Summary of Significant Accounting Policies (Details 2)	12 Months Ended
	Dec. 31, 2011 Y
Class B
Deferred Sales Commissions
Amortization period of the cost incurred at the time of sale (in years)	5
Required holding period of shares (in years)	6
Class C
Deferred Sales Commissions
Amortization period of the cost incurred at the time of sale (in years)	12
Required holding period of shares (in years)	12
Asset allocation product
Deferred Sales Commissions
Maximum amortization period of the cost incurred at the time of acquisition (in months)	3
Required holding period of shares (in years)	3