Comparative Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Comparative Quarterly Financial Information [Abstract]
Revenue	$ 433,740	$ 431,235	$ 411,861	$ 406,416	$ 430,795	$ 428,691	$ 412,700	$ 420,236	$ 1,683,252	$ 1,692,422	$ 1,532,111
Operating income	135,433	137,135	127,173	121,130	144,452	142,264	132,686	135,800	520,871	555,202	482,758
Net income	118,950	108,536	113,130	92,260	105,213	107,775	96,406	88,511	432,876	397,905	306,373
Net income attributable to Eaton Vance Corp. shareholders	$ 109,206	$ 102,221	$ 101,807	$ 86,801	$ 105,487	$ 101,794	$ 96,601	$ 78,056	$ 400,035	$ 381,938	$ 282,131
Earnings per share (Basic) ($ per share)	$ 1.00	$ 0.94	$ 0.92	$ 0.77	$ 0.93	$ 0.89	$ 0.84	$ 0.68	$ 3.63	$ 3.33	$ 2.54
Earnings per share (Diluted) ($ per share)	$ 0.96	$ 0.90	$ 0.89	$ 0.75	$ 0.87	$ 0.83	$ 0.78	$ 0.63	$ 3.50	$ 3.11	$ 2.42