Short-Term and Long-Term Investments (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Oct. 31, 2014	Oct. 31, 2013
Long Term Investments
Amortized Cost	$ 190,192
U.S. government obligations	190,262us-gaap_AvailableForSaleSecurities
Extinguishment of Debt Disclosures [Abstract]
Amortized cost of debt maturities due in less than one year	140,176
Amortized cost of debt maturities due in one to two years	50,016
Amortized Cost	190,192
Estimated fair value of debt maturities due in less than one year	140,205
Estimated fair value of debt maturities due in one to two years	50,057
Estimated Fair Value	190,262us-gaap_AvailableForSaleSecurities
U.S. government obligations
Long Term Investments
Amortized Cost	160,198	114,970
Gross Unrealized Gains	70	46
Gross Unrealized Losses	0	0
U.S. government obligations	160,268	115,016
Extinguishment of Debt Disclosures [Abstract]
Amortized Cost	160,198	114,970
Estimated Fair Value	160,268	115,016
Commercial Paper
Long Term Investments
Amortized Cost	29,994	24,994
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
U.S. government obligations	29,994	24,994
Extinguishment of Debt Disclosures [Abstract]
Amortized Cost	29,994	24,994
Estimated Fair Value	29,994	24,994
Short-term Investments \| U.S. government obligations
Long Term Investments
Amortized Cost	110,182	99,974
Gross Unrealized Gains	29	11
Gross Unrealized Losses	0	0
U.S. government obligations	110,211	99,985
Extinguishment of Debt Disclosures [Abstract]
Amortized Cost	110,182	99,974
Estimated Fair Value	110,211	99,985
Short-term Investments \| Commercial Paper
Long Term Investments
Amortized Cost	29,994	24,994
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
U.S. government obligations	29,994	24,994
Extinguishment of Debt Disclosures [Abstract]
Amortized Cost	29,994	24,994
Estimated Fair Value	29,994	24,994
Other Long-term Investments \| U.S. government obligations
Long Term Investments
Amortized Cost	50,016	14,996
Gross Unrealized Gains	41	35
Gross Unrealized Losses	0	0
U.S. government obligations	50,057	15,031
Extinguishment of Debt Disclosures [Abstract]
Amortized Cost	50,016	14,996
Estimated Fair Value	$ 50,057	$ 15,031

This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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