Acquisitions, Goodwill and Intangible Assets 1 (Details) (USD $)	12 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2015
Business Acquisition Contingent Consideration [Line Items]
Goodwill acquired	$ 0	$ 74,240,000
Clifton Group [Member]
Business Acquisition Purchase Price Allocation [Line Items]
Business acquisition cost of acquired entity cash paid		72,300,000
Fair market value of indirect ownership interest in Parametric issued		12,800,000
Finite intangible assets acquired through an acquisition		24,500,000
Business acquisition purchase price allocation goodwill amount		60,100,000
Business acquisition revenues		22,300,000
Business acquisition earnings		6,800,000
Parametric Portfolio Associates [Member]
Business Acquisition Contingent Consideration [Line Items]
Non-controlling interest holders capital ownership percentage, end of period	2.70%	1.90%
Non-controlling interest holders total (direct and indirect) profits interest, end of period	7.90%	6.70%
Profits interest granted to non-controlling interest holders (employees)	0.40%
Parametric Portfolio Associates [Member] | Put Option [Member]
Business Acquisition Contingent Consideration [Line Items]
Minority interest ownership percentage purchased by parent		3.40%
Company's increase in profit interest percentage, during the period		5.70%
Capital interest granted to non-controlling interest holders (employees)	0.50%
Purchase of non-controlling interests		43,500,000
Amount paid for exercise of put right related to indrect profit units	5,400,000
Tax Advantaged Bond Strategies [Member]
Business Acquisition Contingent Consideration [Line Items]
Contingent payment made during the period		14,100,000
Goodwill acquired		14,100,000
Parametric Risk Advisors [Member]
Business Acquisition Contingent Consideration [Line Items]
Minority interest ownership percentage purchased by parent	20.00%
Company's capital ownership interest, beginning of period		70.00%
Company's capital ownership interest at the end of the period		80.00%
Noncontrolling indirect capital and profit interest acquired during the exchange by Parametric and issued to employees	0.80%
Parametric Risk Advisors [Member] | Call Option [Member]
Business Acquisition Contingent Consideration [Line Items]
Minority interest ownership percentage purchased by parent		10.00%
Purchase of non-controlling interests		3,100,000
Atlanta Capital [Member]
Business Acquisition Contingent Consideration [Line Items]
Non-controlling interest holders capital ownership percentage, end of period	0.10%	0.60%
Non-controlling interest holders total (direct and indirect) profits interest, end of period	13.80%	19.70%
Profits interest granted to non-controlling interest holders (employees)	1.20%
Non-controlling interest holders capital interest percentage that may be sold to the Company	0.30%
Non-controlling interest holders right to profits, expressed as a percentage	3.10%
Additional interest that may be purchased by the Company in future periods			100.00%	66.70%	66.70%
Atlanta Capital [Member] | Call Option [Member]
Business Acquisition Contingent Consideration [Line Items]
Minority interest ownership percentage purchased by parent		0.20%
Company's increase in profit interest percentage, during the period		3.40%
Purchase of non-controlling interests		12,800,000
Atlanta Capital [Member] | Put Option [Member]
Business Acquisition Contingent Consideration [Line Items]
Minority interest ownership percentage purchased by parent	0.10%	0.30%
Company's increase in profit interest percentage, during the period	1.30%	3.80%
Company's indirect profit units percentage purchased from an employee	0.30%
Purchase of non-controlling interests	6,600,000	14,100,000
Amount paid for exercise of put right related to indrect profit units	$ 300,000
Clifton Group [Member]
Business Acquisition Contingent Consideration [Line Items]
Noncontrolling indirect capital and profit interest acquired during the exchange by Parametric and issued to employees		1.90%