Fees (Details) (Maximum [Member])	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2012
Monthly Payment [Member]
Other Noninterest Expense [Line Items]
Less incentive fee allocations	20.00%
Management fee as percentage of month-end net assets		0.167%
Annual Payment [Member]
Other Noninterest Expense [Line Items]
Management fee as percentage of month-end net assets		2.00%