FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Thousands	Apr. 30, 2017	Oct. 31, 2016
Assets:
U.S. government obligations	$ 364,631
Fair value, Measurements, Recurring
Assets:
Money market funds	474,476	$ 625,277
U.S. government obligations	344,661	350,431
Commercial paper	79,917	69,959
Foreign currency forward contracts	827	175
Total assets measured at fair value	899,881	1,045,842
Liabilities:
Foreign currency forward contracts	1,811	1,396
Forward starting interest rate swap	1,070	5,967
Total liabilities measured at fair value	2,881	7,363
Fair value, Measurements, Recurring | Level 1
Assets:
Money market funds	474,476	625,277
U.S. government obligations	0	0
Commercial paper	0	0
Foreign currency forward contracts	0	0
Total assets measured at fair value	474,476	625,277
Liabilities:
Foreign currency forward contracts	0	0
Forward starting interest rate swap	0	0
Total liabilities measured at fair value	0	0
Fair value, Measurements, Recurring | Level 2
Assets:
Money market funds	0	0
U.S. government obligations	344,661	350,431
Commercial paper	79,917	69,959
Foreign currency forward contracts	827	175
Total assets measured at fair value	425,405	420,565
Liabilities:
Foreign currency forward contracts	1,811	1,396
Forward starting interest rate swap	1,070	5,967
Total liabilities measured at fair value	2,881	7,363
Fair value, Measurements, Recurring | Level 3
Assets:
Money market funds	0	0
U.S. government obligations	0	0
Commercial paper	0	0
Foreign currency forward contracts	0	0
Total assets measured at fair value	0	0
Liabilities:
Foreign currency forward contracts	0	0
Forward starting interest rate swap	0	0
Total liabilities measured at fair value	$ 0	$ 0