Income Taxes (Taxability Of Common And Preferred Share Distributions) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Series B Preferred Stock [Member]
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 C Preferred Shares [Member]
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 [Member]
Ordinary income (in hundredths)	100.00%
Return of Capital (in hundredths)	0.00%
Capital Gain Distribution (in hundredths)	0.00%
Class A Common Shares [Member]
Ordinary income (in hundredths)	100.00%	79.49%	76.34%
Return of Capital (in hundredths)	0.00%	20.51%	23.66%
Capital Gain Distribution (in hundredths)	0.00%	0.00%	0.00%