Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis Transfer Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2017	Apr. 30, 2016
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis Details [Abstract]
Transfers from Level 1 into Level 2	$ 48	$ 129	$ 457	$ 118
Transfers from Level 2 into Level 1	$ 42	$ 86	$ 47	$ 102

Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2 during the reporting periods.

No definition available.

Name:	ev_FairValueAssetsLevel1ToLevel2TransferAmounts
Namespace Prefix:	ev_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration