Comparative Quarterly Financial Information (Unaudited) (Details) (USD $)
In Thousands, except Per 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
Quarterly Financial Data [Abstract]                      
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
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
Earnings per Share:                      
Basic $ 0.46 $ 0.44 $ 0.46 $ 0.41 $ 0.41 $ 0.58 $ 0.53 $ 0.31 $ 1.76 $ 1.82 $ 1.47
Diluted $ 0.45 $ 0.43 $ 0.44 $ 0.40 $ 0.40 $ 0.55 $ 0.50 $ 0.30 $ 1.72 $ 1.75 $ 1.40
Dividend income and net investment gains reclassifications         $ 2,700         $ (11,425) $ (5,701)