Fair Value Measurements (Details) (USD $)	12 Months Ended
Oct. 31, 2014	Oct. 31, 2013
Assets:
U.S. government obligations	$ 190,262,000us-gaap_AvailableForSaleSecurities
Embedded redemption feature	0	2,740,000
Reconciliation of changes in Level 3 fair value measurements
Balance at October 31, 2013	2,740,000
Issuances	0
Settlements	0
Changes in unrealized loss	(2,740,000)
Transfers into Level 3	0
Transfers out of Level 3	0
Balance at October 31, 2014	0
Fair Value, Measurements, Recurring \| Level 1
Assets:
Money market funds	440,013,000	254,330,000
U.S. government obligations	0	0
Commercial paper	0	0
Foreign currency forward contracts	0
Embedded redemption feature		0
Total assets measured at fair value	440,013,000	254,330,000
Liabilities:
Foreign currency forward contracts		0
Total liabilities measured at fair value	0	0
Fair Value, Measurements, Recurring \| Level 2
Assets:
Money market funds	0	0
U.S. government obligations	160,268,000	115,016,000
Commercial paper	89,989,000	44,991,000
Foreign currency forward contracts	1,561,000
Embedded redemption feature		0
Total assets measured at fair value	251,818,000	160,007,000
Liabilities:
Foreign currency forward contracts		442,000
Total liabilities measured at fair value	2,283,000	442,000
Fair Value, Measurements, Recurring \| Level 3
Assets:
Money market funds	0	0
U.S. government obligations	0	0
Commercial paper	0	0
Foreign currency forward contracts	0
Embedded redemption feature		2,740,000
Total assets measured at fair value	0	2,740,000
Liabilities:
Foreign currency forward contracts		0
Total liabilities measured at fair value	0	0
Fair Value, Measurements, Recurring \| Total
Assets:
Money market funds	440,013,000	254,330,000
U.S. government obligations	160,268,000	115,016,000
Commercial paper	89,989,000	44,991,000
Foreign currency forward contracts	1,561,000
Embedded redemption feature		2,740,000
Total assets measured at fair value	691,831,000	417,077,000
Liabilities:
Foreign currency forward contracts		442,000
Total liabilities measured at fair value	2,283,000	442,000
Foreign Exchange Forward \| Fair Value, Measurements, Recurring \| Level 1
Liabilities:
Foreign currency forward contracts	0
Foreign Exchange Forward \| Fair Value, Measurements, Recurring \| Level 2
Liabilities:
Foreign currency forward contracts	200,000
Foreign Exchange Forward \| Fair Value, Measurements, Recurring \| Level 3
Liabilities:
Foreign currency forward contracts	0
Foreign Exchange Forward \| Fair Value, Measurements, Recurring \| Total
Liabilities:
Foreign currency forward contracts	200,000
Designated as Hedging Instrument \| Cash Flow Hedging \| Interest Rate Swap \| Fair Value, Measurements, Recurring \| Level 1
Liabilities:
Foreign currency forward contracts	0
Designated as Hedging Instrument \| Cash Flow Hedging \| Interest Rate Swap \| Fair Value, Measurements, Recurring \| Level 2
Liabilities:
Foreign currency forward contracts	2,083,000
Designated as Hedging Instrument \| Cash Flow Hedging \| Interest Rate Swap \| Fair Value, Measurements, Recurring \| Level 3
Liabilities:
Foreign currency forward contracts	0
Designated as Hedging Instrument \| Cash Flow Hedging \| Interest Rate Swap \| Fair Value, Measurements, Recurring \| Total
Liabilities:
Foreign currency forward contracts	$ 2,083,000

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Amount of gain (loss) recognized in the income statement for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of issuances of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy.

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Fair value of financial and nonfinancial obligations.

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