Basis of Presentation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2011	Jan. 31, 2011	Oct. 31, 2012	Oct. 31, 2011	Oct. 31, 2010
Schedule Of Basis Of Presentation [Line Items]
Other revenue									$ 5,223	$ 4,875	$ 4,541
Total revenue	309,889	298,771	304,770	295,606	297,323	327,056	315,613	308,614	1,209,036	1,248,606	1,115,960
Operating income	106,345	95,016	98,811	92,820	104,648	115,427	106,812	99,345	392,992	426,232	347,581
Gains and other investment income, net									18,417	19,408	13,046
Net income									264,768	227,574	201,225
Net income attributable to Eaton Vance Corp. shareholders	53,118	50,206	52,870	47,271	46,820	68,068	62,479	37,535	203,465	214,902	174,298
Dividend income and net investment gains reclassifications					2,700					(11,425)	(5,701)
As Previously Reported [Member]
Schedule Of Basis Of Presentation [Line Items]
Other revenue										16,300	10,242
Total revenue										1,260,031	1,121,661
Operating income										437,657	353,282
Gains and other investment income, net										7,983	7,345
Net income										227,574	201,225
Net income attributable to Eaton Vance Corp. shareholders										214,902	174,298
As Reclassified [Member]
Schedule Of Basis Of Presentation [Line Items]
Other revenue										4,875	4,541
Total revenue										1,248,606	1,115,960
Operating income										426,232	347,581
Gains and other investment income, net										19,408	13,046
Net income										227,574	201,225
Net income attributable to Eaton Vance Corp. shareholders										$ 214,902	$ 174,298