Debt Instrument, Convertible, Threshold Cash Settlement

No definition available.

Name:	cien_DebtInstrumentConvertibleThresholdCashSettlement
Namespace Prefix:	cien_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Repayments of Convertible Debt, Embedded Derivative

+ References

No definition available.

+ Details

Name:	cien_RepaymentsofConvertibleDebtEmbeddedDerivative
Namespace Prefix:	cien_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Stock Issued During Period, Shares, Conversion of Convertible Securities, Embedded Derivative

+ References

No definition available.

+ Details

Name:	cien_StockIssuedDuringPeriodSharesConversionofConvertibleSecuritiesEmbeddedDerivative
Namespace Prefix:	cien_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Nominal or face amount used to calculate payments on the derivative asset.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeAssetNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- 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.

+ Details

Name:	us-gaap_DerivativeInstrumentsGainLossLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Fixed interest rate that will be received or paid upon exercise of the interest rate swaption contract.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeSwaptionInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Period the derivative contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value as of the balance sheet date of the embedded derivative or group of embedded derivatives classified as a liability.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624163-113959

+ Details

Name:	us-gaap_EmbeddedDerivativeFairValueOfEmbeddedDerivativeLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Net Increase or Decrease in the fair value of the embedded derivative or group of embedded derivatives included in earnings in the period.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 15
-URI http://asc.fasb.org/subtopic&trid=2229187

+ Details

Name:	us-gaap_EmbeddedDerivativeGainLossOnEmbeddedDerivativeNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount, after tax and reclassification, of gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness, attributable to parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e637-108580

+ Details

Name:	us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage of an entity's outstanding debt that is designated as a hedged item in cash flow, fair value, or net investment hedge.

+ References

No definition available.

+ Details

Name:	us-gaap_PercentageOfDebtHedgedByInterestRateDerivatives
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_DebtInstrumentAxis=cien_TermLoan2022Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cien_TermLoan2025Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cien_NewNotesThreePointSevenFivePercentConvertibleSeniorNotesDue2018Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_ConvertibleNotesPayableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeForwardMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_CashFlowHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Derivative Instruments (Details) - USD ($) shares in Millions		3 Months Ended	12 Months Ended
	Nov. 15, 2018	Oct. 31, 2018	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2016	Oct. 15, 2018	Sep. 28, 2018	Aug. 30, 2018	Aug. 02, 2017	Jan. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Embedded conversion feature		$ 164,212,000	$ 164,212,000	$ 0				$ 152,100,000
Loss on fair value of debt conversion liability			12,070,000	0	$ 0
Term Loan Payable due January 30, 2022 \| Secured Debt
Derivative Instruments, Gain (Loss) [Line Items]
Term loan principal amount		$ 700,000,000	$ 700,000,000							$ 400,000,000
Term Loan Payable due September 28, 2025 \| Secured Debt
Derivative Instruments, Gain (Loss) [Line Items]
Term loan principal amount							$ 700,000,000
3.75% Convertible Senior Notes due October 15, 2018 (New)
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate on convertible notes		3.75%	3.75%
3.75% Convertible Senior Notes due October 15, 2018 (New) \| Convertible Notes Payable
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate on convertible notes									3.75%
Maximum cash settlement of convertible debt						$ 400,000,000		$ 400,000,000
Embedded conversion feature		$ 152,100,000	$ 152,100,000
Maximum
Derivative Instruments, Gain (Loss) [Line Items]
Foreign exchange contract maturities			24 months
Foreign Exchange Forward
Derivative Instruments, Gain (Loss) [Line Items]
Gain on unwounding of interest rate swaps			$ (1,674,000)	(295,000)	(823,000)
Interest Rate Swap
Derivative Instruments, Gain (Loss) [Line Items]
Gain on unwounding of interest rate swaps			6,199,000	6,185,000	$ (445,000)
Designated as Hedging Instrument \| Foreign Exchange Forward \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Notional principal of contract		163,200,000	$ 163,200,000	86,100,000
Designated as Hedging Instrument \| Foreign Exchange Forward \| Cash Flow Hedging \| Maximum
Derivative Instruments, Gain (Loss) [Line Items]
Foreign exchange contract maturities			24 months
Designated as Hedging Instrument \| Interest Rate Swap \| Cash Flow Hedging \| Term Loan Payable due January 30, 2022 \| Secured Debt
Derivative Instruments, Gain (Loss) [Line Items]
Gain on unwounding of interest rate swaps		6,800,000
Designated as Hedging Instrument \| Interest Rate Swap \| Cash Flow Hedging \| Term Loan Payable due September 28, 2025 \| Secured Debt
Derivative Instruments, Gain (Loss) [Line Items]
Notional principal of contract		$ 350,000,000	$ 350,000,000
Interest rate swap fix		50.00%	50.00%
Fixed interest amount resulting from interest rate swap		2.957%	2.957%
Not Designated as Hedging Instrument \| Foreign Exchange Forward
Derivative Instruments, Gain (Loss) [Line Items]
Notional principal of contract		$ 162,600,000	$ 162,600,000	$ 83,400,000
Not Designated as Hedging Instrument \| Foreign Exchange Forward \| Maximum
Derivative Instruments, Gain (Loss) [Line Items]
Foreign exchange contract maturities			12 months
Subsequent Event \| 3.75% Convertible Senior Notes due October 15, 2018 (New) \| Convertible Notes Payable
Derivative Instruments, Gain (Loss) [Line Items]
Cash paid for embedded conversion feature	$ 111,300,000
Shares issued for embedded conversion feature (in shares)	1.6