Earnings Per Share Calculation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Jan. 31, 2018	Jan. 31, 2017
Numerator
Net income (loss)	$ (473,363)	$ 3,861
Denominator
Basic weighted average shares outstanding	143,922	140,682
Add: Shares underlying outstanding stock options and restricted stock units and issuable under employee stock purchase plan	0	1,502
Dilutive weighted average shares outstanding (in shares)	143,922	142,184
EPS
Basic EPS (in dollars per share)	$ (3.29)	$ 0.03
Diluted EPS (in dollars per share)	$ (3.29)	$ 0.03