Financial Highlights (Net Investment Income Ratio To Average Equity) (Details)		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financial Highlights [Abstract]
Net Investment Income	[1],[2]	8.59%	8.62%	8.40%

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

[2] Includes incentive fee in calculation which can vary substantially over periods.