Financial Highlights (Expense Ratios To Average Equity) (Details)		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financial Highlights [Abstract]
Operating expenses, before interest expense and other investment related expenses	[1]	(2.69%)	(2.80%)	(2.74%)
Incentive fee	[1]	0.00%	(0.21%)	(1.42%)
Interest expense and other investment related expenses	[1]	(2.30%)	(2.14%)	(1.95%)
Total Expenses	[1]	(4.99%)	(5.15%)	(6.11%)

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