Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Jan. 31, 2020	Oct. 31, 2019	Jan. 31, 2019	Oct. 31, 2018
Restricted Cash And Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 544,114	$ 557,668
Total cash, cash equivalents, and restricted cash presented in the Consolidated Statement of Cash Flows	620,887	653,345	$ 543,489	$ 866,075
Consolidated Sponsored Funds Included In Investments [Member]
Restricted Cash And Cash Equivalents Items [Line Items]
Restricted Cash	42,255	37,905
Assets Of Consolidated CLO Entities Cash [Member]
Restricted Cash And Cash Equivalents Items [Line Items]
Restricted Cash	21,439	48,704
Restricted Cash Included In Other Assets [Member]
Restricted Cash And Cash Equivalents Items [Line Items]
Restricted Cash	$ 13,079	$ 9,068