Convertible Notes Payable (Details) (USD $)	12 Months Ended				3 Months Ended		12 Months Ended				3 Months Ended	12 Months Ended						3 Months Ended	12 Months Ended				3 Months Ended	12 Months Ended
	Oct. 31, 2012 D debtinstrument	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2012 Embedded redemption feature [Member]	Oct. 31, 2010 0.25% Convertible Senior Notes due May 1, 2013 [Member]	Apr. 30, 2006 0.25% Convertible Senior Notes due May 1, 2013 [Member]	Oct. 31, 2012 0.25% Convertible Senior Notes due May 1, 2013 [Member]	Aug. 13, 2012 0.25% Convertible Senior Notes due May 1, 2013 [Member]	Oct. 31, 2011 0.25% Convertible Senior Notes due May 1, 2013 [Member]	Apr. 10, 2006 0.25% Convertible Senior Notes due May 1, 2013 [Member]	Apr. 30, 2010 4.0% Convertible Senior Notes due March 15, 2015 [Member]	Oct. 31, 2012 4.0% Convertible Senior Notes due March 15, 2015 [Member]		Aug. 13, 2012 4.0% Convertible Senior Notes due March 15, 2015 [Member]	Oct. 31, 2011 4.0% Convertible Senior Notes due March 15, 2015 [Member]	Oct. 31, 2010 4.0% Convertible Senior Notes due March 15, 2015 [Member]	Mar. 15, 2010 4.0% Convertible Senior Notes due March 15, 2015 [Member]	Jul. 31, 2007 0.875% Convertible Senior Notes due June 15, 2017 [Member]	Oct. 31, 2012 0.875% Convertible Senior Notes due June 15, 2017 [Member]	Oct. 31, 2011 0.875% Convertible Senior Notes due June 15, 2017 [Member]	Oct. 31, 2010 0.875% Convertible Senior Notes due June 15, 2017 [Member]	Jun. 11, 2007 0.875% Convertible Senior Notes due June 15, 2017 [Member]	Oct. 31, 2010 3.75% Convertible Senior Notes due October 15, 2018 [Member]	Oct. 31, 2012 3.75% Convertible Senior Notes due October 15, 2018 [Member]	Oct. 31, 2011 3.75% Convertible Senior Notes due October 15, 2018 [Member]	Oct. 18, 2010 3.75% Convertible Senior Notes due October 15, 2018 [Member]
Convertible Notes Payable (Textuals) [Abstract]
Number of issuances of convertible notes payable outstanding	4
Minimum percentage of aggregate principal amount required to be held by trustee or holders to declare notes immediately payable	25.00%
Interest rate on convertible notes					0.25%		0.25%	0.25%	0.25%			4.00%		4.00%	4.00%	4.00%			0.875%	0.875%	0.875%		3.75%	3.75%	3.75%
Aggregate principal amount										$ 300,000,000							$ 375,000,000					$ 500,000,000				$ 350,000,000
Amount repurchased					81,800,000
Gain on extinguishment of debt	0	0	4,948,000		4,900,000
Convertible notes payable	216,210,000	0					216,210,000
Number of shares converted for each $1000 principal amount (in shares)							25.3001					49.0557							26.2154					49.5872
Principal amount used for conversion of notes	1,000
Initial conversion price per share equivalent (per share)							$ 39.5255					$ 20.38							$ 38.15					$ 20.17
Minimum number of trading days in 30 consecutive trading day period prior to redemption notice date where closing price exceeds conversion price by a minimum percentage	20
Number of consecutive trading day period prior to redemption notice date where closing price exceeds conversion price by a minimum percentage	30
Redemption option, closing price to conversion price, minimum percentage							130.00%					150.00%
Net proceeds from convertible senior notes offering used to purchase call spread option on its common stock						28,500,000												42,500,000
Discount rate used for make whole premium payment calculation												2.75%
Fair value of embedded redemption feature included in long-term assets	420,000	7,020,000		400,000
Change in fair value of embedded redemption feature included in interest and other income (loss)	(6,600,000)	2,800,000	2,510,000
Net proceeds from issuance of senior convertible notes	0	0	725,000,000								364,300,000												340,400,000
Net proceeds from convertible senior notes offering used to replace contractual obligation to issue convertible notes as part of acqusition											243,800,000
Net proceeds from convertible senior notes offering used to repurchase 0.25% convertible senior notes due 2013																							76,100,000
Carrying value and estimated current fair value of outstanding convertible notes
Long term convertible notes payable	1,225,806,000	1,442,364,000										375,806,000	[1]						500,000,000					350,000,000
Carrying Value	1,442,016,000
Fair Value	$ 1,396,810,000						$ 213,237,000					$ 397,885,000	[1]						$ 425,625,000					$ 360,063,000

[1] Includes unamortized bond premium related to embedded redemption feature