Net Income Per Share (Schedule Of Calculation Of Basic And Diluted Net Income (Loss) Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Jul. 29, 2017	Jul. 30, 2016	Jul. 29, 2017	Jul. 30, 2016	Jan. 31, 2015
Earnings Per Share, Basic
Net income (loss) attributable to Brocade Communications Systems, Inc.		$ (19,506)	$ 10,495	$ (36,154)	$ 147,226
Weighted-average shares used in computing basic net income (loss) per share		411,898	426,671	408,494	411,709
Net income (loss) per share—basic attributable to Brocade Communications Systems, Inc. stockholders		$ (0.05)	$ 0.02	$ (0.09)	$ 0.36
Earnings Per Share, Diluted
Net income (loss) attributable to Brocade Communications Systems, Inc.		$ (19,506)	$ 10,495	$ (36,154)	$ 147,226
Weighted-average shares used in computing diluted net income (loss) per share		411,898	434,416	408,494	419,416
Net income (loss) per share—diluted attributable to Brocade Communications Systems, Inc. stockholders		$ (0.05)	$ 0.02	$ (0.09)	$ 0.35
Weighted Average Number of Shares Outstanding Reconciliation
Weighted-average shares used in computing basic net income (loss) per share		411,898	426,671	408,494	411,709
Dilutive potential common shares in the form of stock options		0	1,227	0	1,329
Dilutive potential common shares in the form of other share-based awards		0	6,518	0	6,378
Weighted-average shares used in computing diluted net income (loss) per share		411,898	434,416	408,494	419,416
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive potential common shares	[1]	1,334	2,838	1,605	2,029
Other share-based awards
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive potential common shares	[1]	8,183	2,120	8,888	1,140
Convertible Senior Unsecured 2020 Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share
Debt Instrument, Convertible, Conversion Price		$ 15.72		$ 15.72		$ 15.93
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 20.38		$ 20.38		$ 20.65
Convertible Senior Unsecured 2020 Notes | Warrant
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive potential common shares	[1],[2]	36,573	36,316	36,515	36,251

[1] These amounts are excluded from the computation of diluted net income (loss) per share.

[2] In connection with the issuance of the 2020 Convertible Notes, the Company entered into convertible note hedge and warrant transactions as described in Note 8, “Borrowings.” The 2020 Convertible Notes have no impact on diluted earnings per share until the average quarterly price of the Company’s common stock exceeds the adjusted conversion price of $15.72 per share. If the common stock price exceeds this adjusted conversion price, then immediately, prior to conversion, the Company will calculate the effect of the additional shares that may be issued using the treasury stock method. If the average price of the Company’s common stock exceeds $20.38 per share for a quarterly period, the Company’s weighted-average shares used in computing diluted net income per share will be impacted by the effect of the additional potential shares that may be issued related to the warrants using the treasury stock method. The convertible note hedge is not considered for purposes of the diluted earnings per share calculation, as its effect would be antidilutive.