Convertible Notes Payable - Private Exchange Offer Transactions (Details) (USD $)	3 Months Ended		9 Months Ended			0 Months Ended	3 Months Ended		0 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013 4.0% Convertible Senior Notes due December 15, 2020 [Member]	Dec. 27, 2012 Convertible Notes Payable [Member] 4.0% Convertible Senior Notes due December 15, 2020 [Member] D	Jan. 31, 2013 Convertible Notes Payable [Member] 4.0% Convertible Senior Notes due December 15, 2020 [Member]	Jul. 31, 2013 Convertible Notes Payable [Member] 4.0% Convertible Senior Notes due December 15, 2020 [Member]	Dec. 27, 2012 4.0% Convertible Senior Notes due March 15, 2015 [Member] Convertible Notes Payable [Member]
Debt Instrument [Line Items]
Principal amount of new series of convertible notes						$ 187,500,000
Interest rate on convertible notes					4.00%	4.00%
Retired principal amount									187,500,000
Retirement of outstanding notes, carrying value									187,900,000
Convertible notes issuance costs									2,300,000
Convertible notes redemption feature									600,000
Convertible notes fair value						213,600,000
Loss on extinguishment of debt	0	0	28,630,000	0			28,630,000
Accretion rate of principal amount						1.85%
Number of shares converted for each $1000 principal amount (in shares)						49.0557
Principal amount used for conversion of notes						1,000
Initial conversion price per share equivalent						$ 20.385
Redemption option, closing price to conversion price, minimum percentage						130.00%
Minimum number of trading days in 30 consecutive trading days 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 days
Shares of common stock reserved for future issuance						9,197,944
Effective interest rate for fair value of debt component of notes						7.00%
Fair value of debt component of notes						170,400,000
Carrying amount of equity component of convertible notes						$ 43,100,000		$ 43,131,000
Minimum percentage of aggregate principal amount required to be held by trustee or holders to declare notes immediately payable						25.00%