New Accounting Standards Not Yet Adopted (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2016
Fund Related Expense	$ 64,538	$ 48,995	$ 35,899
Distribution and underwriter fees and distribution expense	141,418	132,873	$ 117,996
Accounting Standards Update 2014-09 [Member]
Fund Related Expense	26,900	13,900
Distribution and underwriter fees and distribution expense	17,100	$ 17,000
Accounting Standards Update 2016-01 [Member]
Equity securities	10,300
Net unrealized holding gains, net of tax, attributable to securities from AOCI to retained earnings, reclassification	$ 3,700