Earnings Per Share (Narrative) (Details) - $ / shares shares in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Series C Preferred Shares [Member]
Anitidlutive securities exluded from computation of earnings per share [Line Items]
Common shares upon conversion of convertible preferred shares	2,200	2,100
Preferred Stock, Dividend Rate, Percentage	5.75%
Series E Preferred Shares [Member]
Anitidlutive securities exluded from computation of earnings per share [Line Items]
Common shares upon conversion of convertible preferred shares	1,700	1,600
Preferred Stock, Dividend Rate, Percentage	9.00%
Share Options [Member]
Anitidlutive securities exluded from computation of earnings per share [Line Items]
Common shares upon conversion of convertible preferred shares	62	4
Performance Shares [Member]
Anitidlutive securities exluded from computation of earnings per share [Line Items]
Common shares upon conversion of convertible preferred shares	62
Minimum [Member]
Anitidlutive securities exluded from computation of earnings per share [Line Items]
Share-based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit	$ 56.94	$ 73.84
Maximum [Member]
Anitidlutive securities exluded from computation of earnings per share [Line Items]
Share-based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit	$ 76.63	$ 76.63

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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