Acquisitions (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Jan. 31, 2020
Parametric Portfolio Associates [Member]
Business Acquisition [Line Items]
Total Non-controlling profits interests (direct and indirect) held by interest holders at the end of period	0.00%		0.00%
Total capital interest held by non-controlling interest holders	0.00%		0.00%
Atlanta Capital [Member]
Business Acquisition [Line Items]
Total Non-controlling profits interests (direct and indirect) held by interest holders at the end of period	8.20%		8.20%
Amount paid for indirect profit interest pursuant to the put and call provisions of the Long-term Equity Incentive Plan	$ 7.8	$ 8.2
Estimated fair value of noncontrolling interests	25.2		$ 25.5
Parametric Portfolio Associates [Member] | Parametric Plan [Member]
Business Acquisition [Line Items]
Amount paid for indirect profit interest pursuant to the put and call provisions of the Long-term Equity Incentive Plan	$ 0.6	$ 5.9