Earnings Per Share (Components Of Earnings Per Common Share - Basic And Diluted) (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net Income	$ 118,959	$ 322,575	$ 345,343
Net income attributable to noncontrolling interests	6,810	7,140	17,742
Net income attributable to common shareholders - basic	112,149	315,435	327,601
Income attributable to operating partnership units	0	2,112	0
Net income attributable to common shareholders - diluted	$ 112,149	$ 317,547	$ 327,601
Denominator:
Weighted average shares outstanding - basic (in shares)	127,291	127,842	127,651
Effect of dilutive securities:
Share options and awards (in shares)	878	842	790
Operating partnership units (in shares)	0	1,432	0
Weighted average shares outstanding - diluted (in shares)	128,169	130,116	128,441