Short-Term and Long-Term Debt - Outstanding Convertible Notes Payable Net Carry Value and Estimated Fair Value (Details) - USD ($) $ in Thousands	Apr. 30, 2018	Oct. 31, 2017
Convertible notes payable
Debt Instrument [Line Items]
Net Carrying Value	$ 547,180	$ 543,009
Fair Value	$ 727,300
3.75% Convertible Senior Notes due October 15, 2018 (Original)
Debt Instrument [Line Items]
Interest rate on convertible notes (as a percent)	3.75%
3.75% Convertible Senior Notes due October 15, 2018 (Original) \| Convertible notes payable
Debt Instrument [Line Items]
Net Carrying Value	$ 61,180	61,071
Fair Value	$ 80,907
3.75% Convertible Senior Notes due October 15, 2018 (New)
Debt Instrument [Line Items]
Interest rate on convertible notes (as a percent)	3.75%
3.75% Convertible Senior Notes due October 15, 2018 (New) \| Convertible notes payable
Debt Instrument [Line Items]
Net Carrying Value	$ 288,028	287,221
Fair Value	$ 381,268
4.0% Convertible Senior Notes due December 15, 2020
Debt Instrument [Line Items]
Interest rate on convertible notes (as a percent)	4.00%
4.0% Convertible Senior Notes due December 15, 2020 \| Convertible notes payable
Debt Instrument [Line Items]
Net Carrying Value	$ 197,972	$ 194,717
Fair Value	$ 265,125

Fair value portion of borrowing which can be exchanged for a specified number of another security at the option of the issuer or the holder, for example, but not limited to, the entity's common stock.

No definition available.

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- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of a written promise to pay a note, initially due after one year or beyond the operating cycle if longer, which can be exchanged for a specified amount of one or more securities (typically common stock), at the option of the issuer or the holder.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-04(13))
-URI http://asc.fasb.org/extlink&oid=6488278&loc=d3e603758-122996

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Details

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