Earnings (Loss) Per Share Calculation - Reconciliation of Numerator and Denominator of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Numerator
Net income (loss)	$ 253,434	$ (344,690)	$ 1,261,953
Less: Loss on fair value of debt conversion liability		(12,894)	0
Net income (loss) used to calculate Diluted EPS	$ 253,434	$ (357,584)	$ 1,278,721
Denominator
Basic weighted average shares outstanding (in shares)	155,720	143,738	141,997
Add: Shares underlying outstanding stock options, employee stock purchase plan and restricted stock units (in shares)	1,892	0	1,354
Diluted weighted average shares outstanding (in shares)	157,612	143,738	169,919
Earning Per Share [Abstract]
Basic EPS (in dollars per share)	$ 1.63	$ (2.40)	$ 8.89
Diluted EPS (in dollars per share)	$ 1.61	$ (2.49)	$ 7.53
3.75% Convertible Senior Notes due October 15, 2018 (New)
Denominator
Add: Shares underlying Convertible Senior Notes (in shares)	0	0	404
Earning Per Share [Abstract]
Interest rate on convertible notes	3.75%
0.875% Convertible Senior Notes due June 15, 2017
Numerator
Interest expense associated with Convertible Senior Notes due	$ 0	$ 0	$ 853
Denominator
Add: Shares underlying Convertible Senior Notes (in shares)	0	0	3,032
Earning Per Share [Abstract]
Interest rate on convertible notes	0.875%
3.75% Convertible Senior Notes due October 15, 2018 (Original)
Numerator
Interest expense associated with Convertible Senior Notes due	$ 0	$ 0	$ 7,224
Denominator
Add: Shares underlying Convertible Senior Notes (in shares)	0	0	13,934
Earning Per Share [Abstract]
Interest rate on convertible notes	3.75%	3.75%
4.0% Convertible Senior Notes due December 15, 2020
Numerator
Interest expense associated with Convertible Senior Notes due	$ 0	$ 0	$ 8,691
Denominator
Add: Shares underlying Convertible Senior Notes (in shares)	0	0	9,198
Earning Per Share [Abstract]
Interest rate on convertible notes	4.00%