Fair Value Measurements (Details) - USD ($) $ in Thousands	Oct. 31, 2015	Oct. 31, 2014
Assets:
U.S. government obligations	$ 230,212
Fair Value, Measurements, Recurring
Assets:
Money market funds	642,073	$ 440,013
U.S. government obligations	205,223	160,268
Commercial paper	74,983	89,989
Foreign currency forward contracts	89	1,561
Total assets measured at fair value	922,368	691,831
Liabilities:
Foreign currency forward contracts		200
Total liabilities measured at fair value	6,034	2,283
Foreign Exchange Forward | Fair Value, Measurements, Recurring
Liabilities:
Foreign currency forward contracts	512
Interest Rate Swap | Designated as Hedging Instrument | Cash Flow Hedging | Fair Value, Measurements, Recurring
Liabilities:
Foreign currency forward contracts	5,522	2,083
Level 1 | Fair Value, Measurements, Recurring
Assets:
Money market funds	642,073	440,013
U.S. government obligations	0	0
Commercial paper	0	0
Foreign currency forward contracts	0	0
Total assets measured at fair value	642,073	440,013
Liabilities:
Foreign currency forward contracts		0
Total liabilities measured at fair value	0	0
Level 1 | Foreign Exchange Forward | Fair Value, Measurements, Recurring
Liabilities:
Foreign currency forward contracts	0
Level 1 | Interest Rate Swap | Designated as Hedging Instrument | Cash Flow Hedging | Fair Value, Measurements, Recurring
Liabilities:
Foreign currency forward contracts	0	0
Level 2 | Fair Value, Measurements, Recurring
Assets:
Money market funds	0	0
U.S. government obligations	205,223	160,268
Commercial paper	74,983	89,989
Foreign currency forward contracts	89	1,561
Total assets measured at fair value	280,295	251,818
Liabilities:
Foreign currency forward contracts		200
Total liabilities measured at fair value	6,034	2,283
Level 2 | Foreign Exchange Forward | Fair Value, Measurements, Recurring
Liabilities:
Foreign currency forward contracts	512
Level 2 | Interest Rate Swap | Designated as Hedging Instrument | Cash Flow Hedging | Fair Value, Measurements, Recurring
Liabilities:
Foreign currency forward contracts	5,522	2,083
Level 3 | Fair Value, Measurements, Recurring
Assets:
Money market funds	0	0
U.S. government obligations	0	0
Commercial paper	0	0
Foreign currency forward contracts	0	0
Total assets measured at fair value	0	0
Liabilities:
Foreign currency forward contracts		0
Total liabilities measured at fair value	0	0
Level 3 | Foreign Exchange Forward | Fair Value, Measurements, Recurring
Liabilities:
Foreign currency forward contracts	0
Level 3 | Interest Rate Swap | Designated as Hedging Instrument | Cash Flow Hedging | Fair Value, Measurements, Recurring
Liabilities:
Foreign currency forward contracts	$ 0	$ 0