Financial Highlights (Net Investment Income Ratio To Average Shareholders Equity) (Details)	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Financial Highlights [Abstract]
Net Investment Income	7.04%	[1],[2]	11.46%	[1],[2]	7.65%	[1],[2]	11.59%	[1],[2]

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

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