Earnings Per Share (Details) (USD $) In Thousands, except Share data, 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
Earnings Per Share Reconciliation [Abstract]
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
Less: Allocation of earnings to participating restricted shares									5,676	4,597	2,675
Net income available to common shareholders (basic)									$ 197,789	$ 210,305	$ 171,623
Weighted-average shares outstanding - basic									112,359,000	115,326,000	116,444,000
Incremental common shares									2,767,000	4,649,000	6,188,000
Weighted-average shares outstanding - diluted									115,126,000	119,975,000	122,632,000
Earnings per share (Basic) ($ per share)	$ 0.46	$ 0.44	$ 0.46	$ 0.41	$ 0.41	$ 0.58	$ 0.53	$ 0.31	$ 1.76	$ 1.82	$ 1.47
Earnings per share (Diluted) ($ per share)	$ 0.45	$ 0.43	$ 0.44	$ 0.40	$ 0.40	$ 0.55	$ 0.50	$ 0.30	$ 1.72	$ 1.75	$ 1.40
Antidilutive common shares									14,900,000	12,100,000	9,000,000