Financial Highlights (Net Investment Income Ratio To Average Equity) (Details)		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Investment Company, Financial Highlights [Abstract]
Net Investment Income (Loss) Ratio	[1],[2]	7.34%	5.24%	7.01%	6.31%

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

[2] Includes all items of income and expense on an annualized basis except for incentive fee expense which is included on a non-annualized basis.