Shareholders' Equity (Schedule of Dividends) (Details) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Class Of Stock [Line Items]
Common stock	$ 0.050	$ 0.050
Series B [Member]
Class Of Stock [Line Items]
Cumulative Redeemable Preferred Stock	$ 0.453	$ 0.453
Dividend rate percentage	7.25%	7.25%
Series C Preferred Stock [Member]
Class Of Stock [Line Items]
Cumulative Redeemable Preferred Stock	$ 0.406	$ 0.406
Dividend rate percentage	6.50%	6.50%