FAIR VALUE MEASUREMENTS (Details 2) - Fair value, Measurements, Recurring - USD ($) $ in Thousands	Apr. 30, 2017	Oct. 31, 2016
Assets:
Total assets measured at fair value	$ 899,881	$ 1,045,842
Liabilities:
Total liabilities measured at fair value	2,881	7,363
Cash equivalents
Assets:
Total assets measured at fair value	534,423	680,247
Short-term investments
Assets:
Total assets measured at fair value	274,779	275,248
Prepaid expenses and other
Assets:
Total assets measured at fair value	827	175
Long-term investments
Assets:
Total assets measured at fair value	89,852	90,172
Accrued liabilities
Liabilities:
Total liabilities measured at fair value	1,811	1,396
Other long-term obligations
Liabilities:
Total liabilities measured at fair value	1,070	5,967
Level 1
Assets:
Total assets measured at fair value	474,476	625,277
Liabilities:
Total liabilities measured at fair value	0	0
Level 1 | Cash equivalents
Assets:
Total assets measured at fair value	474,476	625,277
Level 1 | Short-term investments
Assets:
Total assets measured at fair value	0	0
Level 1 | Prepaid expenses and other
Assets:
Total assets measured at fair value	0	0
Level 1 | Long-term investments
Assets:
Total assets measured at fair value	0	0
Level 1 | Accrued liabilities
Liabilities:
Total liabilities measured at fair value	0	0
Level 1 | Other long-term obligations
Liabilities:
Total liabilities measured at fair value	0	0
Level 2
Assets:
Total assets measured at fair value	425,405	420,565
Liabilities:
Total liabilities measured at fair value	2,881	7,363
Level 2 | Cash equivalents
Assets:
Total assets measured at fair value	59,947	54,970
Level 2 | Short-term investments
Assets:
Total assets measured at fair value	274,779	275,248
Level 2 | Prepaid expenses and other
Assets:
Total assets measured at fair value	827	175
Level 2 | Long-term investments
Assets:
Total assets measured at fair value	89,852	90,172
Level 2 | Accrued liabilities
Liabilities:
Total liabilities measured at fair value	1,811	1,396
Level 2 | Other long-term obligations
Liabilities:
Total liabilities measured at fair value	1,070	5,967
Level 3
Assets:
Total assets measured at fair value	0	0
Liabilities:
Total liabilities measured at fair value	0	0
Level 3 | Cash equivalents
Assets:
Total assets measured at fair value	0	0
Level 3 | Short-term investments
Assets:
Total assets measured at fair value	0	0
Level 3 | Prepaid expenses and other
Assets:
Total assets measured at fair value	0	0
Level 3 | Long-term investments
Assets:
Total assets measured at fair value	0	0
Level 3 | Accrued liabilities
Liabilities:
Total liabilities measured at fair value	0	0
Level 3 | Other long-term obligations
Liabilities:
Total liabilities measured at fair value	$ 0	$ 0