	Apr. 30, 2012	Jan. 31, 2012	Jan. 31, 2012 Verint [Member] Business_Acquisitions	Apr. 30, 2012 Verint [Member] Vovici Acquisition [Member]	Jan. 31, 2012 Verint [Member] Vovici Acquisition [Member]	Aug. 04, 2011 Verint [Member] Vovici Acquisition [Member]	Apr. 30, 2012 Verint [Member] Global Management Technologies Acquisition [Member]	Jan. 31, 2012 Verint [Member] Global Management Technologies Acquisition [Member]	Oct. 07, 2011 Verint [Member] Global Management Technologies Acquisition [Member]	Apr. 30, 2012 Verint [Member] Other Acquisitions [Member]	Apr. 30, 2011 Verint [Member] Other Acquisitions [Member]	Jan. 31, 2012 Verint [Member] Other Acquisitions [Member]	Apr. 30, 2012 Verint [Member] Other Acquisitions [Member] Developed Technology Rights [Member]	Apr. 30, 2012 Verint [Member] Other Acquisitions [Member] Customer Relationships [Member]	Apr. 30, 2011 Verint [Member] Iontas Acquisition [Member]	Jan. 31, 2012 Verint [Member] Iontas Acquisition [Member]
Business Acquisition [Line Items]
Cash consideration				$ 55,708,000		$ 66,100,000			$ 36,600,000	$ 33,835,000
Fair value of contingent consideration	33,900,000	38,646,000		(9,900,000)		9,900,000			12,000,000	(20,504,000)		20,500,000				1,700,000
Potential additional contingent payments						19,100,000			17,400,000			41,000,000
Recorded benefit from change in fair value of contingent consideration				300,000			3,600,000			300,000
Changes in fair value of contingent consideration recorded within selling, general and administrative expenses				7,500,000	7,200,000		6,000,000	9,600,000		20,400,000	1,900,000	20,100,000			100,000
Transaction and related costs to acquisitions				200,000			200,000			300,000
Total consideration for additional business combinations				66,103,000						55,155,000		55,200,000
Number of additional businesses acquired			5
Number of acquisitions of assets transactions qualifying as business combinations			2
Goodwill				41,502,000						30,537,000		21,400,000
Change in goodwill due to fluctuations in foreign currency exchange rates										17,000,000
Goodwill being assessed for tax deductibility										6,900,000
Goodwill not deductible for tax purposes										10,100,000
Current liabilities										3,600,000		4,000,000
Noncurrent liabilities										4,300,000		4,700,000
Liabilities assumed, value adjustment				200,000
Decrease in fair value of intangible assets													300,000	400,000
Decrease in fair value of deferred income tax liabilities										3,800,000
Goodwill, purchase price allocation adjustment related to intangible assets										3,100,000
Goodwill, purchase price allocation adjustments, total										(100,000)		(2,900,000)
Purchase price allocation adjustment for intangible assets net												(600,000)
Purchase price allocation adjustment for accounts payable and accrued expenses												(200,000)
Purchase price allocation adjustment for long-term deferred income tax liabilities												(3,100,000)
Purchase price allocation adjustment for long-term deferred tax assets												$ 200,000