Earnings Per Share (Narrative) (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Anitidlutive securities exluded from computation of earnings per share [Line Items]
Exercise price range, lower limit	$ 73.84	$ 61.79	$ 61.79
Exercise price range, upper limit	$ 76.63	$ 76.63	$ 76.63
Series C Preferred Shares [Member]
Anitidlutive securities exluded from computation of earnings per share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2,200	2,100	2,100
Preferred share dividend percentage	5.75%
Series E Preferred Shares [Member]
Anitidlutive securities exluded from computation of earnings per share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,600	1,600	1,600
Preferred share dividend percentage	9.00%
Stock Options [Member]
Anitidlutive securities exluded from computation of earnings per share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	4	26	7