Related Party Transactions (Tables)
 12 Months Ended
Oct. 31, 2016
Related Party Transactions Disclosure Table [Abstract]  
Summary of related party revenue transactions
 (in thousands) 2016 2015 2014
 Investment advisory and administrative fees$ 809,102$ 865,792$ 900,478
 Distribution fees  71,784  73,468  77,697
 Service fees  107,684  116,448  125,713
 Shareholder service fees  2,433  2,641  2,315
 Other revenue  2,133  2,384  2,093
 Total$ 993,136$ 1,060,733$ 1,108,296
Summary of sales proceeds and net realized gains earned on investments in sponsored funds classified as available-for-sale, including sponsored funds accounted for under the equity method
 (in thousands) 2016 2015 2014
 Proceeds from sales $ 10,895$ 44,736$ 79,829
 Net realized gains (losses)  2,154  3,943  (81)