Business Combinations (Narrative) (Details) (USD $)	3 Months Ended	6 Months Ended
	Apr. 30, 2012	Apr. 30, 2012	Feb. 22, 2012
Magma Corporation [Member]
Business Acquisition [Line Items]
Acquisition price per share			$ 7.35
Acquisition-related costs	$ 30,200,000	$ 31,800,000
Acquisition cost recorded to general and administrative expense	14,400,000	16,000,000
Acquisition cost recorded to sales and marketing expense	7,900,000	7,900,000
Acquisition cost recorded to research and development expense	6,400,000	6,400,000
Acquisition cost recorded to cost of revenue	1,500,000	1,500,000
Total fair value of stock awards assumed	22,200,000	22,200,000
Fair value of assumed equity awards allocated to purchase consideration			6,797,000
Fair value of assumed stock awards allocated for future services	15,400,000	15,400,000
Total purchase consideration			550,234,000
Goodwill arising from acquisition			303,481,000
Identifiable intangibles assets acquired			184,300,000
Magma Corporation [Member] | Maximum [Member]
Business Acquisition [Line Items]
Definite lived intangible asset amortization period		10
Magma Corporation [Member] | Minimum [Member]
Business Acquisition [Line Items]
Definite lived intangible asset amortization period		3
Other Fiscal 2012 Acquisitions [Member]
Business Acquisition [Line Items]
Acquisition-related costs	400,000	1,600,000
Total purchase consideration	55,800,000	55,800,000
Acquired goodwill expected to be deductible for tax purposes	11,800,000	11,800,000
Goodwill arising from acquisition	36,900,000	36,900,000
Identifiable intangibles assets acquired	$ 26,000,000	$ 26,000,000
Other Fiscal 2012 Acquisitions [Member] | Maximum [Member]
Business Acquisition [Line Items]
Definite lived intangible asset amortization period		8
Other Fiscal 2012 Acquisitions [Member] | Minimum [Member]
Business Acquisition [Line Items]
Definite lived intangible asset amortization period		3