Financial Highlights (Net Investment Income Ratio To Average Equity) (Details)		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Investment Company, Financial Highlights [Abstract]
Net Investment Income (Loss) Ratio	[1],[2]	7.75%	4.95%	7.20%	5.86%

[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.