Acquisitions, Goodwill and Intangible Assets (Schedule of the Carrying Amounts of Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2019	Oct. 31, 2018
Amortizing intangible assets:
Accumulated amortization	$ (118,669)	$ (113,691)
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross intangible assets	194,576	194,576
Intangible assets, net	75,907	80,885
Mutual Fund Management Contract Acquired [Member]
Non-amortizing intangible assets:
Net carrying amount	54,408	54,408
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross intangible assets	54,408	54,408
Client Relationships Acquired [Member]
Amortizing intangible assets:
Gross carrying amount	134,247	134,247
Accumulated amortization	(115,921)	(111,591)
Net carrying amount	$ 18,326	$ 22,656
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Weighted-average remaining amortization period (in years)	9 years 6 months	9 years 6 months
Intellectual Property Acquired [Member]
Amortizing intangible assets:
Gross carrying amount	$ 1,025	$ 1,025
Accumulated amortization	(586)	(519)
Net carrying amount	$ 439	$ 506
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Weighted-average remaining amortization period (in years)	6 years 7 months 6 days	7 years 7 months 6 days
Trademark Acquired [Member]
Amortizing intangible assets:
Gross carrying amount	$ 4,257	$ 4,257
Accumulated amortization	(1,558)	(1,190)
Net carrying amount	$ 2,699	$ 3,067
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Weighted-average remaining amortization period (in years)	11 years 1 month 6 days	11 years 7 months 6 days
Research System Aquired [Member]
Amortizing intangible assets:
Gross carrying amount	$ 639	$ 639
Accumulated amortization	(604)	(391)
Net carrying amount	$ 35	$ 248
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Weighted-average remaining amortization period (in years)	2 months 12 days	1 year 2 months 12 days