Income Taxes (Taxability Of Common And Preferred Share Distributions) (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Series C Preferred Shares
Ordinary income (in hundredths)	100.00%	100.00%	100.00%
Return of Capital (in hundredths)	0.00%	0.00%	0.00%
Capital Gain Distribution (in hundredths)	0.00%	0.00%	0.00%
Series D Preferred Shares
Ordinary income (in hundredths)	100.00%	100.00%	100.00%
Return of Capital (in hundredths)	0.00%	0.00%	0.00%
Capital Gain Distribution (in hundredths)	0.00%	0.00%	0.00%
Series E Preferred Shares
Ordinary income (in hundredths)	100.00%	100.00%	100.00%
Return of Capital (in hundredths)	0.00%	0.00%	0.00%
Capital Gain Distribution (in hundredths)	0.00%	0.00%	0.00%
Class A Common Shares
Ordinary income (in hundredths)	33.03%	37.91%	70.95%
Return of Capital (in hundredths)	66.97%	62.09%	29.05%
Capital Gain Distribution (in hundredths)	0.00%	0.00%	0.00%