EARNINGS PER SHARE CALCULATION (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2017	Jul. 31, 2016
Numerator
Net income	$ 60,010	$ 33,546	$ 101,897	$ 35,997
Net income used to calculate Diluted EPS	$ 67,151	$ 38,444	$ 113,990	$ 35,997
Denominator
Basic weighted average shares outstanding (in shares)	142,464	138,881	141,631	137,835
Add: Shares underlying outstanding stock options and restricted stock units and issuable under employee stock purchase plan (in shares)	1,386	895	1,401	1,218
Dilutive weighted average shares outstanding (in shares)	172,112	169,349	164,431	139,053
EPS
Basic EPS (in dollars per share)	$ 0.42	$ 0.24	$ 0.72	$ 0.26
Diluted EPS (in dollars per share)	$ 0.39	$ 0.23	$ 0.69	$ 0.26
0.875% Convertible Senior Notes due June 15, 2017
Numerator
Add: Interest expense associated with Convertible Senior Notes	$ 246	$ 1,326	$ 1,343	$ 0
Denominator
Add: Shares underlying Convertible Senior Notes (in shares)	1,708	12,217	4,043	0
3.75% Convertible Senior Notes due October 15, 2018
Numerator
Add: Interest expense associated with Convertible Senior Notes	$ 3,572	$ 3,572	$ 10,750	$ 0
Denominator
Add: Shares underlying Convertible Senior Notes (in shares)	17,356	17,356	17,356	0
4.0% Convertible Senior Notes due December 15, 2020
Numerator
Add: Interest expense associated with Convertible Senior Notes	$ 3,323	$ 0	$ 0	$ 0
Denominator
Add: Shares underlying Convertible Senior Notes (in shares)	9,198	0	0	0