Earnings Per Share (Components Of Earnings Per Common Share - Basic And Diluted) (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Continuing Operations:
Income from continuing operations	$ 35,894	$ 39,229	$ 93,496	$ 139,357
Gain on Sale of Property	38,579	22,108	86,566	68,298
Net income attributable to noncontrolling interests	(1,844)	(9,436)	(12,755)	(12,864)
Net income attributable to common shareholders - basic	72,629	51,901	167,307	194,791
Income attributable to operating partnership units	515	499	1,567	1,497
Net income attributable to common shareholders - diluted	$ 73,144	$ 52,400	$ 168,874	$ 196,288
Denominator:
Weighted average shares outstanding – basic (in shares)	127,801	127,304	127,734	125,569
Effect of dilutive securities:
Share options and awards (in shares)	844	1,022	877	1,100
Operating partnership units (in shares)	1,432	1,462	1,450	1,462
Weighted average shares outstanding – diluted (in shares)	130,077	129,788	130,061	128,131