Acquisitions, Goodwill and Intangible Assets (Schedule of the carrying amounts of intangible assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2020	Oct. 31, 2019
Total intangible assets:
Gross carrying amount	$ 242,651	$ 194,576
Accumulated amortization	(122,476)	(118,669)
Net carrying amount	120,175	75,907
Mutual Fund Management Contracts Acquired [Member]
Total intangible assets:
Gross carrying amount	54,408	54,408
Non-amortizing intangible assets:
Net carrying amount	54,408	54,408
Client Relationships Acquired [Member]
Total intangible assets:
Gross carrying amount	180,772	134,247
Accumulated amortization	(119,365)	(115,921)
Net carrying amount	$ 61,407	$ 18,326
Non-amortizing intangible assets:
Weighted-average remaining amortization period (in years)	13 years 8 months 12 days	9 years 6 months
Client Relationships Acquired [Member] | Wateroak Advisors, LLC [Member]
Non-amortizing intangible assets:
Weighted-average remaining amortization period (in years)	15 years
Intellectual Property Acquired [Member]
Total intangible assets:
Gross carrying amount	$ 1,025	$ 1,025
Accumulated amortization	(653)	(586)
Net carrying amount	$ 372	$ 439
Non-amortizing intangible assets:
Weighted-average remaining amortization period (in years)	5 years 7 months 6 days	6 years 7 months 6 days
Trademark Acquired [Member]
Total intangible assets:
Gross carrying amount	$ 4,782	$ 4,257
Accumulated amortization	(1,819)	(1,558)
Net carrying amount	$ 2,963	$ 2,699
Non-amortizing intangible assets:
Weighted-average remaining amortization period (in years)	10 years 1 month 6 days	11 years 1 month 6 days
Trademark Acquired [Member] | Wateroak Advisors, LLC [Member]
Non-amortizing intangible assets:
Weighted-average remaining amortization period (in years)	10 years
Assembled Workforce Acquired [Member]
Total intangible assets:
Gross carrying amount	$ 1,025
Accumulated amortization	0
Net carrying amount	$ 1,025
Non-amortizing intangible assets:
Weighted-average remaining amortization period (in years)	15 years
Assembled Workforce Acquired [Member] | Wateroak Advisors, LLC [Member]
Non-amortizing intangible assets:
Weighted-average remaining amortization period (in years)	15 years
Research System Acquired [Member]
Total intangible assets:
Gross carrying amount	$ 639	$ 639
Accumulated amortization	(639)	(604)
Net carrying amount	$ 0	$ 35
Non-amortizing intangible assets:
Weighted-average remaining amortization period (in years)		2 months 12 days