Related Party Transactions (Details) (USD $)	3 Months Ended		6 Months Ended
	Apr. 30, 2012	Apr. 30, 2011	Apr. 30, 2012	Apr. 30, 2011	Oct. 31, 2011
Sponsored Funds [Abstract]
Investment advisory and administrative fees	$ 188,669,000	$ 194,214,000	$ 372,153,000	$ 381,171,000
Distribution fees	20,298,000	23,502,000	40,775,000	47,925,000
Service fees	32,065,000	36,478,000	64,364,000	73,823,000
Shareholder services fees	630,000	667,000	1,227,000	1,185,000
Total	241,662,000	254,861,000	478,519,000	504,104,000
Investment adivisory fees waived by the Company	2,100,000	3,300,000	4,500,000	7,800,000
Proceeds from sales	32,804,000	1,178,000	40,006,000	29,449,000
Net realized gains	61,000	85,000	124,000	552,000
Related party expenses	4,300,000	3,400,000	8,700,000	6,600,000
Related party accounts receivable	83,900,000		83,900,000		82,500,000
Maximum loan amount available under the plan	$ 10,000,000		$ 10,000,000
Minimum fixed borrowing rate under the plan			1.20%
Maximum fixed borrowing rate under the plan			5.00%