Financial Highlights (Expense Ratios To Average Equity) (Details)	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Financial Highlights [Abstract]
Operating expenses before incentive fee, interest expense, and other investment related expenses	(2.76%)	[1],[2]	(2.81%)	[1],[2]	(2.78%)	[1],[2]	(2.79%)	[1],[2]
Ratio Of Incentive Fee To Average Equity	0.00%	[1],[2]	(0.20%)	[1],[2]	0.00%	[1],[2]	(0.58%)	[1],[2]
Interest expense and other investment related expenses	(2.32%)	[1],[2]	(2.01%)	[1],[2]	(2.15%)	[1],[2]	(1.83%)	[1],[2]
Total Expenses	(5.08%)	[1],[2]	(5.02%)	[1],[2]	(4.93%)	[1],[2]	(5.20%)	[1],[2]

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

[2] Ratios are annualized except for the incentive fee which is not annualized.