FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Thousands	Jan. 31, 2017	Oct. 31, 2016
Assets:
U.S. government obligations	$ 359,990
Fair value, Measurements, Recurring
Assets:
Money market funds	529,967	$ 625,277
U.S. government obligations	340,038	350,431
Commercial paper	39,925	69,959
Foreign currency forward contracts	361	175
Total assets measured at fair value	910,291	1,045,842
Liabilities:
Foreign currency forward contracts and forward starting interest rate swap	496	1,396
Forward starting interest rate swap	1,475	5,967
Total liabilities measured at fair value	1,971	7,363
Fair value, Measurements, Recurring | Level 1
Assets:
Money market funds	529,967	625,277
U.S. government obligations	0	0
Commercial paper	0	0
Foreign currency forward contracts	0	0
Total assets measured at fair value	529,967	625,277
Liabilities:
Foreign currency forward contracts and forward starting interest rate swap	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	340,038	350,431
Commercial paper	39,925	69,959
Foreign currency forward contracts	361	175
Total assets measured at fair value	380,324	420,565
Liabilities:
Foreign currency forward contracts and forward starting interest rate swap	496	1,396
Forward starting interest rate swap	1,475	5,967
Total liabilities measured at fair value	1,971	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 and forward starting interest rate swap	0	0
Forward starting interest rate swap	0	0
Total liabilities measured at fair value	$ 0	$ 0