Shareholders' Equity (Schedule of Dividends) (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Class Of Stock [Line Items]
Common stock	$ 0.010	$ 0.050	$ 0.070	$ 0.150
Series B Preferred Stock [Member]
Class Of Stock [Line Items]
Cumulative Redeemable Preferred Stock	$ 0.453	$ 0.453	$ 1.359	$ 1.359
Dividend rate percentage	7.25%	7.25%	7.25%	7.25%
Series C Preferred Stock [Member]
Class Of Stock [Line Items]
Cumulative Redeemable Preferred Stock	$ 0.406	$ 0.406	$ 1.219	$ 1.219
Dividend rate percentage	6.50%	6.50%	6.50%	6.50%