Financial Highlights (Expense Ratios To Average Equity) (Details)	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Financial Highlights [Abstract]
Operating expenses before incentive fee and interest expense	(2.81%)	[1]	(3.09%)	[1]
Ratio Of Incentive Fee To Average Equity	(0.39%)	[1]	0.00%	[1]
Interest expense	(1.66%)	[1]	(1.92%)	[1]
Total Expenses	(4.86%)	[1]	(5.01%)	[1]

[1] Average equity is calculated using month end values.