Fair Value Measurements (Details 1) (Fair Value, Measurements, Recurring, USD $) In Thousands, unless otherwise specified	Jan. 31, 2015	Oct. 31, 2014
Assets:
Assets measured at fair value	$ 677,433	$ 691,831
Liabilities:
Total liabilities measured at fair value	9,889	2,283
Level 1
Assets:
Assets measured at fair value	411,477	440,013
Liabilities:
Total liabilities measured at fair value	0	0
Level 2
Assets:
Assets measured at fair value	265,956	251,818
Liabilities:
Total liabilities measured at fair value	9,889	2,283
Level 3
Assets:
Assets measured at fair value	0	0
Liabilities:
Total liabilities measured at fair value	0	0
Cash equivalents
Assets:
Assets measured at fair value	476,472	500,008
Cash equivalents | Level 1
Assets:
Assets measured at fair value	411,477	440,013
Cash equivalents | Level 2
Assets:
Assets measured at fair value	64,995	59,995
Short-term investments
Assets:
Assets measured at fair value	145,154	140,205
Short-term investments | Level 2
Assets:
Assets measured at fair value	145,154	140,205
Prepaid expenses and other
Assets:
Assets measured at fair value	654	1,561
Prepaid expenses and other | Level 2
Assets:
Assets measured at fair value	654	1,561
Long-term investments
Assets:
Assets measured at fair value	55,153	50,057
Long-term investments | Level 2
Assets:
Assets measured at fair value	55,153	50,057
Total assets measured at fair value
Liabilities:
Total liabilities measured at fair value	5,241	200
Total assets measured at fair value | Level 2
Liabilities:
Total liabilities measured at fair value	5,241	200
Other long-term obligations
Liabilities:
Other Liabilities, Fair Value Disclosure	4,648	2,083
Other long-term obligations | Level 2
Liabilities:
Other Liabilities, Fair Value Disclosure	$ 4,648	$ 2,083