Earnings Per Share (Anti-Dilutive Securities Of Common Shares) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total anti-dilutive securities (in shares)	0	2	1,935
Share Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total anti-dilutive securities (in shares)	0	2	463
Operating Partnership Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total anti-dilutive securities (in shares)	0	0	1,472