Basis of Presentation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Apr. 30, 2012	Apr. 30, 2011	Apr. 30, 2012	Apr. 30, 2011
Schedule Of Basis Of Presentation [Line Items]
Other revenue	$ 1,266	$ 1,324	$ 2,606	$ 2,532
Total revenue	304,770	315,613	600,376	624,227
Operating income	98,811	106,812	191,631	206,157
Gains and other investment income, net	2,796	12,492	10,973	13,812
Net income	62,770	53,765	127,640	113,050
Net income attributable to Eaton Vance Corp. shareholders	52,870	62,479	100,141	100,014
Dividend income and net investment gains reclassifications		(10,225)		(13,898)
As Previously Reported [Member]
Schedule Of Basis Of Presentation [Line Items]
Other revenue		11,549		16,430
Total revenue		325,838		638,125
Operating income		117,037		220,055
Gains and other investment income, net		2,267		(86)
Net income		53,765		113,050
Net income attributable to Eaton Vance Corp. shareholders		62,479		100,014
As Reclassified [Member]
Schedule Of Basis Of Presentation [Line Items]
Other revenue		1,324		2,532
Total revenue		315,613		624,227
Operating income		106,812		206,157
Gains and other investment income, net		12,492		13,812
Net income		53,765		113,050
Net income attributable to Eaton Vance Corp. shareholders		$ 62,479		$ 100,014