Related Party Transactions (Details) (USD $)	3 Months Ended		9 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013	Jul. 31, 2012	Oct. 31, 2012
Sponsored Funds [Abstract]
Investment advisory and administrative fees	$ 214,894,000	$ 183,469,000	$ 608,876,000	$ 555,622,000
Distribution fees	20,350,000	19,982,000	60,268,000	60,757,000
Service fees	32,259,000	30,760,000	94,521,000	95,124,000
Shareholder services fees	752,000	616,000	1,840,000	1,843,000
Other revenue	442,000		845,000
Total	268,697,000	234,827,000	766,350,000	713,346,000
Investment advisory fees waived by the Company	2,500,000	2,100,000	6,900,000	6,700,000
Proceeds from sales	2,927,000	16,390,000	42,217,000	56,396,000
Net realized gains (losses)	180,000	(189,000)	5,431,000	(65,000)
Related party expenses	5,500,000	5,300,000	16,200,000	14,000,000
Related party accounts receivable	92,000,000		92,000,000		84,400,000
Employee Loan Program
Maximum loan amount available under the plan	$ 20,000,000		$ 20,000,000
Minimum fixed borrowing rate under the plan			0.90%
Maximum fixed borrowing rate under the plan			5.00%