Related Party Transactions (Details) (USD $)	3 Months Ended		9 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2012	Jul. 31, 2011	Oct. 31, 2011
Sponsored Funds [Abstract]
Investment advisory and administrative fees	$ 183,469,000	$ 202,614,000	$ 555,622,000	$ 583,785,000
Distribution fees	19,982,000	23,883,000	60,757,000	71,808,000
Service fees	30,760,000	37,426,000	95,124,000	111,249,000
Shareholder services fees	616,000	463,000	1,843,000	1,648,000
Total	234,827,000	264,386,000	713,346,000	768,490,000
Investment adivisory fees waived by the Company	2,100,000	2,600,000	6,700,000	10,400,000
Proceeds from sales	16,390,000	10,003,000	56,396,000	39,452,000
Net realized (losses) gains	(189,000)	(147,000)	(65,000)	405,000
Related party expenses	5,300,000	4,500,000	14,000,000	11,200,000
Related party accounts receivable	81,600,000		81,600,000		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%