Earnings Per Share (Schedule Of Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
INCOME FROM CONTINUING OPERATIONS	$ 58,107	$ 56,253	$ 175,136	$ 166,701
Less: Preferred share dividends	(177)	(136)	(448)	(406)
Less: Income from continuing operations attributable to noncontrolling interests	(2,105)	(1,982)	(5,537)	(5,961)
Less: Earnings allocated to unvested shares	(317)	(170)	(785)	(534)
Income from continuing operations available for common shareholders	55,508	53,965	168,366	159,800
Gain on sale of real estate and change in control of interests, net	50,775	4,706	69,659	31,133
Net income available for common shareholders, basic and diluted	$ 106,283	$ 58,671	$ 238,025	$ 190,933
Weighted average common shares outstanding—basic	72,091	71,319	71,983	70,626
Stock options	115	170	127	178
Weighted average common shares outstanding—diluted	72,206	71,489	72,110	70,804
Earnings Per Common Share, Basic	$ 1.47	$ 0.82	$ 3.31	$ 2.70
Earnings per common share, diluted	$ 1.47	$ 0.82	$ 3.30	$ 2.70
Income from continuing operations attributable to the Trust	$ 56,002	$ 54,271	$ 169,599	$ 160,740